Expanded programme on immunization


Technical Advisory Group (TAG) on Immunization and Vaccine Preventable Diseases in the Western Pacific Region (17th Meeting - 7-9 July 2008) - Meeting Report (Laboratory Workshop)

Publication details

Publication date: 2009



Representatives of the WHO-designated regional poliomyelitis and measles/rubella laboratories and of the Japanese encephalitis laboratory from selected countries met in Manila from 7 to 9 July 2008. The meeting also was attended by the Technical Advisory Group members, temporary advisers from the United States Centers for Disease Control and Prevention (CDC), representatives from PATH, WHO Headquarters laboratory coordinators, and WHO Western Pacific Regional Office and EPI country staff.

The objectives of the meeting were:

(1) to review the laboratory performances of Regional Reference Laboratories (RRLs) and national laboratories for polio and measles (NPLs), to maintain polio-free status and to reach the goal of measles elimination in the Region;

(2) to discuss the introduction of a new algorithm for poliovirus identification in the Region and new requirements for the measles laboratory network in the Region; and

(3) to establish the Japanese encephalitis LabNet for selected countries and to develop laboratory diagnostic capacities for JE in the Region.

The Global Polio Laboratory Network (GPLN) comprised of national, regional reference, and global specialized laboratories plays a very crucial role in the global polio eradication initiative. Besides timely identification of wild polioviruses, the rapid detection of vaccine-derived poliovirus (VDPV) that causes acute flaccid paralysis is becoming increasingly important because of polio outbreaks reported due to circulating VDPV. Since the Regional Polio Laboratory Network meeting in 2002, there have been new developments in the GPLN. A new standard WHO algorithm for poliovirus isolation and identification has been introduced into the network and should provide the results of primary isolation within 14 days of the receipt of sample in the laboratory. Further, the results of identifying a wild type or vaccine strain of poliovirus with the use of an intratypic differentiation (ITD) testing procedure should be available within seven days. Participants were briefed about these changes. Representatives from the polio network laboratories presented the country data for the period 2002-2008.

Recommendations for the polio laboratory network include: (1) the new checklists for the NPLs and RRLs should be implemented among network laboratories, including 31 provincial laboratories in China, as soon as possible. Standard operating procedures (SOPs) also should be revised to meet new requirements in the checklists; and (2) NPLs are encouraged to implement the new algorithm for virus isolation but can continue to perform the polio neutralization test in parallel to shipping the isolates to the RRL. SOPs and databases in each laboratory should be revised and implementation of the changes should be reported to the regional laboratory coordinator.

Since the measles and rubella laboratory network was established in 2004, the LabNet has played a critical role in the progress towards achieving the regional goal of measles elimination by 2012. The LabNet tested more than 110 000 serum samples in 2007 in the Western Pacific Region. All Western Pacific Region NPLs passed the proficiency test in 2007, and confirmatory testing has been implemented by many national laboratories. To cope with the increased number of confirmatory samples in the region, the national measles laboratory in Hong Kong (China) was designated as a regional reference laboratory in May 2007. Participants discussed remaining challenges for the WPR LabNet, including improving sample collection for virus detection, validation of test kits used in the subnational LabNet, and the improved timeliness and completeness of laboratory reporting. Also discussed were new requirements for the measles LabNet, including the introduction of new case-based laboratory reporting and revised accreditation checklists emphasizing the timeliness of reporting. The participants also presented their national data for the period 2004-2008.

Recommendations for the measles/rubella laboratory network include: (1) a new casebased laboratory reporting scheme should be used in all measles/rubella network laboratories (NMLs) as much as possible and network laboratories were asked to submit their monthly data for the previous month by the 10th of the month; (2) as recommended by the Global Measles Laboratory Network Meeting of September 2007, new checklists for the NMLs and RRLs that emphasize the timeliness and completeness of genotyping and sequencing of measles viruses should be used for the accreditation of network laboratories. NMLs were encouraged to submit genotype information about circulating measles and rubella strains to the WHO genotype database. This genotypic information should be shared with the regional laboratory coordinator; (3) a regular confirmatory testing mechanism for measles and rubella samples should be established for all NMLs in the Region to ensure the accuracy and quality of testing. The confirmatory results should be shared with regional laboratory coordinators. The reasons for discrepancies between the NMLs and the RRLs in the results should be sought and immediate corrective actions should be taken in the NMLs; and (4) a mechanism for sample referral among the Pacific island countries should be reviewed and reestablished in the Region. Some mechanisms to support the NMLs in priority countries should be established and maintained in the Region.

The Western Pacific Region has seven countries either known to be endemic for Japanese encephalitis (JE) or suspected to be endemic for JE. These countries include China, Cambodia, the Lao People's Democratic Republic, Malaysia, Papua New Guinea, the Philippines, and Viet Nam. However, the activities of laboratories are limited among those JE-endemic or suspected JE-endemic countries in the Region. Therefore, it was proposed to create a laboratory network for JE to improve the capability of JE case confirmation in the Region.

Recommendations for the JE laboratories in the Region include: (1) potential GSL (one), RRLs (two), and national laboratories for JE should be identified by 2008. A formal accreditation system to evaluate the laboratory performances of the network laboratories should be established in collaboration with WHO HQ and the WHO South-East Asia Regional Office (SEARO); (2) proficiency test panels for JE should be arranged for the network laboratories by 2009; (3) a training workshop for the laboratory diagnosis of JE should be organized by early 2009; and (4) laboratory capability should be established to support acute encephalitis syndrome surveillance to detect bacterial antigens as well as JE.

It was recommended that two additional laboratory network coordinators are needed for the Region, one with expertise in virology and another with expertise in bacteriology. They would be necessary to deal with the increasing number of specimens, the heightened activities of the polio and measles laboratory networks and the introduction of laboratory based surveillance for new vaccines in the Region.