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.

Epidemiology of a measles epidemic in Vietnam 2008-2010.

BACKGROUND: Vietnam conducted a measles catch-up supplementary immunization activity (SIA) during 2002-2003 that targeted children 9 months-10 years of age, followed by subnational SIAs targeting persons up to 20 years of age during 2004 and 2007-2008. A measles epidemic began among young adults in October 2008 in the northern region, spread nationwide during early 2009, and continued during 2010. METHODS: We reviewed national epidemiologic and laboratory surveillance data. Measles cases were defined and classified according to World Health Organization recommendations. RESULTS: From October 2008 through January 2010, 7948 confirmed measles cases were reported from 60 of 63 provinces, an incidence of 93 cases per million population. Incidence was 328 cases per million population among children age 1-4 years, 318 cases per million population among infants, and 271 cases per million population among persons aged 20-24 years. Few cases were reported among persons 7-17 or >27 years of age. Median age of cases trended downward over time in all regions. CONCLUSIONS: The 2002-2003 measles SIA protected its targeted age group, but this epidemic was not prevented by follow-up subnational SIAs in selected provinces during 2007-2008. Transmission began among young adults and was sustained among children. The outcome of Vietnam's 2010 SIA targeting children only and change in routine schedule may influence elimination strategies for other countries.

Outbreak of measles in the Republic of Korea, 2007: importance of nosocomial transmission.

BACKGROUND: From 2002 through 2006, Republic of Korea conducted extensive measles elimination activities and declared elimination in 2006. An outbreak of measles involving 180 confirmed cases occurred during 2007. METHODS: An outbreak investigation was performed and enhanced surveillance was implemented. Detailed case investigations and laboratory testing included serologic and molecular diagnostic methods. Cases were classified according to World Health Organization and national guidelines. RESULTS: During 2007, 451 suspected cases were reported and 180 (40%) cases were confirmed as measles during epidemiologic weeks 14-42. Incidence during the outbreak was 3.7 cases per million persons, excluding imported cases. Most confirmed cases were reported from Seoul; 137 (76%) cases were among children <24 months old, 124 (69%) case patients had no history of measles vaccination, and 81 (45%) case patients resulted from nosocomial transmission in 6 hospitals. Community members, patients, and health care workers all contributed to measles virus transmission. Limited outbreak control measures were implemented; high population immunity likely accounted for the self-limited transmission during this outbreak. CONCLUSIONS: Limited outbreaks of measles, in which nosocomial transmission can play an important role, may occur after countries have declared elimination. Timely and opportunistic vaccination may help prevent such outbreaks; high-quality surveillance is critical for their detection.