Epidemic of measles following the nationwide mass immunization campaign

Abstract

BackgroundA prolonged measles epidemic occurred in Wenzhou City, China after a nationwide measles mass immunization campaign (MMIC) in 2010. We conducted an investigation to identify factors contributing to this epidemic and to provide evidence-based recommendations for measles elimination strategies in China.MethodsMeasles was diagnosed using the national standard case-definitions. We estimated the population vaccination coverage based on the proportion of measles patients that had been vaccinated. In a case–control investigation, all measles patients who received treatment in The Second Affiliated Hospital of Wenzhou Medical College (Hospital S) during November 1 to December 31, 2010 served as cases; controls were randomly selected among all other patients who received treatment in Hospital S during the same time period, frequency matched by month of hospital visit. We reviewed medical records of case- and control-patients to compare their exposure history at Hospital S and to its intravenous rehydration room (IV room) during the incubation period (7–21 days before their illness onset).ResultsThe attack rate of measles in Wenzhou City was 3.3/100,000 during September 1, 2010 to January 11, 2011. Children aged 8-11 m had the highest attack rate (171/100,000) of all age groups. In children not age-eligible for the MMIC but should have been routinely vaccinated after the MMIC, the vaccination rate was only 52%. In the case–control investigation, 60% (25/42) of case-patients compared with 21% (35/168) of control-patients had visited Hospital S (adjusted ORM-H = 5.5, 95% CI = 2.7–11). Among unvaccinated children who had received treatment in Hospital S, 84% (21/25) of case-patients compared 38% (11/29) of control-patients had visited the IV room (adjusted ORM-H = 9.2, 95% CI = 1.5–59).ConclusionRelaxed routine measles vaccination among children after the MMIC was the main factor responsible for this epidemic. Exposure in the IV room at Hospital S facilitated the epidemic. To reach the goal of measles elimination, the Chinese public health authorities should make greater efforts to improve timely routine measles vaccination, and to reduce nosocomial transmission.

Monitoring progress towards the elimination of measles in China: an analysis of measles surveillance data

“…Additional studies are needed to identify why, in the routine programme, not all of the 25 and could well be beneficial in China. 26 Records-based surveys of vaccine coverage may also help to identify any gaps in population immunity and the main risk factors for failure to be vaccinated. 27 In China, huge numbers of individuals are currently migrating from rural areas to towns and cities, largely in search of employment.…”

Timeliness and completeness of measles vaccination among children in rural areas of Guangxi, China: A stratified three-stage cluster survey

“…Thus, the goal of measles elimination was not met in WHO Europe Region (WHO/EUR) by 2010 9 . Similarly, outbreaks of measles frequently occur in WHO Western Pacific Region (WHO/WPR), a region with high measles vaccination coverage 10, 11, 12, 13…”

Kızamık bulaşında bir risk faktörü olarak hastane maruziyeti: Vaka-kontrol çalışması, Türkiye

“…24 Field investigations in other countries where reliable cold-chain is available also showed high effectiveness of MCV. 19,23,25,26 The fact that measles outbreaks can still occur even though the vaccine is effective and vaccination coverage is high again underscores the importance of addressing other risk factors (such as nosocomial transmission) for measles elimination.…”