Progress and challenges for measles elimination by 2012 in the Western Pacific Region.

BACKGROUND: The 37 countries and areas of the World Health Organization (WHO) Western Pacific Region have targeted measles for elimination by 2012. METHODS: We reviewed routine and supplementary immunization coverage based on 2010 WHO/United Nation's Children's Fund (UNICEF) estimates and Joint Reporting Forms and epidemiologic and laboratory data submitted by the countries and areas. RESULTS: In 2009, 21 of 37 countries and areas had ≥90% coverage with a first dose of measles vaccine; 32 countries and areas provided 2 routine doses of measles vaccine with 94% weighted average coverage among those reporting. From 1996 to 2009, 235 million persons received measles vaccine during 94 immunization campaigns in 30 countries and areas. As of 2009, 2.8 suspected cases per 100,000 population were discarded as nonmeasles; however, only 43% of second level administrative units reported at least 1 discarded case per 100,000. Adequate specimen collection rate was 71%. Measles incidence was 34 per million population in 2009, a 58% decrease compared with 2008 and the lowest ever reported. As many as 25 countries and areas already may have eliminated measles. CONCLUSIONS: Achieving the 2012 measles elimination goal is feasible provided political and financial commitments are increased at every level to further improve routine and supplementary immunization activity (SIA) coverage and surveillance in every district.

Emergence of vaccine-derived poliovirus type 2 after using monovalent type 2 oral poliovirus vaccine in an outbreak response, Philippines.

Objective: In response to an outbreak of circulating vaccine-derived poliovirus (cVDPV) type 2 in the Philippines in 2019-2020, several rounds of supplementary immunization activities using the monovalent type 2 oral poliovirus vaccine (OPV) were conducted for the first time in the Western Pacific Region. After use of the monovalent vaccine, the emergence of vaccine-derived poliovirus unrelated to the outbreak virus was detected in healthy children and environmental samples. This report describes the detection of this poliovirus in the Philippines after use of the monovalent type 2 OPV for outbreak response. Methods: We describe the emergence of vaccine-derived poliovirus unrelated to the outbreak detected after supplementary immunization activities using the monovalent type 2 OPV. This analysis included virus characterization, phylogenetic analyses and epidemiological investigations. Results: Three environmental samples and samples from six healthy children tested positive for the emergent vaccine-derived poliovirus. All isolates differed from the Sabin type 2 reference strain by 6-13 nucleotide changes, and all were detected in the National Capital Region and Region 4, which had conducted supplementary immunization activities. Discussion: Since the 2016 removal of type 2 strains from the OPV, vaccine-derived poliovirus outbreaks have occurred in communities that are immunologically naive to poliovirus type 2 and in areas with recent use of monovalent OPV. To prevent the emergence and further spread of cVDPV type 2, several interventions could be implemented including optimizing outbreak responses by using the monovalent type 2 OPV, accelerating the availability of the novel type 2 OPV, strengthening routine immunization using inactivated polio vaccine and eventually replacing OPV with inactivated poliovirus vaccine for routine immunization.

Hepatitis B control in the World Health Organization's Western Pacific Region: targets, strategies, status.

WHO's Western Pacific Region has the highest rates of hepatitis B virus (HBV) infection in the world; most countries have >8% prevalence of HBV chronic infection in their adult population. In 2005, Member States of the Region adopted a resolution to reduce chronic hepatitis B infection prevalence to less than 2% among children by 2012 as an interim milestone toward a regional goal of less than 1% prevalence. Country commitments to hepatitis B control and successes represent a remarkable public health achievement by preventing over 1 million chronic infections and 300,000 HBV-related deaths per birth cohort. Reported here is a review of the process and strategies for translating this public health initiative into practice including such activities as setting up an Expert Resource Panel, developing implementation guidelines, focusing on facility births while supporting efforts to reach home births, providing guidance for conducting seroprevalence surveys, and establishing a verification process.