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HOME > Osong Public Health Res Perspect > Volume 2(Suppl 1); 2011 > Article
WHO’s Initiatives to Control Vaccine Preventable Diseases (VPD) and Labnet for Targeted VPDs in the Western Pacific Region
Youngmee Jee
Osong Public Health and Research Perspectives 2011;2(Suppl 1):S3-S3.
Published online: December 31, 2011

Expanded Programme on Immunization, Division of Combating Communicable Diseases, WHO Western Pacific Regional Office, Manila, Philippines.

Copyright ©2012, Korea Centers for Disease Control and Prevention

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License () which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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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.
WHO will continue to work with national counterparts to build sustainable capacity at country level to improve immunization performance, describe and respond to epidemiological risk of vaccine preventable diseases, and enhance synergies between immunization and other health programmes. WHO will support routine immunization system strengthening and assist members states in achieving global and regional disease eradication, elimination and control goals as well as Millennium Development Goals and goals contained within the Global Immunization Vision and Strategy. External certification and verification commissions and expert resource panels will be used increasingly to not only monitor and validate progress towards global and regional immunization goals, but to provide added technical support for member states. Introduction of pneumococcal and rotavirus vaccines and the prevention of measles infection will help decrease the burden of pneumonia and diarrhoea, moving the Region towards success in implementing its Regional Child Survival Strategy.
To eliminate measles regionally by 2012 and reduce the threat of importation and subsequent spread, countries and areas will need to identify and respond to any residual chains of measles virus transmission. This will require 1) an implementable action plan to interrupt measles virus transmission in remaining groups at risk, and 2) improvement of surveillance performance to ensure timely laboratory or epidemiologic confirmation of cases, measles virus identification, periodic epidemiologic analysis, and ultimately, verification of measles elimination. High level political commitment will be critical to ensure the human and financial resources necessary to achieve the goal. Measles elimination activities may simultaneously address rubella control whenever possible, and countries and areas that have not yet introduced rubella containing vaccine should consider doing so in line with the recent WHO position paper.
Achieving regional Hepatitis B control will require increasing coverage with 3 timely doses of Hepatitis B vaccine (HepB), including a dose within 24 hours of birth, in the 9 countries that will not achieve the 2012 milestone. The need to increase timely HepB birth dose coverage offers an opportunity to simultaneously strengthen neonatal and maternal health care. Countries and areas that have achieved adequate HepB coverage during the past 5 years should conduct serologic surveys to measure impact and initiate the regional process of verifying reduced chronic infection rates among children.
All countries and areas must remain vigilant to identify and respond to the threat of poliovirus importations. Poliomyelitis risk assessments should be regularly conducted at the sub-national level, and actions should be taken to ensure adequate levels of population immunity and surveillance performance. VPD laboratory networks continue to be strengthened by laboratory hands on training workshops and regularly assessed by on-site review to maintain accreditation status.
Joint resource mobilization initiatives have been undertaken for all targeted vaccine preventable disease initiatives. WHO will continue to provide technical support and seek additional financial support on behalf of member states for these and other EPI needs.

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