Pre-exposure rabies prophylaxis: a systematic review

Bull World Health Organ 2017;95:210–219C | doi: http://dx.doi.org/10.2471/BLT.16.173039 Systematic reviews 210 Pre-exposure rabies prophylaxis: a systematic review Jocelyn A Kessels,a Sergio Recuenco,b Ana Maria Navarro-Vela,c Raffy Deray,d Marco Vigilato,e Hildegund Ertl,f David Durrheim,g Helen Rees,h Louis H Nel,i Bernadette Abela-Ridderj & Deborah Briggsk Introduction Rabies is a preventable yet fatal disease that is responsible for approximately 59 000 deaths each year.1 However, widespread underreporting of rabies cases means that the actual number of deaths is likely to be higher. Poor and rural populations are disproportionately affected, with the majority of deaths occurring in children younger than 15 years in Asia and Af- rica.2 Ninety-nine per cent of human rabies cases result from dog bites and, once symptoms begin, the disease is almost invariably fatal.3 Human rabies is preventable through canine vaccination to eliminate rabies at its source or by adminis- tering rabies vaccines and immunoglobulin following bites, scratches or saliva exposure from suspected rabid mammals (i.e. postexposure prophylaxis).4 Another preventive strategy is pre-exposure prophylaxis, which involves giving a series of intramuscular or intradermal injections of rabies vaccine to prime the immune system. This enables fast recall of memory immune responses once a person is re-exposed to the virus.4 Moreover, people who have received pre-exposure prophylaxis require fewer doses of postexposure rabies vaccine and can be treated without rabies immunoglobulin, which is costly and difficult to procure.4 Al- though preventing rabies in dogs is the most cost-effective way of preventing human rabies deaths, pre-exposure prophylaxis is valuable for people at a high disease risk,5 particularly in areas where controlling disease in the animal reservoir is dif- ficult or has not been implemented and in areas where access to postexposure prophylaxis and rabies immunoglobulin is unreliable or nonexistent. National pre-exposure prophylaxis programmes for high-risk populations have been implemented in Peru and the Philippines.6,7 In 2010, a World Health Organization (WHO) position paper on rabies vaccines called for studies on the feasibility, cost–effectiveness and long-term impact of incorporating vaccines derived from cell culture or embryonated eggs into immunization programmes for children where canine rabies is a public health problem.5 The paper also made recommen- dations on pre-exposure prophylaxis regimens and on the frequency of booster vaccinations and serological surveillance for at-risk individuals, such as veterinarians. The aim of this study was to review the scientific literature published between 2007 and 2016, as well as field data, to assess the current use and cost–effectiveness of pre-exposure rabies prophylaxis (excluding travel vaccines), particularly in children and in high-risk settings, in the context of recommendations made in the 2010 WHO rabies vaccine position paper on pre-exposure prophylaxis and booster vaccine administration. Objective To review the safety and immunogenicity of pre-exposure rabies prophylaxis (including accelerated schedules, co-administration with other vaccines and booster doses), its cost–effectiveness and recommendations for use, particularly in high-risk settings. Methods We searched the PubMed, Centre for Agriculture and Biosciences International, Cochrane Library and Web of Science databases for papers on pre-exposure rabies prophylaxis published between 2007 and 29 January 2016. We reviewed field data from pre-exposure prophylaxis campaigns in Peru and the Philippines. Findings Pre-exposure rabies prophylaxis was safe and immunogenic in children and adults, also when co-administered with routine childhood vaccinations and the Japanese encephalitis vaccine. The evidence available indicates that shorter regimens and regimens involving fewer doses are safe and immunogenic and that booster intervals could be extended up to 10 years. The few studies on cost suggest that, at current vaccine and delivery costs, pre-exposure prophylaxis campaigns would not be cost-effective in most situations. Although pre- exposure prophylaxis has been advocated for high-risk populations, only Peru and the Philippines have implemented appropriate national programmes. In the future, accelerated regimens and novel vaccines could simplify delivery and increase affordability. Conclusion Pre-exposure rabies prophylaxis is safe and immunogenic and should be considered: (i) where access to postexposure prophylaxis is limited or delayed; (ii) where the risk of exposure is high and may go unrecognized; and (iii) where controlling rabies in the animal reservoir is difficult. Pre-exposure prophylaxis should not distract from canine vaccination efforts, provision of postexposure prophylaxis or education to increase rabies awareness in local communities. a School of Veterinary Science, University of Queensland Gatton Campus, Via Warrego Highway, Gatton, Queensland 4343, Australia. b National Centre for Public Health, Instituto Nacional de Salud, Lima, Peru. c Directorate General of Strategic Interventions in Public Health, Ministry of Health, Lima, Peru. d Diseases Prevention and Control Bureau, Department of Health, Manilla, Philippines. e Veterinary Public Health Unit, Pan American Health Organisation–World Health Organisation, Rio de Janeiro, Brazil. f Wistar Institute Vaccine Center, Philadelphia, United States of America (USA). g Hunter Medical Research Institution, University of Newcastle, Newcastle, Australia. h Wits Reproductive Health and HIV Institute, University of Witwatersrand, Johannesburg, South Africa. i Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria, South Africa. j Neglected Zoonotic Diseases, World Health Organization, Geneva, Switzerland. k College of Veterinary Medicine, Kansas State University, Manhattan, USA. Correspondence to Jocelyn A Kessels (email: jocelyn.kessels@uq.net.au). (Submitted: 7 March 2016 – Revised version received: 15 September 2016 – Accepted: 28 September 2016 – Published online: 25 November 2016 ) S stematic reviews Bull World Health Organ 2017;95:210–219C| doi: http://dx.doi.org/10.2471/BLT.16.173039 211 Systematic reviews Pre-exposure rabies prophylaxisJocelyn A Kessels et al. Methods Literature search Our literature review was intended as an update of the review of the evidence on pre-exposure prophylaxis carried out for the 2010 WHO rabies vaccine position paper. Our search was conducted ac- cording to preferred reporting items for systematic reviews and meta-analyses guidelines.8 We searched the PubMed, Centre for Agriculture and Biosciences International, Cochrane Library and Web of Science databases for papers on pre-exposure rabies prophylaxis published between 2007 and 29 January 2016 (Fig. 1) using the search string: “ra- bies” AND “pre-exposure” AND (“pro- phylaxis” OR “vaccin*”). We started at 2007 to include studies published after completion of the review for the WHO position paper. Additional references were obtained from citations in relevant publications. We excluded studies that assessed: (i) postexposure prophylaxis only; or (ii) pre-exposure prophylaxis either occupationally or in travellers. As we considered the safety and im- munogenicity of WHO-recommended vaccination regimens for pre-exposure prophylaxis to be well established, we also excluded papers that confirmed the efficacy of these regimens, unless they specifically assessed the safety and immunogenicity of pre-exposure prophylaxis in children or given in combination with other vaccines. We included any type of study, in any language and from any country that as- sessed: (i) pre-exposure prophylaxis in children; (ii) the cost–effectiveness of pre-exposure prophylaxis; (iii) acceler- ated or revised pre-exposure prophylaxis regimens; or (iv) booster vaccination recommendations. Studies that assessed the cost of pre-exposure prophylaxis and its use in children were included regard- less of publication date. Field data We reviewed field data from completed and ongoing pre-exposure prophylaxis campaigns in Peru and the Philippines. In Peru, the campaigns targeted people living in remote areas who were at risk of contracting rabies from vampire bats, whereas in the Philippines they targeted children at risk of dog-transmitted rabies. Peru In Peru, vampire bats are a common source of rabies: the life-time risk of a bat bite in rural Amazon basin popula- tions is reported to be 41 to 88%.9,10 Outbreak reports and responses are delayed by the remoteness of these populations and controlling rabies in the bat reservoir is challenging.11 Following a rabies outbreak in 2011, Peru began a mass pre-exposure prophylaxis vac- cination campaign that targeted people in Condorcanqui and Bagua Provinces at a high risk of rabies from vampire bats.6 The risk was regarded as high in these provinces because: (i) bat bites were common; (ii) there was evidence of rabies in circulation; (iii) housing condi- tions increased vulnerability; (iv) pro- tective measures among the population were lacking; (v) tools for vector control were lacking; and (vi) the remote loca- tion of villages delayed health service responses. The campaign involved ad- ministering three intramuscular doses of human diploid cell or purified Vero cell vaccine on days 0, 7 and 28. Villages were prioritized to receive the interven- tion by classifying their epidemiological risk using the following variables: (i) the endemicity of bat rabies; (ii) the num- ber of human rabies cases within the previous 6 months; (iii) the number of livestock rabies cases within the previ- ous 6 months; (iv) the frequency of vampire bat bites (where there was bite surveillance); (v) history of postexpo- sure prophylaxis; and (vi) important, recent ecological changes, such as an increase in the population, a change in the feeding habits of vampire bats, illegal mining or deforestation. Among villages with a history of postexposure prophylaxis interventions, priority was given to those in which the intervention took place more than 1 year previously, those where a low percentage of the population had received postexposure prophylaxis and those close to the site of a recent outbreak or of documented circulation of the rabies virus. Philippines In the Philippines, pre-exposure rabies prophylaxis is recommended as an additional intervention for high-risk Fig. 1. Flowchart showing the selection of publications on pre-exposure rabies prophylaxis, 2007–2016 333 publications identified through database search PubMed (n = 109) Centre for Agriculture and Biosciences International (n = 85) Cochrane Library (n = 13) Web of Science (n = 126) 11 publications identified from bibliographies 31 publications underwent full text review 344 publications identified in total 174 duplicate publications excluded 139 publications excluded 30 assessed PREP in travellers 8 assessed PREP occupational use 75 did not specifically assess PREP 9 assessed WHO recommended regimens 15 assessed commercial products 2 had an inaccessible full text 170 publications underwent title and abstract review 11 on PREP in children 4 on PREP in high-risk settings 3 on PREP cost–effectiveness 9 on accelerated or revised PREP regimens 4 on booster vaccination recommendations PREP: pre-exposure prophylaxis; WHO: World Health Organization. 212 Systematic reviews Pre-exposure rabies prophylaxis Jocelyn A Kessels et al. Bull World Health Organ 2017;95:210–219C | doi: http://dx.doi.org/10.2471/BLT.16.173039 individuals, such as children and people at occupational exposure. In 2007, the Philippine Government implemented a Department of Health recommen- dation that free routine pre-exposure prophylaxis should be provided for school children aged 5 to 14 years who are living in high-risk areas.7,12 To be included an area had to have: (i) an incidence of human and canine rabies above the national average; (ii) an inci- dence of animal bites above the national average; (iii) no or low canine vaccina- tion coverage, which was defined as less than 30% coverage of the estimated dog population; and (iv) limited access to postexposure prophylaxis, for example, due to geographical isolation, inad- equate treatment facilities or poverty. Schoolchildren were targeted because almost 50% of all rabies exposure in the Philippines occurs in children younger than 15 years. Child deaths due to rabies are associated with poverty and, where postexposure prophylaxis is available, with limited or delayed access to health services. The rationale for pre-exposure prophylaxis was that it: (i) may protect children who do not receive postex- posure prophylaxis, for example, after unremarked exposure (i.e. if their anti- body titre at exposure is ≥ 0.5 IU/mL); (ii) may protect patients when postexpo- sure prophylaxis is delayed; (iii) acceler- ates antibody responses to postexposure prophylaxis; and (iv) reduces the cost of postexposure prophylaxis by removing the need for rabies immunoglobulin and reducing the number of postexposure prophylaxis doses required from 8 to 2 (Table 1). The pre-exposure prophylaxis schedule consisted of administering three intradermal doses of purified Vero cell or chick embryo cell vaccine on days 0, 7 and 28. Results The systematic review of the literature identified 31 publications on pre- exposure rabies prophylaxis that met inclusion criteria (Table 2). Safety and immunogenicity in children Literature search The search identified 11 studies on the safety and immunogenicity of pre- exposure prophylaxis in children aged 2 months to 15 years, including two published before 2007 (Table 3). All found it safe and immunogenic in both infants and children. Three found it safe and immunogenic for up to 5 years when given in combination with other childhood vaccines such as those against Japanese encephalitis, diphtheria, teta- nus, pertussis and poliomyelitis (both oral and inactivated vaccines).27,34,40 High-risk settings Literature search Pre-exposure prophylaxis programmes for high-risk populations, and especially children, were strongly recommended in reports of expert meetings on rabies and child health in Asia and the Middle East.6,13,19 In India, the Academy of Pe- diatrics called for its inclusion in the immunization schedule for high-risk children younger than 18 years.39 Peru In 2011, pre-exposure prophylaxis was administered in 286 localities in the Amazonas Region: 86% were in Condor- canqui Province and 14% were in Bagua Province. In total, 13 986 people were immunized. In these areas, the number of rabies deaths dropped from 13 in 2010 and 20 in 2011 to zero child deaths and only two adult deaths (both had refused vaccination) in 2012.6 Fig. 2 shows the number of human rabies deaths in Bagua and Condorcanqui Provinces between 1975 and 2015. The number of reported bat bites, which is used as a surrogate for rabies exposure, decreased between 2010 and 2013 (Table 4) but there was no change in the risk factors for bites, such as the number of houses bats could enter. In areas adjacent to the Amazonas Region, in which pre-exposure prophy- laxis was not implemented, there were outbreaks of human rabies in 2011, 2013 and 2015 (unpublished data, 2015). The programme was extended until 2015 to cover an additional 423 communities in Bagua and Condorcanqui Provinces at a high risk of rabies. By 2015, 71 400 people in the Amazonas Region (i.e. 86% of the population) had received pre-exposure prophylaxis and, by the end of 2014, 121 285 people (i.e. 76% of the target population) in Cusco, Junín and Loreto Regions had also received it. No serious adverse events were reported. Philippines By April 2010, the routine pre-exposure prophylaxis immunization programme had achieved an average coverage of 47.25% in the target population: 21 637 high-risk children in 31 schools in seven regions were immunized (unpublished data, 2010). In the town of Cabusao, 188 schoolchildren received at least one vac- cine dose (i.e. 86% of those eligible) and 90% of the 188 completed the pre-exposure prophylaxis regimen. Subsequently, 3.5% received postexposure prophylaxis within 3 years following suspected exposure. The programme was stopped in 2011 because a large increase in rabies exposure led to a vaccine shortage and priority was given to the immunization of people involved in canine vaccination campaigns. Pre- exposure prophylaxis of schoolchildren was planned to restart in 2016. Cost–effectiveness Literature search Few recent studies have assessed the cost–effectiveness of pre-exposure ra- bies prophylaxis. One study estimated Table 1. Postexposure rabies prophylaxis regimens, by pre-exposure prophylaxis, the Philippines, 2007 Exposure categorya Following pre-exposure rabies prophylaxis Without pre-exposure rabies prophylaxis Rabies vaccine Equine rabies immunoglobulin Rabies vaccine Equine rabies immunoglobulin Category II 1 intradermal dose on days 0 and 3 (i.e. 2 doses) No 2 intradermal doses on days 0, 3, 7 and 28 (i.e. 8 doses) No Category III 1 intradermal dose on days 0 and 3 (i.e. 2 doses) No 2 intradermal doses on days 0, 3, 7 and 28 (i.e. 8 doses) Yes, with the volume dependent on body weight a Category-II exposure is defined as nibbling of uncovered skin, minor scratches or abrasions without bleeding and category-III exposure, as single or multiple transdermal bites or scratches, contamination of mucous membranes with saliva from licks, licks on broken skin, exposures to bats.5 213 Systematic reviews Pre-exposure rabies prophylaxisJocelyn A Kessels et al. Bull World Health Organ 2017;95:210–219C| doi: http://dx.doi.org/10.2471/BLT.16.173039 the annual global direct cost of admin- istering postexposure rabies prophylaxis at 1.7 billion United States dollars (US$), plus an additional US$ 1.3 billion in lost income.1 In a cost assessment of pre-exposure prophylaxis, researchers showed that it would be cost-neutral if 1% of children were exposed to rabies each year and if the price of the vaccine did not exceed US$ 1.32 per dose, once the cost of postexposure prophylaxis boosters required after exposure was taken into account.30 The acceptable vaccine cost increased in proportion to the incidence of rabies. In a Thai study, the estimated cost of pre-exposure prophylaxis for children ranged from US$ 2.00 to 7.25 per child depending on the schedule and vaccine used: there was an additional cost of US$ 18.00 to 23.50 per child if postexposure prophylaxis was required later.17 Pre-exposure pro- phylaxis became cost-comparable to the least expensive postexposure schedule (i.e. intradermal immunization without rabies immunoglobulin) when the an- nual risk of a dog bite was approximately 23%. If equine or human rabies immu- noglobulin was used with postexposure vaccines, pre-exposure prophylaxis was cost-comparable when the annual risk of a dog bite was 7% or 3%, respectively. As over 30% of Thai children had been bitten by a dog by the age of 15 years, it was estimated that the actual incidence of dog bites in the population of central Table 2. Publications on pre-exposure rabies prophylaxis, systematic review of the literature, 2007–2016 Reference Publication type Publication date Study location Prophylaxis Vaccinees Aikimbayev et al.13 Meeting report 2014 Middle East, Eastern Europe, Central Asia N/A Children and adults Banga et al.14 Journal article 2014 United States N/A Adults Brown et al.15 Journal article 2011 United Kingdom N/A Adults Brown et al.16 Journal article 2008 United Kingdom N/A Adults Chulasugandha et al.17 Journal article 2006 Thailand PVRV, PCECV Children Cunha et al.18 Journal article 2010 Brazil PVRV, PCECV Adults Dodet et al.19 Meeting report 2009 Viet Nam N/A Children and adults Dodet7 Meeting report 2010 Philippines N/A Children and adults Hampson et al.1 Journal article 2015 Worldwide N/A Children and adults Jelinek et al.20 Journal article 2015 Germany PCECV, Japanese encephalitis vaccine Adults Kamoltham et al.21 Journal article 2011 Thailand PVRV Children Kamoltham et al.22 Journal article 2007 Thailand PCECV Children Khawplod et al.23 Journal article 2008 Thailand PCECV, PVRV Adults Khawplod et al.24 Journal article 2012 Thailand PCECV, PVRV Adults Khawplod et al.25 Journal article 2007 Thailand PCECV, PVRV Adults Lang et al.26 Journal article 1997 Viet Nam PVRV Children Lang et al.27 Journal article 2009 Viet Nam PVRV combined with vaccination against diphtheria, tetanus, pertussis (whole-cell vaccine) and poliomyelitis (inactivated vaccine) Children Lau & Hohl28 Journal article 2013 Australia PCECV Children and adults Lim & Barkham29 Journal article 2010 Singapore PVRV Adults Liu30 Journal article 2012 Worldwide N/A Children Lumbiganon et al.31 Journal article 1989 Thailand PCECV Children Malerczyk et al.32 Journal article 2013 Germany PCECV Children Mills et al.33 Journal article 2011 Australia HDCV Children and adults Pengsaa et al.34 Journal article 2009 Thailand PCECV combined with Japanese encephalitis vaccine Children Ravish et al.35 Journal article 2013 India PCECV Children Shanbag et al.36 Journal article 2008 India PVRV, PCECV Children Strady et al.37 Journal article 2009 France HDCV, PVRV Children Sudarshan et al.38 Journal article 2011 Worldwide N/A Children and adults Vashishtha et al.39 Journal article 2014 India N/A Children Vien et al.40 Journal article 2008 Viet Nam PVRV combined with vaccination against diphtheria, tetanus, pertussis (whole-cell vaccine) and poliomyelitis (inactivated vaccine) Children Wongsaroj et al.41 Journal article 2013 Thailand PVRV Adults HDCV: human diploid cell vaccine; N/A: not available; PCECV: purified chick embryo cell vaccine; PVRV: purified Vero cell rabies vaccine. 214 Systematic reviews Pre-exposure rabies prophylaxis Jocelyn A Kessels et al. Bull World Health Organ 2017;95:210–219C | doi: http://dx.doi.org/10.2471/BLT.16.173039 Thailand was only 2.3% per year. Conse- quently, pre-exposure prophylaxis with currently licensed vaccines would not be cost-effective in this setting. Peru The cost of the mass pre-exposure pro- phylaxis campaign was estimated to be US$ 4 111 000, of which US$ 3 560 000 was the cost of the vaccine. The average cost per immunized person was US$ 69. By assuming that the risk of rabies was constant (i.e. the rabies virus remained in circulation and the risk of a bat bite was unchanged) and that, each year, ra- bies caused 20 deaths per 50 000 people in Condorcanqui Province without pre- exposure prophylaxis, we estimated the cost of pre-exposure prophylaxis to be US$ 205 000 per life saved after the first year.6 After 5 years, the cost decreased to US$ 41 000 per life saved. This amount is comparable to the cost of treating one rabies-infected individual, includ- ing the cost of transport, laboratory diagnosis and hospitalization. The use of intradermal vaccinations would reduce the vaccination cost by 80%. However, intramuscular vaccination continues to be used in Peru because: (i) there is no shortage of rabies vaccine in the coun- try; (ii) staff have not been trained in the multiple uses of rabies vaccine vials for intradermal administration; and (iii) the national authorities elected to use the intramuscular route to minimize the risk of errors in vaccine administration. Philippines Pre-exposure prophylaxis with three doses of purified Vero cell or chick em- bryo cell vaccine was estimated to cost US$ 4.77 per patient (unpublished data, 2015; (Table 5). For a patient weighing between 26 and 50 kg, pre-exposure prophylaxis reduced the cost of postex- posure prophylaxis by up to 38% follow- ing category-II exposure (i.e. “nibbling of uncovered skin, minor scratches or abrasions without bleeding”)5 and by up to 85% following category-III exposure (i.e. “single or multiple transdermal bites or scratches, contamination of mucous membranes with saliva from licks, licks on broken skin, exposures to bats”),5 af- ter the cost of pre-exposure prophylaxis was taken into account. Accelerated or revised regimens Nine studies investigated the safety and immunogenicity of an accelerated or re- vised pre-exposure prophylaxis regimen (Table 6; available at http://www.who. Table 3. Pre-exposure rabies prophylaxis in children, systematic review of the literature, 1989–2016 Reference Age group (years) Vaccine Vaccination route Regimen Antibody titre (IU/mL)a Comments Primary response Recall response Lang et al.,27 Vien et al.40 and Lang et al.26b < 1 PVRV Intramuscular 2 doses at 2 and 4 months of age 20.1 > 1 (assessed after 5 years) Combined with vaccination against diphtheria, tetanus, pertussis and polio (inactivated vaccine)27,40 Pengsaa et al.34 1–1.5 PCECV Intramuscular or intradermal 1 dose on days 0, 7 and 28; or 1 dose on days 0 and 28 15–41 (intramuscular); 4.1–8.5 (intradermal) 103–299 (intramuscular); 8.0–38 (intradermal) – both assessed after 1 year Combined with vaccination against Japanese encephalitis: antibody titres were higher following intramuscular than intradermal administration Lumbiganon et al.31,b 2–15 PCECV Intramuscular or intradermal 1 dose on days 0, 7 and 28 4.7–47 ND Antibody titres were higher following intramuscular than intradermal administration Kamoltham et al.21 and Kamoltham et al.22 5–8 PCECV Intradermal 1 dose on days 0, 7 and 28; or 1 dose on days 0 and 28 > 2 8.9–27.3 (assessed after ≥ 1 year) All children had an antibody titre > 0.5 IU/mL within 14 days of the booster dose, regardless of the time interval and the number of doses initially received Ravish et al.35 5–10 PCECV Intradermal 1 dose on days 0, 7 and 21 ND ND 80.4% of children completed treatment; there were no serious adverse reactions Shanbag et al.36 6–13 PVRV or PCECV Intramuscular 1 dose on days 0, 7 and 28 12.2–14.5 ND None Strady et al.37 12–79 HDCV or PVRV Intramuscular 1 dose on days 0, 7 and 28; or 1 dose on days 0 and 28 0.1–48 (assessed after 1 year) 51 (3 doses); 13 (2 doses) – both assessed after 1 year None Malerczyk et al.32 < 15 PCECV N/A N/A N/A N/A This review of > 1200 children treated over > 25 years concluded that the vaccine was safe and immunogenic, whether given intramuscularly or intradermally HDCV: human diploid cell vaccine; N/A: not applicable; ND: not determined; PCECV: purified chick embryo cell vaccine; PVRV: purified Vero cell rabies vaccine. a The values are either geometric means or ranges, as appropriate. b Although this study was published before 2007, it has been included because the results are still relevant. 215 Systematic reviews Pre-exposure rabies prophylaxisJocelyn A Kessels et al. Bull World Health Organ 2017;95:210–219C| doi: http://dx.doi.org/10.2471/BLT.16.173039 int/bulletin/volume/95/03/16-173039). Administering all vaccine doses within 1 week22,23,28,33 or in one23,24 or two visits41 elicited an adequate antibody titre of 0.5 IU/mL or higher for up to 1 year,23–25,28,33 even when given in combination with Japanese encephalitis vaccine.20 Adequate titres were observed in people who received a total dose of at least 2 IU of intradermal pre-exposure prophylaxis.15 Factors associated with an inadequate antibody titre included: (i) a period of more than 21 days between the first and third doses; (ii) male sex; (iii) vaccine type or manufacturer; and (iv) a body mass index of 25 kg/m2 or higher.14 Booster vaccinations Four studies investigated recommen- dations on booster vaccines (Table 7; available at http://www.who.int/bul- letin/volume/95/03/16-173039). They concluded that: (i) the interval between booster vaccinations could be extended by up to 10 years;16 (ii) serological surveillance or booster vaccination after 1 year is advisable for people in high-risk occupations;29 (iii) serological testing after the third intramuscular or intradermal pre-exposure prophylaxis dose is unnecessary;18 and (iv) healthy subjects may not require postexposure prophylaxis boosters on re-exposure to rabies for up to 3 months after pre- exposure or previous postexposure prophylaxis.38 Discussion Several studies demonstrated that pre- exposure rabies prophylaxis was safe and immunogenic in children and could be co-administered with other childhood vaccines.21,22,27,32,34–37,40 In addition, it could be given with the Japanese en- cephalitis vaccine in both adults and children. In most African countries pre-exposure rabies prophylaxis is un- likely to be included in the expanded programme on immunization because of competing priorities and because postexposure prophylaxis would still be required following suspected contact. Nevertheless, expert consultations ad- vocate vaccination for people in remote, high-risk areas6,19,36 and national pre- exposure prophylaxis programmes have been implemented in Peru and the Phil- ippines.6,7 In Peru, the programme was successful in preventing child deaths due to bat rabies in high-risk areas, which demonstrates the value of targeted pre- exposure prophylaxis in places where controlling disease in the animal res- ervoir is challenging.11 Although it can be difficult for individuals to recall the date of pre-exposure prophylaxis, this does not undermine its usefulness for saving human lives in situations where exposure is uncertain or there is lim- ited access to biologicals. Vaccination certificates are often treasured and kept safe and, in Peru, the identification and recording of vaccinated individuals has improved nationally. Pre-exposure rabies prophylaxis is also associated with cost savings because fewer postexposure vaccinations and no rabies immunoglobulin are required following suspected exposure. How- ever, the few studies that assessed costs suggest that community vaccination at current vaccine and delivery costs would not be cost-effective in most situ- ations.1,17,30,42,43 Preliminary studies on accelerated or revised regimens indicate that 1-week or even single-day regimens may be as effective as the recommended 3- to 4-week regimen: shorter treatment and fewer doses would make treatment simpler and less expensive. The development of a more im- munogenic rabies vaccine that provides life-long immunological memory with a single dose and that can be preserved at ambient temperatures, thereby elimi- nating the need for a cold chain, would make pre-exposure prophylaxis simpler and more cost-effective. The ideal vac- cine would induce an antibody titre that remained above 0.5 IU/mL for decades and would protect people who fail to receive prompt booster immunization following exposure. In animal studies, attempts have been made to increase the current vaccine’s immunogenicity using adjuvants,44,45 genetic manipula- Fig. 2. Human rabies deaths, Amazonas Region, Peru, 1975–2015 No . o f h um an ra bi es d ea th s 30 25 20 15 10 5 0 Year 1975 1980 1985 1990 1995 2000 2005 2010 2015 Start of national pre-exposure rabies prophylaxis programme for high-risk populations Notes: The Amazonas Region is the political division of Peru that includes Condorcanqui and Bagua Provinces, not the Amazon ecological region. All human rabies deaths reported in the figure occurred in Bagua and Condorcanqui Provinces. Table 4. Bat bites by region, Peru, 2009–20136 Region No. of bat bites reported % of all reported bat bites 2009 2010 2011 2012 2013 Total Amazonas 1 576 5 714 2 145 1 733 833 12 001 59.2 Cusco 50 169 36 441 20 716 3.5 Loreto 1 122 856 1 458 1 380 590 5 406 26.7 Junin 119 415 179 142 29 884 4.4 Others 465 224 295 229 41 1 254 6.2 All 3 332 7 378 4 113 3 925 1 513 20 261 100.0 216 Systematic reviews Pre-exposure rabies prophylaxis Jocelyn A Kessels et al. Bull World Health Organ 2017;95:210–219C | doi: http://dx.doi.org/10.2471/BLT.16.173039 tion,46 adenovirus vectors derived from chimpanzee viruses47 and attenuated measles viruses,48,49 which would enable combined early childhood immuniza- tion against both measles and rabies. Although pre-exposure prophylaxis using currently available biologicals may not be cost-effective in general, we be- lieve it could be beneficial in: (i) remote communities where access to postexpo- sure prophylaxis and rabies immuno- globulin is often delayed or nonexistent; (ii) situations in which the risk of expo- sure is high and may go unrecognized, for example, in young children or people exposed occupationally, such as veteri- narians; or (iii) places where controlling rabies in the animal reservoir is difficult and the risk of human exposure is high, such as in the Amazon basin where bat rabies is endemic. It is important that staff involved in canine rabies control receive pre-exposure prophylaxis be- cause of their higher risk of exposure. Currently, serological surveillance and booster vaccinations are recommended only for people at an occupational risk.5 Controlling canine rabies remains the cornerstone of preventing human rabies deaths. Pre-exposure prophylaxis should not distract from canine vaccination efforts, the provision of postexposure prophylaxis and education to raise local awareness of rabies. In high-risk areas, pre-exposure prophylaxis should be in- cluded in the expanded programme on immunization in children from 1 year of age,5 followed by a booster after 1 year. Vaccination should be documented with a certificate and any available medical re- cords should be updated. Targeted, mass campaigns in remote, high-incidence areas should be considered to provide protection for both children and adults and travel recommendations should be provided for newcomers. Accelerated vaccination regimes and novel vaccines that provide life-long immunity with a single dose and are stable at ambient temperatures would make pre-exposure prophylaxis more cost-effective and easier to implement. ■ Acknowledgements We thank staff at the National Zoonosis Strategy, Peruvian Ministry of Health, at the DIRESA Amazonas office and at the National Rabies Prevention and Control Program of the Philippine Department of Health. Competing interests: None declared. Table 5. Cost of postexposure rabies prophylaxis, the Philippines, 2007 Exposure categorya Cost in US$ per patient (treatment specifics) Savings per patient (weight range: 26–50 kg) who had pre-exposure prophylaxis Patients who had pre-exposure prophylaxis Patients (weight range: 26–50 kg) who did not have pre- exposure prophylaxis US$ (%) Category II 3.19 (2 intradermal doses of PCECV or PVRV at US$ 1.59 per dose; no RIG) 12.76 (8 intradermal doses of PCECV or PVRV at US$ 1.59 per dose; no RIG) 4.80 38 Category III 3.19 (2 intradermal doses of PCECV or PVRV at US$ 1.59 per dose; no RIG) 51.76 (8 intradermal doses PCECV or PVRV at US$ 1.59 per dose; 2 vials of ERIG at US$ 19.52 per vial) 43.80 85 ERIG: equine rabies immunoglobulin; PCECV: purified chick embryo cell vaccine; PVRV: purified Vero cell rabies vaccine; RIG: rabies immunoglobulin; US$: United States dollar. a Category-II exposure is defined as nibbling of uncovered skin, minor scratches or abrasions without bleeding and category-III exposure, as single or multiple transdermal bites or scratches, contamination of mucous membranes with saliva from licks, licks on broken skin, exposures to bats.5 Notes: The percentage saving is the cost saving divided by the cost of postexposure prophylaxis in a patient who did not have pre-exposure prophylaxis × 100. Prices were converted at a rate of US$ 1 per 47.65 Philippine pesos. The cost of postexposure rabies prophylaxis was the cost at bite centres taking part in a national pre-exposure rabies prophylaxis programme for high-risk populations, which was lower than in hospitals and private bite centres. The cost of pre-exposure rabies prophylaxis was US$ 4.77 per patient (US$ 1.59 per intradermal dose × 3). In calculating savings, the cost of pre-exposure prophylaxis was taken into account. صخلم ةيجهنم ةعجارم :راعُسلا ءادل ضرعتلا لىع ةقباسلا ةيبطلا ةياقولا تاءارجإب ةنيرقلا عانمتسلااو ناملأا لماوع ةعجارم ضرغلا )بلكلا ءاد( راعُسلا ضرلم ضرعتلا لىع ةقباسلا ةيبطلا ةياقولا نم اهيرغ عم ةيودلأا ميدقتو ،ةلّجعلما ةينمزلا لوادلجا لمشي ماب( تايصوتلاو ةفلكتلا ةيلاعفو ،)ةطشنلما تاعرلجاو تانيصحتلا .ةروطلخا ةيلاع تائيبلا في ًةصاخو ،لماعتسلااب ةصالخا زكرلماو ،PubMed تانايب دعاوق في ثحبلاب انمق ةقيرطلا ةكبشو Cochrane ةبتكمو ،ةيويلحا مولعلاو ةعارزلل ليودلا لىع ةقباسلا ةيبطلا ةياقولا تاءارجإب قلعتت تاسارد دايجلإ مولعلا ينب ام ةترفلا لىإ اهشرن خيرات دوعي يتلاو راعُسلا ضرلم ضرعتلا تانايبلا ةعجارمب انمقو .2016 رياني/نياثلا نوناك 29و 2007 ضرعتلا لىع ةقباسلا ةيبطلا ةياقولا تلاحم نم ةذوخألما ةيناديلما .ينبلفلاو ويرب في تتم يتلا راعُسلا ضرلم راعُسلا ضرلم ضرعتلا لىع ةقباسلا ةيبطلا ةياقولا تناك جئاتنلا دنعو ،رابكلاو لافطلأا ىدل عانمتسلااو ناملأا لماوع يعارت ةلوفطلا ةلحرم في ةمدقلما ةينيتورلا تانيصحتلا عم اهميدقت نأ لىإ ةرفوتلما ةلدلأا يرشتو .نيابايلا غامدلا باهتلا ينصتح عمو ميدقت لىع دمتعت يتلا ةيجلاعلا جمابرلاو صرقلأا ةيجلاعلا جمابرلا نكملما نم ناكو ،عانمتسلااو ناملأا لماوع يعارت لقأ تاعرج 10 لىإ لصي ام لىإ ةطشنلما تاعرلجا ينب ام ةينمزلا تاترفلا ةلاطإ تلاحم نأ لىإ ةفلكتلا لوح ةليلقلا تاساردلا يرشتو .تاونس ةفلكت تاذ نوكت نل ضرملل ضرعتلا لىع ةقباسلا ةيبطلا ةياقولا تانيصحتلل ةيلالحا تاقفنلا لىإ رظنلاب فقاولما بلغأ في ةلاعف ةقباسلا ةيبطلا ةياقولا ميدقت لىإ ةوعدلا نم مغرلا لىعو .اهميدقتو ةيلاع ةجردل ةضرعلما ةيناكسلا تاعاطقلل ضرملل ضرعتلا لىع جمابرلا قيبطت في ينبلفلاو ويرب لىع رملأا صرتقا دقف ،ةروطلخا نم 217 Systematic reviews Pre-exposure rabies prophylaxisJocelyn A Kessels et al. Bull World Health Organ 2017;95:210–219C| doi: http://dx.doi.org/10.2471/BLT.16.173039 ةلجعم ةيجلاع ةمظنأ ميدقت لبقتسلما في نكميو .ةمئلالما ةينطولا ىوتسم عفرو ةمدلخا ميدقت ةيلمع طيسبتل ةدجتسم تانيصتحو .ةفلكتلا في ةءافكلا لماوع راعُسلا ءادل ضرعتلا لىع ةقباسلا ةياقولا يعارت جاتنتسلاا لبس ترذعت ام اذإ )ا( :اهيلإ تافتللااب حصنُيو عانمتسلااو ناملأا ،ترخأت وأ ضرملل ضرعتلا دعب ةيجلاعلا ةياقولا لىع لوصلحا نم اهقح ىقلت لاو ةيلاع ضرعتلا رطامخ تناك ام اذإ )ب(و ئجلام في راعُسلا لىع ةرطيسلا تصعتسا ام اذإ )ـج(و ،مماتهلاا نأ ضرملل ضرعتلا لىع ةقباسلا ةياقولل يغبني لاو .تاناويلحا ضرعتلا لىع ةقحلالا ةياقولا وأ ،بلاكلا ينصتح دوهج نم صقتنت .ةيلحلما تاعمتجلما في راعُسلا ءادب يعولا ةدايزل ةيعوتلا وأ ،هل 摘要 狂犬病暴露前预防 ： 系统审查 目的 为了审查狂犬病暴露前预防（包括加速治疗，与 其他疫苗联合施药及加强剂量）的安全性与免疫原性， 以及其成本效益和可推荐使用性，尤其是在高发地区。 方 法 我 们 在 美 国 国 立 医 学 图 书 馆 (PubMed)、 国 际 农 业 和 生 物 研 究 中 心 (Centre for Agriculture and Biosciences International)、 考 科 蓝 图 书 馆 (Cochrane Library) 以及 Web of Science 数据库中查找了 2007 年 至 2016 年 1 月 29 日期间刊发的与狂犬病暴露前预防 相关的论文。此外，我们还回顾了秘鲁与菲律宾暴露 前预防运动的现场数据。 结果 狂犬病暴露前预防在儿童与成人人群中具有安全 性和免疫原性，此外在与其他儿童常规疫苗接种及流 行性乙型脑炎疫苗联合用药时也能发挥其安全性与免 疫原性。 现有证据表明短期及少剂量方案具有安全性 和免疫原性，其加强剂量间隔可延长至 10 年。 少数 成本研究表明，多数情况下，当前疫苗及其配送成本 以及暴露前预防活动的成本效益不高。 尽管早已提倡 针对高危人群采用暴露前预防，但仅有秘鲁与菲律宾 实施了适当的国家项目。 未来，快速治疗方案及新型 疫苗将有可能简化配送流程并提高可承受性。 结论 狂犬病暴露前预防具有安全性和免疫原性，应考 虑 ： (i) 暴露后预防受限或滞后的地方 ；(ii) 暴露风险 高且尚未发现的地方 ；以及 (iii) 控制狂犬病动物宿主 困难的地方。 暴露前预防不应转移犬只疫苗的接种工 作，此外还应提供接触后预防或教育以提高当地社区 的狂犬病意识。 Résumé Prophylaxie pré-exposition à la rage: un examen systématique Objectif Analyser l’innocuité et l’immunogénicité de la prophylaxie pré-exposition à la rage (notamment le schéma de vaccination accéléré, la co-administration d’autres vaccins et les injections de rappel), son rapport coût-efficacité ainsi que les recommandations d’utilisation, en particulier dans les zones à haut risque. Méthodes Nous avons recherché, dans les bases de données de PubMed, du Centre for Agriculture and Biosciences International, de la Cochrane Library et de Web of Science, des articles sur la prophylaxie pré-exposition à la rage publiés entre 2007 et le 29 janvier 2016. Nous avons aussi analysé des données de terrain provenant de campagnes pour la prophylaxie pré-exposition menées au Pérou et aux Philippines. Résultats La prophylaxie pré-exposition à la rage était sûre et immunogène pour les enfants et les adultes, même co-administrée avec les vaccins systématiques des enfants et le vaccin contre l’encéphalite japonaise. Les éléments disponibles indiquent que les programmes de vaccination plus courts ainsi que ceux comportant des doses plus faibles sont sûrs et immunogènes et que les intervalles de rappel pourraient aller jusqu’à 10 ans. Selon les rares études sur les coûts, en tenant compte du coût actuel des vaccins et de leur administration, dans la plupart des cas, les campagnes pour la prophylaxie pré-exposition ne seraient pas rentables. Même s’il a été recommandé d’appliquer une prophylaxie pré-exposition dans les populations à haut risque, seuls le Pérou et les Philippines ont mis en œuvre des programmes nationaux à cet égard. Dans l’avenir, des schémas de vaccination accélérés et de nouveaux vaccins pourraient en simplifier l’administration, à des prix plus abordables. Conclusion La prophylaxie pré-exposition à la rage est sûre et immunogène et devrait être envisagée: (i) lorsque l’accès à la prophylaxie post-exposition est limité ou tardif; (ii) lorsque le risque d’exposition est élevé et pourrait passer inaperçu; et (iii) lorsqu’il est difficile de lutter contre la rage dans le réservoir animal. La prophylaxie pré-exposition ne doit pas empêcher les efforts de vaccination des chiens, la prophylaxie post-exposition ou la sensibilisation à la prévention de la rage dans les communautés locales. Резюме Доконтактная профилактика бешенства: систематический обзор Цель Проанализировать безопасность и иммуногенность доконтактной профилактики бешенства (в том числе ускоренный курс вакцинации, назначение с другими вакцинами и ревакцинации), ее экономическую эффективность и рекомендации по применению, особенно в условиях высокого риска. Методы Авторы осуществили поиск статей по доконтактной профилактике бешенства, опубликованных между 2007 годом и 29 января 2016 года, в базах данных PubMed, Международного центра по сельскому хозяйству и биологическим наукам (CABI), Кокрановской библиотеки и Web of Science. Авторы проанализировали данные, полученные в рабочих условиях в ходе кампаний по доконтактной профилактике бешенства в Перу и на Филиппинах. Результаты Доконтактная профилактика бешенства была безопасной и способной вызывать иммунный ответ у детей и взрослых, в том числе в сочетании с плановой иммунизацией детей и вакцинацией против японского энцефалита. На основании доступных данных можно сделать вывод о том, что более короткие курсы и курсы с использованием меньшего 218 Systematic reviews Pre-exposure rabies prophylaxis Jocelyn A Kessels et al. Bull World Health Organ 2017;95:210–219C | doi: http://dx.doi.org/10.2471/BLT.16.173039 количества доз безопасны, вызывают иммунный ответ и интервалы ревакцинации могут быть увеличены до 10 лет. Судя по результатам немногочисленных анализов расходов, при текущих затратах на вакцинацию применение имеющейся в настоящее время вакцины в кампаниях по доконтактной профилактике не было бы экономически эффективно в большинстве случаев. Хотя доконтактная профилактика рекомендуется для групп населения, подвергающихся высокому риску, соответствующие национальные программы были внедрены только в Перу и на Филиппинах. В будущем ускоренные курсы лечения и новые вакцины, возможно, позволят упростить выполнение вакцинации и повысить ее ценовую доступность. Вывод Доконтактная профилактика бешенства безопасна, способна вызвать иммунный ответ и должна быть рекомендована: 1) когда доступ к постконтактной профилактике ограничен или предоставляется несвоевременно; 2) когда риск заражения велик или может быть не распознан; 3) когда борьба с бешенством у животных-носителей затруднительна. Доконтактная профилактика бешенства не должна быть поводом для отказа от мероприятий по вакцинации собак, проведения постконтактной профилактики или информационно-просветительской работы для привлечения внимания местного населения к проблеме бешенства. Resumen Profilaxis pre exposición a la rabia: una revisión sistemática Objetivo Analizar la seguridad y la inmunogenicidad de la profilaxis pre exposición a la rabia (incluidos programas acelerados, administración conjunta con otras vacunas y dosis de refuerzo), su rentabilidad y las recomendaciones de uso, especialmente en entornos de alto riesgo. Métodos Se realizaron búsquedas en PubMed, el Centro Internacional de Agricultura y Ciencias Biológicas, la Biblioteca Cochrane y la base de datos de la Web of Science en busca de documentos sobre la profilaxis pre exposición a la rabia publicados entre 2007 y el 29 de enero de 2016. Se analizaron datos archivados de campañas de profilaxis pre exposición en Filipinas y Perú. Resultados La profilaxis pre exposición a la rabia era segura e inmunogénica en niños y adultos, también cuando se administraba en conjunto con vacunas infantiles rutinarias y la vacuna de la encefalitis japonesa. Las pruebas disponibles indican que los regímenes más cortos y los que implican un menor número de dosis son seguros e inmunogénicos, y que los intervalos de refuerzo podrían ampliarse hasta 10 años. Los pocos estudios sobre el coste sugieren que, con los costes actuales de vacunación y suministro, las campañas de profilaxis pre exposición no serían rentables en la mayoría de las situaciones. A pesar de que la profilaxis pre exposición está destinada para poblaciones de alto riesgo, únicamente Filipinas y Perú han implementado los programas nacionales adecuados. En el futuro, los regímenes acelerados y las nuevas vacunas podrían simplificar el suministro y aumentar la asequibilidad. 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Emerg Infect Dis. 2006 Oct;12(10):1596–9. doi: http://dx.doi.org/10.3201/eid1210.060078 PMID: 17176582 48. Ramsauer K, Schwameis M, Firbas C, Müllner M, Putnak RJ, Thomas SJ, et al. Immunogenicity, safety, and tolerability of a recombinant measles- virus-based chikungunya vaccine: a randomised, double-blind, placebo- controlled, active-comparator, first-in-man trial. Lancet Infect Dis. 2015 May;15(5):519–27. doi: http://dx.doi.org/10.1016/S1473-3099(15)70043-5 PMID: 25739878 49. Rennick LJ, de Vries RD, Carsillo TJ, Lemon K, van Amerongen G, Ludlow M, et al. Live-attenuated measles virus vaccine targets dendritic cells and macrophages in muscle of nonhuman primates. J Virol. 2015 Feb;89(4):2192–200. doi: http://dx.doi.org/10.1128/JVI.02924-14 PMID: 25473055 219A Systematic reviews Pre-exposure rabies prophylaxisJocelyn A Kessels et al. Bull World Health Organ 2017;95:210–219C| doi: http://dx.doi.org/10.2471/BLT.16.173039 Ta bl e 6. Ac ce le ra te d or re vi se d pr e- ex po su re ra bi es p ro ph yl ax is, sy st em at ic re vi ew o f t he li te ra tu re , 2 00 7– 20 16 Re fe re nc e St ud y t yp e No . o f s tu dy pa rt ici pa nt s Va cc in e Va cc in at io n ro ut e Re gi m en An tib od y t itr e (IU /m L) Co m m en ts Pr im ar y r es po ns e Af te r b oo st er va cc in at io n Ka m ol th am e t al .22 Ra nd om ize d, op en -la be l p ha se -II cl in ic al tr ia l 70 3 PC EC V In tra de rm al (i) 0 .1 m L on d ay s 0 a nd 2 8; a nd (ii ) 0 .1 m L on d ay s 0 , 7 a nd 2 8 N D (i) 1 0. 76 (G M T; ra ng e: 1 .8 7– 37 ); an d (ii ) 2 2. 12 (G M T; ra ng e: 2. 13 –1 99 ) – b ot h m ea su re d 14 d ay s a fte r r ec ei vi ng 0 .1 m L PC EC V bo os te r v ac ci na tio n on da ys 3 65 a nd 3 68 Se ro co nv er sio na oc cu rre d w ith in 14 d ay s o f b oo st er va cc in at io n in a ll va cc in ee s w ho re ce iv ed tw o or th re e do se s o f p re - ex po su re p ro ph yl ax is Kh aw pl od e t a l.2 5 an d Kh aw pl od et a l.2 3 Ra nd om ize d, pr os pe ct iv e 96 a nd 5 2 PV RV a nd PC EC V In tra de rm al a nd in tra m us cu la r (i) 0 .1 m L PV RV in tra de rm al ly a t tw o sit es o n da ys 0 , 7 a nd 2 8; (ii ) 0 .1 m L PV RV in tra de rm al ly at tw o sit es o n da ys 0 , 3 a nd 7 ; (ii i) 1. 0 m L PV RV in tra m us cu la rly at o ne si te o n da ys 0 , 3 a nd 7 ; (iv ) 0 .1 m L PV RV in tra de rm al ly at tw o sit es o n da y 0; (v ) 0 .1 m L PV RV in tra de rm al ly a t t w o sit es on d ay s 0 , 3 a nd 7 a nd a t o ne si te on d ay s 2 8 an d 90 ; a nd (v i) 0. 1 m L PC EC V in tra de rm al ly a t t w o sit es on d ay s 0 , 3 a nd 7 a nd a t o ne si te on d ay s 2 8 an d 90 (i) 0 .9 6 (G M T) o n da y 36 0; (i i) 1. 12 (G M T) on d ay 3 60 ; ( iii ) 0 .9 7 (G M T) o n da y 36 0; (iv ) 0 .4 1 (G M T) o n da y 36 0; (v ) 5 .8 4 (G M T) o n da y 28 ; a nd (v i) 5. 96 (G M T) o n da y 28 (i) 4 9. 39 (G M T) o n da y 37 4; (ii ) 1 05 .0 8 (G M T) o n da y 37 4; (ii i) 12 5. 00 (G M T) o n da y 37 4; (i v) 5 1. 96 (G M T) o n da y 37 4; (v ) N D ; a nd (v i) N D – a ll m ea su re d af te r b oo st er va cc in at io n w ith 0 .1 m L PV RV in tra de rm al ly a t t w o sit es o n da ys 36 0 an d 36 3 Se ro co nv er sio na oc cu rre d af te r bo os te r v ac ci na tio n w ith a ll re gi m en s; th e tw o st ud ie s u se d th e sa m e re gi m en s a nd re po rt ed th e sa m e da ta M ill s e t a l.3 3 Ca se se rie s 42 0 H D CV In tra de rm al 0. 1 m L at tw o sit es o n da ys 0 an d 7 > 0 .5 in 9 4. 5% o f va cc in ee s o n da y 28 N D Se ro co nv er sio na oc cu rre d in 9 4. 5% o f va cc in ee s b y da y 28 fo llo w in g a tw o- vi sit p re -e xp os ur e pr op hy la xi s r eg im en (c on tin ue s. . . ) Jocelyn A Kessels et al.Pre-exposure rabies prophylaxis Systematic reviews 219B Bull World Health Organ 2017;95:210–219C | doi: http://dx.doi.org/10.2471/BLT.16.173039 Re fe re nc e St ud y t yp e No . o f s tu dy pa rt ici pa nt s Va cc in e Va cc in at io n ro ut e Re gi m en An tib od y t itr e (IU /m L) Co m m en ts Pr im ar y r es po ns e Af te r b oo st er va cc in at io n Kh aw pl od e t a l.2 4 Ab br ev ia te d, pr os pe ct iv e 10 9 PC EC V In tra de rm al a nd in tra m us cu la r (i) 0 .1 m L in tra de rm al ly o n da ys 0 , 7 a nd 2 1, fo llo w ed b y a 1. 0- m L in tra m us cu la r b oo st er on d ay s 3 60 a nd 3 63 ; ( ii) 0 .1 m L in tra de rm al ly o n da ys 0 , 7 a nd 2 1, fo llo w ed b y a 0. 1- m L in tra de rm al bo os te r a t f ou r s ite s o n da y 36 0; (i ii) 0 .1 m L in tra de rm al ly at tw o sit es o n da y 0, fo llo w ed by a 1 .0 -m L in tra m us cu la r bo os te r o n da ys 3 60 a nd 3 63 ; (iv ) 0 .1 m L in tra de rm al ly a t t w o sit es o n da y 0, fo llo w ed b y a 0. 1- m L in tra de rm al b oo st er at fo ur si te s o n da y 36 0; (v ) 1 .0 m L in tra m us cu la rly o n da y 0, fo llo w ed b y a 1. 0- m L in tra m us cu la r b oo st er o n da ys 36 0 an d 36 3; a nd (v i) 1. 0 m L in tra m us cu la rly o n da y 0, fo llo w ed b y a 0. 1- m L in tra de rm al bo os te r a t f ou r s ite s o n da y 36 0 (i) 0 .4 9 (N Ab ); (ii ) 0 .3 0 (N Ab ); (ii i) 0. 15 (N Ab ); (iv ) 0 .1 0 (N Ab ); (v ) 0 .0 8 (N Ab ); an d (v i) 0. 11 (N Ab ) – al l m ea su re d be fo re bo os te r v ac ci na tio n on d ay 3 60 (i) 1 1. 27 (N Ab ); (ii ) 4 2. 49 (N Ab ); (ii i) 9. 71 (N Ab ); (iv ) 1 1. 96 (N Ab ); (v i) 10 .1 3 (N Ab ); an d (v i) 13 .3 3 (N Ab ) – a ll m ea su re d 7 da ys a fte r bo os te r v ac ci na tio n Se ro co nv er sio na oc cu rre d w ith in 7 da ys o f b oo st er va cc in at io n fo r a ll re gi m en s a ss es se d La u & H oh l28 Ca se se rie s 54 PC EC V In tra de rm al 0. 1 m L at tw o sit es o n da ys 0 an d 7 > 0 .5 in 9 4. 4% o f va cc in ee s o n da y 28 N D Se ro co nv er sio na oc cu rre d in 9 4. 4% o f va cc in ee s b y da y 28 W on gs ar oj e t a l.4 1 Ra nd om ize d, pr os pe ct iv e 55 PV RV In tra de rm al a nd in tra m us cu la r (i) 0 .1 m L in tra de rm al ly a t t w o sit es o n da ys 0 a nd 2 1; a nd (ii ) 0 .5 m L in tra m us cu la rly o n da ys 0, 7 a nd 2 1 (i) 4 .5 1 (N Ab ); an d (ii ) 6 .7 4 (N Ab ) – b ot h m ea su re d on d ay 3 5 (i) 1 4. 38 (G M T) ; a nd (i i) 14 .0 6 (G M T) – b ot h m ea su re d 14 d ay s af te r b oo st er v ac ci na tio n w ith 0. 1 m L PV RV in tra de rm al ly o n da ys 3 60 a nd 3 63 Se ro co nv er sio na oc cu rre d w ith in 14 d ay s o f b oo st er va cc in at io n w ith b ot h re gi m en s Je lin ek 20 Ra nd om ize d, ob se rv er -b lin de d, m ul tic en tre 66 1 PC EC V In tra m us cu la r (i) 1 .0 m L on d ay s 0 , 7 a nd 28 , w ith st an da rd Ja pa ne se en ce ph al iti s v ac ci ne re gi m en ; (ii ) 1 .0 m L on d ay s 0 , 3 a nd 7 , w ith ac ce le ra te d Ja pa ne se e nc ep ha lit is va cc in e re gi m en ; a nd (i ii) 1 .0 m L PC EC V al on e on d ay s 0 , 7 a nd 2 8 > 0 .5 in 9 7– 10 0% o f va cc in ee s o n da y 57 N D Se ro co nv er sio na oc cu rre d in 9 7– 10 0% of v ac ci ne es b y da y 57 Br ow n et a l.1 5 Co ho rt st ud y 12 PV RV (b oo st er do se ) In tra de rm al Pe op le w ith a n an tib od y tit re < 0. 5 IU /m L fo llo w in g in iti al p re - ex po su re p ro ph yl ax is re ce iv ed on e bo os te r d os e af te r 2 y ea rs to gi ve a to ta l v ac ci ne d os e ≥ 2 IU 0. 18 (m ea n) b ef or e bo os te r 17 .3 3 (m ea n) a fte r b oo st er Se ro co nv er sio na oc cu rre d in a ll va cc in ee s w ho re ce iv ed ≥ 2 IU o f va cc in e HD CV : h um an d ip lo id c el l v ac ci ne ; G M T: ge om et ric m ea n tit re ; N Ab : n eu tra liz in g an tib od y; N D : n ot d et er m in ed ; P CE CV : p ur ifi ed c hi ck e m br yo c el l v ac ci ne ; P VR V: p ur ifi ed V er o ce ll ra bi es v ac ci ne . a Se ro co nv er sio n w as d efi ne d as a n an tib od y tit re > 0. 5 IU /m L. (. . . co nt in ue d) 219C Systematic reviews Pre-exposure rabies prophylaxisJocelyn A Kessels et al. Bull World Health Organ 2017;95:210–219C| doi: http://dx.doi.org/10.2471/BLT.16.173039 Table 7. Booster rabies vaccination recommendations, systematic review of the literature, 2007–2016 Reference Study type No. of participants Vaccination regimen Antibody titre (IU/mL) Conclusion Brown et al.16 Retrospective cohort study 89 Intradermal pre-exposure prophylaxis ≥ 0.5 after a mean of 5 years (range: 1–12) in 100% of vaccinees who received ≥ 0.6 mL of vaccine over two or three visits Intradermal pre-exposure prophylaxis with 0.6 mL of vaccine over three visits could extend the interval before booster vaccination to 10 years Lim & Barkham,29 Cohort 1 Retrospective cohort study 66 Three doses of PVRV pre- exposure prophylaxis > 0.5 in 60.6% of vaccinees after 1 year Serological surveillance or a booster vaccination 1 year after primary pre-exposure prophylaxis is advised for people in high-risk occupations Lim & Barkham,29 Cohort 2 Retrospective cohort study 15 Four doses: three of pre- exposure prophylaxis and one booster dose given after a median of 10 years (range: 3–18) > 0.5 in 100% of vaccinees after a median of 10 years (range: 3–18) Serological surveillance or a booster vaccination 1 year after primary pre-exposure prophylaxis is advised for people in high-risk occupations Cunha et al.,18 Group 1 Randomized controlled study 65 Intradermal pre-exposure prophylaxis > 0.5 in 97% of vaccinees after a mean of 10 days and > 0.5 in 20–25% after a mean of 180 days Serological testing after the third dose of pre-exposure prophylaxis is unnecessarya Cunha et al.,18 Group 2 Randomized controlled study 62 Intramuscular pre- exposure prophylaxis > 0.5 in 100% of vaccinees after a mean of 10 days and > 0.5 in 63–65% after a mean of 180 days Serological testing after the third dose of pre-exposure prophylaxis is unnecessarya Sudarshan et al.,38 Group 1 Literature review 577 Pre-exposure prophylaxis > 0.5 in 100% after a mean of 3 months It may be safe not to administer postexposure prophylaxis in healthy individuals re-exposed to rabies within 3 months of pre-exposure or previous postexposure prophylaxis Sudarshan et al.,38 Group 2 Literature review 2795 Postexposure prophylaxis > 0.5 in 99.9% after a mean of 3 months It may be safe not to administer postexposure prophylaxis in healthy individuals re-exposed to rabies within 3 months of pre-exposure or previous postexposure prophylaxis PVRV: purified Vero cell rabies vaccine. a This study did not follow up study participants 1 year after pre-exposure prophylaxis or simulate responses to postexposure prophylaxis.