WORLD HEALTH ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE
REGIONAL OFFICE FOR THE WESTERN PACIFIC BUREAU REGIONAL DU PACIFIQUE OCCIDENTAL
REGIONAL COMMn:fEE Forty-seventh session Seoul 9-13 September 1996 Provisional agenda item II
WPR/RC47/8 Rev. I
2 September 1996 ORIGINAL: ENGLISH
ERADICATION OF POLIOMYELITIS IN THE REGION:
PROGRESS REPORT
This annual progress report details the current status of the campaign to eradicate poliomyelitis in the Region. As at I September 1996, only 70 cases that meet the clinical criteria for poliomyelitis, including only four indigenous and three imported wild poliovirusassociated poliomyelitis cases, had onset of paralysis in 1996. Considerable progress has been made in both the reliability and timeliness of virological surveillance. The Regional Commission for the Certification of Poliomyelitis Eradication in the Western Pacific Region has held its first meeting, ratifying a plan of action and recommending the establishment of
-,
national committees. The future activities of the programme are described, with emphasis on improving the quality of surveillance and laboratory performance, and development of special strategies to reach high-risk popUlations, including in border areas, during national immunization days. The Regional Committee is asked to take note of the report, to maintain its commitment to arresting all transmission of the wild poliovirus, and to ensure that all countries and areas implement the necessary steps to certify eradication of the disease from the Region.
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1. INTRODUCTION
At its thirty-ninth session in September 1988, the Regional Committee for the Western Pacific adopted resolution WPRlRC39.RI5 on the eradication of poliomyelitis in the Region by 1995. Resolution WPRlRC41.R5 called for an annual report on eradication, and WPRlRC42.R3 and WPRlRC44.R4 proposed ways to further accelerate the programme. Rapid progress has since been made towards the eradication of poliomyelitis in the Region.
2. PRESENT EPIDEMIOLOGICAL SITUATION
In 1995, six countries continued to report poliomyelitis cases (Cambodia, China, the Lao People's Democratic Republic, Papua New Guinea, the Philippines and Viet Nam). More than 5600 cases of acute flaccid paralysis (AFP) were reported in 1995. Of these, 474 cases met clinical criteria for poliomyelitis, and 31 of those 474 cases were associated with wild poliovirus (see Table 1). Most of the cases meeting clinical criteria are actually not true poliomyelitis, but are due to diseases that clinically resemble poliomyelitis (such as GuiIlain Barre syndrome with residual paralysis). This is especially the case in China. For 1996, as at 1 September, only 70 cases with onset in 1996 have been reported which meet the clinical criteria for poliomyelitis, of which only seven have been confirmed as being associated with wild poliovirus (four indigenous cases and three imported cases). Circulation of wild poliovirus is now confmed to the Mekong Delta of Cambodia and Viet Nam. In 1995, 30 out of the 31 virologically confirmed cases (Le. wild poliovirus was isolated in stool samples) originated from that area. The other wild poliovirus case was imported into China, which highlights the risk of transmission across borders with other areas where the disease is still endemic.
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WPRlRC4718 Rev. 1
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3. PROGRAMME ACTIVITIES
3.1
Strengthening of routine EPI activities Routine immunization activities continue to be a cornerstone of the poliomyelitis eradication
programme. (Figure I).
Routine oral poliovirus vaccine (OPV) coverage remained at 93% during 1995
3.2
Supplementary immunization activities A total of 18 national immunization days have been conducted in the Region from 1992 to .....
1995 (see Table 2). In the low transmission season of 1995-1996, countries made great efforts to ensure high quality national immunization days. This was done by focusing on areas and age groups at high risk for ongoing poliovirus transmission and by improving social mobilization. Cambodia has reduced its number of reported poliomyelitis cases by almost sixty percent (from 296 to 124 cases) after just one year of national immunization days, while simultaneously greatly improving surveillance. There will be a gradual shift from national to subnational immunization days, focusing on high risk areas and populations, according to the quality of the surveillance system and the epidemiological situation in each country.
3.3
Poliomyelitis surveillance In 1995, over 5600 cases of acute flaccid paralysis were reported throughout the Region. This
was an increase of almost 50% over the 1994 total. Almost 100% of these cases were investigated. At least one stool sample was sent for analysis in 90% of the reported cases, and two stool samples were taken within 14 days of onset for 70% of the cases. For 1996, as at 1 September, the proportion of acute flaccid paralysis cases with at least one stool sample taken was also 90%, and two samples were taken within 14 days for 73% of the cases. In 1995, only 474 cases of acute flaccid paralysis met clinical criteria for poliomyelitis. This is a decrease of 32% compared to the 1994 total of 699 cases, and a decrease of 92% when compared to
WPRlRC4718 Revo1 page 4
the figures of 1990. Figure 2 illustrates the geographical distribution of cases meeting clinical criteria for poliomyelitis in 1990 and in 1995. Only 31 of theOmore than 5600 cases of acute flaccid paralysis reported confirmed as poliomyelitis by wild virus isolation. All eight countries that have recently reported poliomyelitis now have well-established national acute flaccid paralysis surveillance systems. Improvements in completeness and timeliness of acute flaccid paralysis surveillance have been made, while the total number of poliomyelitis cases reported and those confirmed by wild poliovirus isolation has diminished (see Figure 3). In April 1996, the Regional Commission for the Certification of Poliomyelitis Eradication in the Western Pacific Region met for the first time in Canberra, Australia. The Commission comprises eight members who serve in their individual capacity as experts in virology, neurology, epidemiology and public health management. At its first meeting, the Commission set criteria, strategies and a plan of action for the certification of poliomyelitis eradication in the Western Pacific Region. It was decided that criteria for the certification of poliomyelitis eradication will include: III
1995 were
(l)
No detection of indigenous wild poliovirus transmission for a period of at least three years,
during which surveillance has been at a performance level needed for certification. (2) Validation and submission of the certification documentation required by the Regional
Commission by a national certification committee in each country. (3) Presence of appropriate measures to detect and respond to importation of wild poliovirus. The following steps were outlined with respect to the process of certification: (l)
All Member States reporting zero cases of poliomyelitis should establish a national
certification committee by December 1996. (2) (3) Other countries should establish committees by the end of 1997. Non-poliomyelitis-endemic countries should review the plan of action and report their
proposed activities and problems to the Regional Commission by mid-1997.
WPRlRC4718 Rev.1 pageS
(4) (5)
All non-poliomyelitis-endemic countries should submit documentation by 1998. All poliomyelitis-endemic countries should submit documentation by 1999. The Pacific island countries and areas will have a subregional certification committee formed
by the end of 1996 to include 20 countries and areas as a single epidemiological block. Their first briefmg report is expected in 1997.
3.5
Vaccine quality The regional plan of action for achieving self sufficiency in vaccine production and supply is
being implemented. The plan aims at strengthening local vaccine production and national capabilities in quality control. It also supports continued cooperation between national governments and the international community. in procuring vaccines. Ultimately, this should lead to a sustainable supply of adequate quantities of potent, good-quality and safe vaccines. Under the plan of action, the Regional Office for the Western Pacific is actively collaborating with centres of excellence for vaccine production and quality control. Technical support is being provided to China. the Philippines and Viet Nam. strengthening of national quality control authorities. 3.6 Resource requirements Although the governments of the countries concerned provide the major part of the resources required for the expanded programme on immunization and poliomyelitis eradication, international support has been instrumental in the successful implementation of poliomyelitis eradication activities in the Region. This support is related to vaccine supply and operational costs. The role of the many partners in funding the programmes to eradicate poliomyelitis is gratefully acknowledged, particularly UNICEF, the governments of Australia. Canada, France, Japan, Malaysia. Republic of Korea. and United States of America through the Centers for Disease Control in Atlanta, and Rotary International and Rotary International District 2650 of Japan. This important support will still be needed until eradication is certified throughout the Region. In 1996, the major focus will be on the
WPRlRC47/8 Rev.! page 6
3.6.1
Vaccine From 1992 to 1996, a total of US $32.2 million has been provided by international partners for
the purchase of oral poliovirus vaccine for supplementary immunization (see Figure 4).
3.6.2
Operational sURP0rt In addition to the provision of vaccine, since 1992, a total of US$ II million has been
committed by partners for staff, supplies and equipment, and operational costs for surveillance and national immunization days.
3.7
Major issues in poliomyelitis eradication and action being taken ACTION BEING TAKEN
MAJOR ISSUES Quality of supplementary immunization Wild virus transmission among non-immunized children despite high reported NID coverage. Acute flaccid paralysis and laboratory surveillance • Inadequate performance of laboratories in regional network.
•
Mobile teams have been created and other new strategies are being implemented to find and immunize children in high-risk areas New laboratory equipment has been supplied or ordered Consultants are reviewing performance and training laboratory staff Laboratory performance indicators are being more closely monitored at central level Computerized data transfer is being improved Active surveillance for acute flaccid paralysis and measles has been introduced Active surveillance is being intensified on both sides of the border Improvements are being made in the quality of NIDs in border areas, with extra posts, extra staff, mobile teams Simultaneous supplementary immunization activities on both sides of border areas are being planned Continued funding support for surveillance, staff posts, and OPV is being sought from partner agencies
•
• • •
• • •
Insufficient surveillance activity in countries recently endemic for poliomyelitis Cross-border transmission of poliovirus Need to improve cross-border coordination
•
• •
• Resource availability • Obtaining resources for surveillance and supplementary immunization.
•
WPRlRC47/8 Rev.1 page 7
4. FUTURE ACTIVITIES
4.1
Supplementary immunization
Supplementary immunization activities will continue, based on each country's individual situation. Special attention will be given to the China-Myanmar border region, where one imported case was documented in 1995 and, as at I September, three in 1996. Efforts will be made to coordinate control activities, and to ensure that at least one supplementary immunization round in the 1996-1997 low transmission season will coincide in both countries. Special strategies will also be developed by countries to reach high-risk populations during national immunization days. 4.2 Laboratory and acute flaccid paralysis surveillance
A system of laboratory accreditation will be set up, based on performance. All laboratories will be monitored. Where laboratories do not perform satisfactorily, specimens from cases of acute flaccid paralysis will be sent instead to an accredited laboratory.
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WPRlRC471S Rev.l pageS
Table 1. Total AFP cases reported, showing cases meeting clinical criteria for poliomyelitis, and cases associated with wild poliovirus, 1993-1996* Western Pacific Region Total AFP cases reported 93 Cambodia China LaoPDR Malaysia Mongolia Papua New Guinea Philippines Pacific island countries VietNam Others Westem Pacific Region 135 1818 9 1 Cases meeting clinical criteria for poliomyelitis (including virologically confirmed cases) 94 % 93 95 135 538 7 0 2 0 15 296 261 6 0 0 2 10 124 165 8 0 0 1 40 16 20 1 0 0 0 4 0 29 0 70 WDd poIio'rirus isolated 93 4
Country
94 301 3096 II 17
95 181 4802 16 13 0 13 153 3 466 0 5647
% 83 2070 4
94 33 6 0 0 0 0
95 18
% 2 3• 0 0 0 0
101 0 0 0 0 7 0 157
I • 0 0 0 0 0 0 12 0 31
11 11 9
** 16 88 0 607 1 2675
*. 13 126 1 353 I 3919
44 4 271 1 2508
0 0 35
0 0 2 0 7
0 452
0 124
0 136
0 1149
0 699
0 474
0 269
0 74
Latest available data from WPRO AFP Surveillance System as at I September 1996. All cases reported by year of onset. • All wild poliovirus cases in China are imported cases ** Data not available.
Figure 1. Reported poliomyelitis cases and OPV3 coverage, 1980-1995* Western Pacific Region
14000
Poliomyelitis cases·· 94 93
OPV3 coverage (%) 100%
12000
92
93
93
93 80"1.
10000 60%
8000
6000
40"10
4000 20% 2000
0
0'10 80 81 82 83 84
85
86
117
88
89
90
91
92
93
94
95·
Year
Data source: WHOIWPRO CEIS and WPRO Poliomyelitis Surveillance Reports. ·Provisional data based on annual trends and information available as at 1 September 1996. ··Cases meeting clinical criteria for poliomyelitis (includes virologically confirmed cases).
WPRlRC4718 Rev.l page 9
Table 2. National immunization days, 1992-1996* Western Pacific Region Country Total Total subnational national immunization immunization days days I
Coverage
Other antigens
Number immunized
Cambodia China LaoP.D.R.
2 3 3
95% >80% 80%
Vitamin A
1.9 million 83 million 650000
1
Vitamin A Measles, DPT*** Diphtheria, Tetanus toxoid, Measles
2
Mongolia
0
3
97%
424 000
Papua New Guinea Philippines
1** "
0 4
>90%
Vitamin A, Tetanus toxoid, Measles Vitamin A, Tetanus toxoid, Measles
NA 9.9 million
0
VietNam
1
3
>90%
9.7 million
18 6 • F.gures as at 1 September 1996 '*One round only in August 1996; second round scheduled for September 1996. TOTAL ···diphtheria. pertussis, tetanus
105 million
triple antigen
WPRlRC4718 Rev.l page 10 Figure 2. Geographical distribution of poliomyelitis cases· in 1995 compared to 1990 Western Pacific Region
Poliomyelitis 1995 N......rorcua:
474 as at 1 JIlIy 1996
o
..
Poliomyelitis 1990 5963 .... ,.... an. . . . . . ,.,.,.. 'I .,....
'cases meeting clinical criteria for poliomyelitis (includes virologically confumed cases)
WPRlRC47/8 Rev.l page 11
Figure 3. Reported acute flaccid paralysis, cases meeting clinical criteria for poliomyelitis, and wild poliovirus associated cases, 1992-1995 Western Pacific Region 6000 5000 II1II Reported cases of acute flaccid paralysis
.... '" '" .. ... . 0 ,Q
4000
o Cases meeting 3000 2000 1000 0 1992 1993 1994 Year
= :z:
e
clinical criteria for poliomyelitis • Wild poliovirus associated cases
1995
Data source: WPRO AFP Surveillance System as at I July 1996
Figure 4. Partner support for oral poliovirus vaccine requirements, 1992-1996 Western Pacific Region
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Total: US$ 32.2 million Rotary International 34% Japan
32%
Australia 7%
United States of America 10%
UNICEF 13%
4%
Data as at 20 June 1996; includes committed as well as received funds.