Risk factors for measles in children aged 8 months–14 years in China after nationwide measles campaign: A multi-site case-control study, 2012–2013

Abstract

Introduction:Endemic measles persists in China, despite >95% reported coverage of two measles-containing vaccine doses and nationwide campaign that vaccinated more than 100 million children in 2010. In 2011, almost half of the 9943 measles cases in China occurred in children eligible for measles vaccination. We conducted a case-control study during 2012–2013 to identify risk factors for measles infection in children aged 8 months–14 years.Methods:Children with laboratory-confirmed measles were age- and neighborhood-matched with three controls. We interviewed parents of case and control infants on potential risk factors for measles. We calculated adjusted matched odds ratios and 95% confidence intervals of risk factors. We calculated attributable fractions for risk factors that could be interpreted as causal and vaccine efficacy (VE) for the measles containing vaccine (MCV) used in the Chinese immunization program.Results:In all, 969 case-patients and 2845 controls were enrolled. In multivariable analysis, lack of measles vaccination both overall (mOR 22.7 [16.6, 31.1] and when stratified by region (east region, mOR 74.2 [27.3, 202]; central/western regions mOR 17.4 [12.5, 24.3]), hospital exposure (mOR 63.0, 95% CI [32.8, 121]), and migration among counties (overall mOR 3.0 [2.3, 3.9]) were significant risk factors. The calculated VE was 91.9–96.1% for a single dose of MCV and 96.6–99.5% for 2 doses.Conclusions:Lack of vaccination was the leading risk factor for measles infection, especially in children born since the 2010 supplementary immunization activity. Reducing missed vaccination opportunities, improving immunization access for migrant children, and strengthening school/kindergarten vaccine checks are needed to strengthen the routine immunization program and maintain progress toward measles elimination in China.

Measles outbreak investigation in Ginnir district of Bale zone, Oromia region, Southeast Ethiopia, May 2019

“…This is in line with the finding of case control study conducted in Kabridehar town and Kabridehar district of Somali Regional State, Ethiopia, indicating that being vaccinated against measle vaccine is protective factor for contracting measle [ 15 ), 16 ]. Similarly, our finding is consistent with the case control study conducted in Uganda and China indicating unvaccinated against measles was responsible for most measles infection in children [ 18 ), 19 ]. This is due to the fact that vaccination against measles is vital for prevention of measles infection [ 1 - 3 ].…”

“…Measles outbreaks occur when the accumulated number of susceptible individuals is greater than the critical number of susceptible individuals, or epidemic threshold for a given population [ 3 ]. Various literature on outbreak investigation showed that the possible factors for measles infections were being unvaccinated for measles, low immunization coverage, malnutrition, poor cold chain management and travel history to measle area, presence of measles case in neighbor or in the household and having contact with person with measles case [ 15 - 18 ]. Despite the increase in immunization coverage (administrative) of measles in the country, there was a widespread measles outbreak reported from different zones of Oromia region including Bale zone in 2019.…”

Were infections in migrants associated with the resurgence of measles epidemic during 2013–2014 in southern China? A retrospective data analysis

“…One of the major findings of this study is that substantial increases in the proportions of infections were identified among both locals and migrants with no known immunization history of measles during 2009-2012 and 2013-2014. This is in accordance with the consensus that a lack of vaccination is the most significant risk factor for measles infection (World Health Organization, 2018; Centres for Disease Control and Protection (US), 2018a; Hao et al, 2016). In fact, the Guangzhou CDC has pointed out that there was a decrease in vaccine uptake among citizens, partially due to the negative reports and quackery about vaccines (Guangzhou Center for Disease Control and Prevention, 2014).…”

Progress Toward Measles Elimination — China, January 2013–June 2019

“…MCVs used in China were found to be highly immunogenic in infants aged 8 months, and coadministration of Japanese encephalitis vaccine did not reduce measles seroconversion rates ( 6 ). In a Chinese study of risk factors for measles in children aged 8 months–14 years after a nationwide SIA, the estimated measles vaccine effectiveness among children was >95%, and being unvaccinated was the leading risk factor for infection ( 7 ). In addition, hospitals were important sites of measles virus transmission, and internal migration was associated with risk for measles acquisition ( 7 ).…”