(WP)CDS(P)/ICP/GPA/012-E
ENGLISH ONLY
REPORT
~RKSHOP ON SURVEILLANCE AND EPIDEMIOLOGY
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IN HIV INFECTION AND AIDS
Convened by the
REGIONAL OFFICE FOR THE WESTERN PACIFIC OF THE WORLD HEALTH ORGANIZATION
Manila, Philippines 9-12 October 1989
o1 Not for sale Printed and distributed by the Regional Office for the Western Pacific of the World Health Organization Manila, Philippines March 1990
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The views expressed in this report are those of the participants in the Workshop on Surveillance and Epidemiology in HIV Infection and AIDS and do not necessarily reflect the policies of the World Health Organization.
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This report has been prepared by the Regional Office for the Western Pacific of the World Health Organization for governments of Member States in the Region and for the participants in the Workshop on Surveillance and Epidemiology in HIV Infection and AIDS, Manila, Philippines, 9 to 12 October 1989.
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CONTENTS
1.
INTRODUCTION •••••••
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................ " " " .. " " " " " ................................ . II ••
1
1.1 Background .......................... "......
1.2 Organization of the workshop ••••• 1.3 Remarks by the Regional Director. 1.4 Objectives ................................. .. 2.
........................ ................. . ................ " ............... , ............ " .......... . "
1 1 2 2
ACTIVITIES AND FINDINGS.......................................... 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 The global challenge of AIDS.......... HIV antibody testing ... "......... ".... "....... Surveillance studies ............ ". "" .... Selec tion bias .............................. "............ t .. " It .. .. ..
• •••••••••••••••• 2 .. • " •
. .............. "..... " 3 3 3 Sampling strategies for low prevalence population.... 3
Counselling and confidentiality...................... 4 Self-teaching manual.................................. 4 Field gUidelines of HIV sentinel surveillance ••••••••••••• 5
3..
CONCLUSIONS ........................................... " .......................... " " ........................... 5
ANNEXES: ANNE:){ 1 - AGENDA" ............................... "........................ ".............. II .... "
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ANNEX 2 - LIST OF PARTICIPANTS ................................. 11 ANNEX 3 - SMALL GROUP WORKSHOP................................. 17
1.
INTRODUCTION
1.1 Background Incomplete reporting and inadequate recognition of HIV infection have resulted in an underestimation of the current and future AIDS problem in the world and in the Western Pacific Region. Moreover, information from Member States on the prevalence of HIV is the basis for developing rationally-designed national AIDS prevention and control programmes. This information is used to assess trends in infection over time , to evaluate . ~ntervention strategies and to further identify risk groups for specific intervention strategies. Fourteen countries have developed and implemented national AIDS programmes in the Region. One component of these national strategies includes surveillance. Establishing a surveillance system is a substantial challenge, however. Issues involving personal and social behaviour are of paramount importance in the transmission of AIDS. In the Region, this is further compounded by the very low prevalence of known HIV infection. The Workshop on Surveillance and Epidemiology of HIV Infection and AIDS was convened to look at the general problem of surveillance, the challenge confronting the Region and the steps necessary to implement a practical national protocol in the countries represented. 1.2 Organization of the workshop The workshop agenda is attached as Annex 1. The participants and temporary advisers were from 22 countries and areas in the Region and are listed in Annex 2. Facilitators included three temporary advisers and five WHO staff from the Regional Office and from Headquarters. Dr T. Tabua, Dr E.T. Nukuro and Dr Sulaiman Che Rus were nominated Chairman, Vice-Chairman and Rapporteur, respectively. Small group discussions were emphasized and constituted the bulk of the meeting time. This was designed to accommodate the different HIV surveillance issues confronting countries and areas of different sizes as well as the varied backgrounds of the participants. In these small groups, the participants took an active role. They used a training module for HIV surveillance, reviewed field guidelines for HIV sentinel surveillance and then drafted national protocols. Modification of the agenda, attached as Annex I, was necessary as Manila was buffeted by a typhoon on the third day of the workshop, forcing cancellation of the activities scheduled for that day.
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1.3 Remarks by the Regional Director The meeting was opened by the Regional Director, Dr S.T. Han. After summarizing the epidemiology in the Region, Dr Han noted the paucity of HIV surveillance material from the Region. Moreover, it would be vitally important that detailed information be available from groups at risk for acquiring the virus believed to cause AIDS. This material would be important to plan preventive strategies and then to assess the trends and monitor the interventions designed to reduce transmission. Dr Han personally asked the participants to work hard and return to their country and present the draft protocols which they had written during the meeting to the Ministry of Health and the National AIDS Committee. 1.4 Objectives The objectives of the workshop were: (1) (2) (3) (4) (5) to review the epidemiological situation of AIDS and HIV infection and the surveillance activities being carried out; to exchange information and experiences on the surveillance of AIDS and HIV infection: to identify the problems encountered in surveillance activities: to discuss and find ways to improve or solve problems in surveillance; to formulate draft plans to implement surveillance activities.
2.
ACTIVITIES AND FINDINGS
The first day of the workshop, held in plenary sessions, consisted of several presentations. In this way topics were introduced for more detailed discussions in the small working groups. 2.1 The global challenge of AIDS
The global challenge of AIDS and the regional epidemiological situation were reviewed. With less than 1% of the cases reported from Asia and the Pacific and a total of 1761 cases reported as of 1 October 1989, the WHO Western Pacific Region has an opportunity and a challenge to prevent the spread of HIV. The situation could be better understood if the number of people infected with HIV could be estimated for each country in the Region. To date, the available data on HIV infection is limited. Two reasons are especially important: firstly, groups at risk are often difficult to identify and test; and secondly, selected effective surveillance studies have not been conducted.
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Countries and areas are planning, as part of the National AIDS Programme, to develop surveillance strategies for HIV. This will allow them to assess the current Situation, monitor trends and evaluate the effectiveness of HIV prevention and control activities. 2.2 HIV antibody testing One of the challenges of AIDS in the Region is to accurately estimate the very low prevalence rate. There is an attendant problem _ despite very good HIV antibody tests there are many false positive laboratory results when tests are done in low prevalence areas. The different testing options of ELISA, immunofluorescence, particle agglutination and Western Blot were briefly described. The specificity and sensitivity of each test were viewed from the perspective of known field conditions throughout the Region. 2.3 Surveillance studies The issue of surveillance was considered by reviewing the objectives of surveillance testing and then looking at different ways these can be achieved. Since one of the objectives of HIV testing is to assess trends, the best surveillance strategy would include a systematic approach; in the Region this should be done selectively and therefore the approach should also be focused towards the groups at risk. An example of this strategy is a sentinel surveillance scheme: serial testing is done on high risk groups on a regular basis USing the same selection criteria for testing (e.g. first time visitors to STD clinics). One additional adVantage, compared with other design options such as a general population study or a cohort study, is the relatively low cost of sentinel surveillance. 2.4 Selection bias In any surveillance system there are problems of data collection and attendant b~ases. While information can be collected from different sources such as hospital records and morbidity reports, this information may not accurately represent the population under study. For example, of patients visiting sexually transmitted disease (STD) clinic it is more likely to see men than women even though infection rates of HIV among heterosexuals are expected to be equal. 2.5 Sampling strategies for low prevalence population One of the most difficult problems facing epidemiologists in AIDS is estimating the denominator: what is the size of the population that is to be measured for HIV prevalence. It was noted that this is difficult when describing sexual behaviour or intravenous drug use. After reviewing the available laboratory tests and surveillance strategies, the problem of sampling in low prevalence populations was introduced to the plenary session. Because the prevalence is estimated in the Region to be between 0.01% and .001%, to obtain a statistical confidence of 95% (A error) with study power of 20% (B error), sample population studies would have to be in thousands and tens of thousands. Instead of using statistical theory, based on the central limit theorem,
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an alternative 1s to use Lot Quality Assurance Sampling (LQAS). This is based on probability theory. The LQAS method allows for a desired confidence level of 80%-95% while sampling populations from roughly 1001500 people. The limitation of this approach is that the conclusions drawn using this method are more restricted. For example, if a 90% confidence interval is used in a population sampled of 531, and two or fewer HlV sera are identified, the following conclusion can be drawn: with 90% confidence we can say that the prevalence of HIV infection is 1% or less (data taken from tables). However, if three positive sera are found then we cannot say with 90% confidence that the prevalence of HlV infection is less than 1%. No more can be said unless another sample population is tested. 2.6 Counselling and confidentiality Counselling and issues related to confidentiality were discussed. This is a vital part of prevention and control strategies for AIDS. It is especially important when associated with voluntary testing or other forms of testing that are not anonymous and unlinked. Counselling should be provided before and after HlV testing for surveillance. The purpose of the test and a detailed explanation of both a positive and a negative test result should be included in the strategies for HlV surveillance. 2.7 Self-teaching manual The facilitators, temporary advisers and secretariat worked with the participants in small groups (primarily divided on the basis of geographic proximity and country size). See Annex 3 for the list of groups. The self-teaching manual on the surveillance of HlV infection developed by the Epidemiological Support and Research Unit of the WHO Global Programme on AIDS was used as the resource document to enable the participants to discuss from the country perspective: a. b. c. d. the laboratory assessment of the presence of HlV infection; the limitations of the HlV antibody tests and their importance when considering the objectives of HlV testing programme; the importance of confidentiality and its relevance to participation bias; the variable distribution of HlV within community groups and within countries, and how this will affect the HIV surveillance programme development and implementation; sentinel surveillance.
e.
The group sessions lasted most of the second day. Facilitators' guidelines and questions were employed; the participants were encouraged to describe the challenges they foresaw in developing a national surveillance scheme. The different levels of knowledge of the participants, the perceived importance of HIV to their communities, and
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the. varying levels of ~IV surveillance programmes provided a broad range of ~ssues and ~erspect~ves :or discussion. For example, the logistic issues of ongo~ng HIV surve~llance programme implementation were described by Pattern I countries; Pattern III countries described the challenges of surveillance facing countries with no cases of AIDS reported. 2.8 Field gUidelines of HIV sentinel surveillance On the last day the participants developed protocols for HIV surveillance in their country using the WHO Field Guidelines for HIV sentinel Surveillance as the resource document. The facilitators discussed with the participants the following: (a) (b) determination of objectives; selection of sentinel population: (i) sentinel sites, (ii) sampling scheme, (iii) sample size; operational and logistic procedures; minimum data required; management and use of collected data.
(c) (d) (e)
The revised worksheets in the Field Guidelines were particularly useful for the development of surveillance objectives, and selection of sentinel populations and sites. The protocols were limited to the methodology required, and it became clear that for some countries sentinel surveillance was already occurring in an adhoc manner while for others it would not be feasible in the near future for logistic reasons and because of (small) population size. The most difficult issues were: what data is needed and how the community should be informed. Other issues were the confusion that arises between the availability of diagnostic testing and testing for surveillance; sampling frequency; intervention; and the practical considerations of who collects the blood, transport, testing technology, data storage, confidentiality and resources. The difficulty of obtaining political commitment to make HIV surveillance a priority where there were limited resources, was also considered a major problem. This is particularly true when effective surveillance mechanisms are not in place for other infectious diseases which are felt to be more pressing. There was support from the participants for the importance of HIV surveillance and the group protocols produced will provide a framework within which an effective surveillance and political commitment for surveillance can be developed in their respective countries.
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3.
CONCLUSIONS
On the basis of the above proceedings of the workshop, the following conclusions were reached by the participants: (1) The predictive value of laboratory tests for HIV infection is an important consideration when choosing the population to be tested. Predictive values of laboratory tests for HIV infection vary directly with the estimated prevalence of HIV infection in that population. In a population with a very low prevalence the positive predictive value of a test is not very good; a positive test will reflect the occurrence of falsely positive test results in an unacceptably high percentage of cases. This occurs in HIV-Ab testing even though the tests are very specific. This problem can be overcome by selecting populations that are at a higher risk for HIV infection. This has important implications for surveillance, counselling and treatment strategies and will need careful consideration. (2) Confidentiality of the results is an important issue when testing individuals for serological markers of HIV infection. This applies equally to circumstances where the objective of HIV testing is surveillance, case identification, transfusion safety, or any of the above in combination. From an epidemiological perspective, unless confidentiality is taken into account, the occurrence of participation bias (distortion of collected data as a result of the likelihood of having HIV infection differing between those who choose to participate in an HIV testing programme, and those who choose not to participate) may make the collected data very difficult to interpret. (3) Confidentiality of HIV test results is also vital for retaining community support for HIV and AIDS prevention and control programmes. The legal and ethical issues relevant to testing individuals for serological markers of HIV infection should be thoroughly discussed in the social and cultural context of the country where an HIV testing programme is to be implemented. (4) Surveillance of HIV infection is only one component of HIV and AIDS prevention and control programmes. The prevention and control of HIV and AIDS is one component of public health. Resources allocated to HIV surveillance should be commensurate with the needs of all the strategies of a comprehensive HIV and AIDS prevention and control programme, as well as the needs of public health in that country as a whole. (5) There remains a need for additional information on the patterns of behaviour placing persons at risk of HIV infection in the countries and states of Asia and the Pacific. Furthermore, continued efforts directed at identifying and establishing contact with groups of individuals practising behaviour which places them at risk of HIV infection should be pursued as a priority. KABP surveys of intravenous drug use, sexual practices, or both, will be an important adjunct to this effort.
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_ ANNEX 1
PROVISIONAL AGENDA
1. OPENING CEREMONY 2. ADOPTION OF THE AGENDA 3. THE GLOBAL CHALLENGE OF AIDS AND THE EPIDEMIOLOGY OF HIV INFECTION 4. SUMMARY OF HIV Ab TESTING TECHNIQUES 5. SURVEILLANCE, DESIGN OPTIONS INCLUDING SENTINEL SURVEILLANCE, FOR HIV INFECTION 6. DATA COLLECTION AND BIAS IN EPIDEMIOLOGIC DATA 7. SELECTED COUNTRY PRESENTATIONS ON SURVEILLANCE OF HIV INFECTION AND AIDS 8. COUNSELLING AND CONFIDENTIAUTY 9. SAMPUNG STRATEGIES FOR LOW PREVALENCE POPULATIONS 10. INTRODUCTION TO SELF TEACHING MANUAL ON THE SURVEILLANCE OF HIV INFECTION AND AIDS 11. SURVEILLANCE OF HIV INFECTION AND AIDS SMALL WORKING GROUPS USING THE SELF TRAINING MANUAL 12. DEMONSTRATION AND INTRODUCTION TO "EPI INFO" COMPUTER SOFl'WARE 13. INTRODUCTION TO DRAFTING OF NATIONAL PROTOCOL FOR SURVEILLANCE OF HIV INFECTION AND AIDS 14. DRAFl'ING NATIONAL PROfOCOLS AND PLAN OF ACTION SMALL WORKING GROUPS USING THE FIELD GUIDELINES 15. PRESENTATION OF SELECTED NATIONAL PROfOCOLS 16. REVISING NATIONAL PROTOCOLS FOR HIV INFECTION AND AIDS SURVEILLANCE 17. WORKSHOP EVALUATION 18. CLOSING CEREMONY
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ANNEX 2
UST OF PARTICIPANTS, TEMPORARY ADVISERS, OBSERVERS AND SECRETARIAT
1.
PARTICIPANTS
CHINA
Dr Zeng Guang Virologist Institute of Epidemiology Beijing Dr Wang Hui Medical Officer, Chief Doctor Department of Epidemic Prevention and Health Ministry of Public Health Bei jing
FIJI
Dr B.P. Ram
Principal Medical Officer Ministry of Health Tamavua
FRENCH POLYNESIA
Professor Claude Gras Chief, Medical Services Papeete
GUAM
Dr Aurora Cabanero Infection Control Office GMHA, 850 Gov. Carlos Camacho Road Oka Tamuning
KIRIBATI
Dr Sirambiata K. Metai c/o Ministry of Health and Family Planning P.O. Box 268 Bikenibeu Tarawa
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Annex 2
LAO PEOPLE I S DEMOCRATIC REPUBUC
Mr Khanthanouvieng Xayavong c/o Ministry of Health and Social Affairs Vientiane
Dr Sithat Insisiengmay c/o Ministry of Health and Social Affairs Vientiane
MACAO
Dr Maria Fernanda Ferreira Head Public Health Laboratory Department of Health Services Av. Conselheiro Ferreira de Almeida Macao
MALAYSIA
Dr Su1aiman Che Rus Senior Medical Officer of Health Epidemiology Unit Ministry of Health Kuala Lumpur
MICRONESIA, FEDERATED STATES OF
Mr Ben Jesse Health Specialist/AIDS Project Coordinator Department of Human Resources FSM National Government Ko1onia Dr J. Ferrand-Coustenoble Chef de Service des Actions Sanitaires de 1a Directeur Territorial des Affaires Sanitaires et Socia1es B.P. 3278 Noumea
NEW CALEDONIA
NORTHERN MARIANA ISLANDS
Dr Larry Hocog Public Health Officer P.O. Box 209, CHRB Saipan
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Annex 2 PAPUA NEW GUINEA Dr Tompkins Tabua Senior Medical Officer, STD/AIDS Department of Health Boroko
PHILIPPINES
Dr Virginia Basaca-Sevi11a AIDS Consultant Department of Health Manila
REPUBUC OF KOREA
Dr Myoung-don Oh Public Health Doctor Division of Epidemiology & Surveillance 57-11 Cheungdam-dong Kangnam-gu Seoul 135-100
SAMOA
Mrs Sally Betham Assistant Director of Nursing; Member of AIDS National Committee Apia
SOLOMON ISLANDS
Dr E.T. Nukuro Acting Under Secretary (Health Improvement) Ministry of Health and Medical Services Honiara
TONGA
Dr S. Ti1iti1i Pu10ka Chief Medical Officer - Public Health Ministry of Health Nuku'a1ofa
VANUATU
Dr Willie Tokon Anaesthetist Vila Central Hospital Private Bag Vila
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Annex 2
VIET NAM
Dr Bo Xuan My Deputy Head Department of Infectious Diseases Hanoi Centre Hospital Hanoi
2.
TEMPORARY ADVISERS
Dr Arvind Patel Principal Medical Officer (Communicable Diseases) Department of Health P.O. Box 5013 Wellington New Zealand Dr K. Soda Department of Public Health Yokohama City University School of Medicine 3-9 Fukuura, Kanazawa-ku Yokohama 236 Japan Dr Eng-Kiong Yeoh Consultant Physician Medical Unit 'A' Queen Elizabeth Hospital Wylie Road Kowloon Hong Kong
3.
OBSERVERS
COLLEGE OF PUBUC HEALTII
Dr C. Ancheta Faculty Member, Department of Epidemiology and Biostatistics College of Public Health University of the Philippines Manila Dr N. Barzaga Faculty Member, Department of Medical Microbiology College of Public Health University of the Philippines Manila
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Annex 2 Me R.B. Gose Faculty Member, Department of Medical Microbiology College of Public Health University of the Philippines Manila CLARK AIR BASE
Dr Fran Agresti
Flight Surgeon Clark Air Base Angeles City SOUTH PACIFIC CCl1MISSION Dr Francois Bach Epidemiologist South Pacific Commission B.P. DS Noumea CEDEX New Caledonia
4.
SECRETARIAT
Dr Paul Sato Global Programme on AIDS WHO Headquarters Geneva
Dr B. Nkowane Global Programme on AIDS WHO Headquarters Geneva Dr V. Rajcoomar Global Programme on AIDS WHO Headquarters Geneva Dr A. Jha
Global Programme on AIDS WHO Headquarters Geneva
Dr G. Petersen Regional Adviser in AIDS WHO Regional Office for the Western Pacific United Nations Avenue Manila
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Annex 2
Dr J.W. Peabody Medical Officer Regional Programme on AIDS WHO Regional Office for the Western Pacific United Nations Aveue Manila Dr A. Romualdez
Acting Chief, Human Resource Development WHO Regional Office for the Western Pacific United Nations Avenue Manila Dr J. Robey Regional Adviser in Health Information WHO Regional Office for the Western Pacific United Nations Avenue Manila
Mr M. Lynch Laboratory Scientist Regional Programme on AIDS WHO Regional Office for the Western Pacific Manila Dr D.J. Goodwin Short-term Consultant Regional Programme on AIDS WHO Regional Office for the Western Pacific Manila Dr Rabin Sarda Short-term Consultant (Epidemiology) WHO Representative's Office Suva
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SMALL GROUP WORKSHOPS
GROUP 1 (6) Location: Committee Room 1
GROUP 2 (7) Location: Committee Room 2
FEDERATED STATES OF MICRONESIA GUAM NORTHERN MARIANA ISLANDS PAPUA NEW GUINEA SOLOMON ISLANDS OBSERVER FROM SOUTH PACIFIC COMMISSION
FRENCH POLYNESIA MALAYSIA NEW CALEDONIA LAO PEOPLE'S DEMOCRATIC REPUBliC VIET NAM
GROUP 3 (6) Location: Lounge
GROUP 4 (6) Location: Conference
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KIRIBATI SAMOA TONGA VANUATIJ OBSERVER FROM THE PHILIPPINES
CHINA MACAO PHILIPPINES REPUBliC OF KOREA OBSERVER FROM US AIR BASE (DR F. AGRESTI)
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