WHO's Initiatives to Control Vaccine Preventable Diseases (VPD) and Labnet for Targeted VPDs in the Western Pacific Region

Immunization is a highly cost effective public health intervention that has achieved dramatic reductions in disease, disability and death. By the end of 2010, the Western Pacific Region remained polio-free for over 13 years, regional measles incidence decreased to 30 cases per million population, over 87% of the Region’s population lived in countries and areas with <2% prevalence of chronic hepatitis infection among children, and 31 countries and areas have eliminated maternal and neonatal tetanus (MNT) as a public health problem. Demand is increasing for new and underutilized vaccines that prevent major causes of diarrhoea, pneumonia, meningitis, and encephalitis, as well as cervical cancer, and with it an increased need to assure vaccine safety, quality and adequate supply chain management. Programme monitoring and high quality surveillance supported by an accredited laboratory network are increasingly needed to demonstrate progress or achievement of disease eradication, elimination and control initiatives, and systematic expansion of surveillance for diseases targeted by new or underutilized vaccines is needed to guide decision making and monitor impact. Since the Western Pacific Region established the twin goals of measles elimination and hepatitis B control by 2012 in 2005, the region has made good progress towards measles elimination and hepatitis B control. Despite measles outbreaks in number of countries (Vietnam and Philippines, the overall number of reported measles cases has been dramatically decreased by 2011. Most countries in this region conducted measles supplementary immunization activities (SIA) or catch-up campaigns. China performed a historic measles SIA in 2010 vaccinating more than 100 million population. Vietnam, Cambodia and Philippines also conducted measles campaigns in 2010-2011 to provide an opportunity for second dose measles vaccine. The measles laboratory network consisting of 382 laboratories has played a crucial role by providing timely and reliable laboratory confirmation and virus identification, while maintaining high standards of quality. Genotype and sequence data on circulating measles virus strains are critical to track virus transmission and verify measles elimination in each country. The Western Pacific Region celebrated the 10th anniversary of its certification as a polio-free region in October 2010. However, as many of you know, on 26 August, China’s Ministry of Health reported four laboratory-verified cases of wild polio virus in the Xinjiang Uygur Autonomous Region. Since then 18 wild polio cases were reported in Xinjiang province in China and as of 20 October 2011, 47 wild poliovirus strains were detected from 18 AFP, 16 contacts and 12 healthy people in China. Sequence comparison indicated 99% homology with type 1 wild poliovirus strains isolated from Pakistan in 2010 implicating the virus was imported from Pakistan. The WHO polio laboratory network including China CDC and US CDC was able to identity the source of virus within just a few hours to provide critical information to the national EPI programme. An emergency response involving oral poliovirus vaccine immunization has been initiated, and two rounds of OPV vaccination were conducted in September and October in Xinjiang province in China and third round using monovalent OPV is planned in November. This event highlights the important role of the laboratory networks and how quickly they can provide critical information to the national programmes and WHO. Inequities in routine immunization coverage were addressed through WHO-supported training on district level immunization strengthening and development of national multi-year immunization plans that included special efforts to vaccinate hard to reach children. WHO also organized a Regional Vaccination Week for the Western Pacific involving more than 30 countries and areas. The first Regional Vaccination Week last April 2011 celebrated the achievements of immunization programmes in promoting healthy communities throughout our Region. With the achievements made to date we have established the foundation for sustained change to improve the efficiency, equity, and effectiveness of immunization – and ultimately of health systems. However, to move into the next decade, we need to understand what our remaining challenges are. We have to do our analysis in an evidence-based way and work with Member States in a realistic and consensus-building fashion. Strengthening immunization systems remains at the core of EPI disease control efforts. Despite the many successes of EPI, disparities in immunization coverage remain between and within countries, threatening achievement of the Regional goals of measles elimination and hepatitis B control, placing at risk the Region’s polio free status and achievement of MNT elimination, and limiting the impact of new and underutilized vaccine introduction. To fully realize the benefits of immunization and help achieve Millennium Development Goals, the Regional Office EPI Unit has developed a strategic framework in line with the Global Immunization Vision and Strategy and that has five objectives: 1) ensure equitable access to vaccines of assured quality, including pandemic vaccines; 2) achieve targeted disease eradication, elimination or control; 3) promote the rational introduction of new vaccines; 4) .strengthen vaccine preventable disease (VPD) monitoring and surveillance systems, laboratory capacity, and data use; and 5) strengthen communication, partnerships and advocacy to support immunizations and promote integration of immunization with other health interventions. WHO support for programme monitoring and VPD surveillance included supportive assistance and corrective feedback on the WHO-UNICEF Joint EPI Reporting Form; development and training on data management tools for traditional and new vaccine surveillance; development of models for monitoring/assessing low performance (at national and subnational level) and epidemiological risk for diseases like Polio and Measles; and continuous supportive and corrective feedback on surveillance data quality. The WHO EPI Unit collaborated with other Regional Office divisions and units to improve various aspects of VPD surveillance. VPD surveillance sensitivity was enhanced by integrating VPD surveillance with event based surveillance training in collaboration with the Disease Surveillance and Response Unit. Laboratory networks for poliomyelitis, measles and rubella, and Japanese encephalitis continued to provide timely and reliable laboratory confirmation and virus identification. All poliomyelitis network laboratories and almost all measles and rubella network laboratories in the Region are fully accredited. The polio laboratory network introduced a new algorithm/protocol that will shorten the interval between specimen collection and virus isolation. Real time polymerase chain reaction (PCR) for the intratypic differentiation and the screening of vaccine derived polioviruses was successfully implemented by the laboratory network during 2010. Measles and AFP surveillance and laboratory performances are being strengthened through a series of training, feedback mechanisms and supplemental surveillance actitivities (e.g., environmental and enterovirus surveillance for poliovirus). The WHO measles regional reference laboratory (RRL) in Hong Kong provided genotyping results for countries including Cambodia, Lao People’s Democratic Republic, Malaysia, Mongolia, Philippines and Vietnam. Regional capacity to conduct measles genotyping was enhanced after conducting two hands on laboratory training for measles network laboratories in 2009 and 2010. A newly established Japanese encephalitis laboratory network began to provide laboratory confirmation and implement quality assurance measures, such as proficiency testing and confirmatory testing. The two hands-on training workshops were held in 2009 and 2010 to further improve laboratory performance and the quality of testing.