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Measles vaccine coverage estimates in an outbreak three years after the nation-wide campaign in China: implications for measles elimination, 2013.

Ma C, Li F, Zheng X, Zhang H, Duan M, Yang Y, Hao L, Su Q, Rodewald L, Guo B, Xiao S, Wang H, Li L, Li J, Luo H, Gao L - BMC Infect. Dis. (2015)

Bottom Line: We measured MCV coverage using 5 different methods during an investigation on this outbreak and compared our estimates with reported rates.Our estimated MCV coverage rates were: (1) administrative method: 84.1%-87.0% for MCV1 and 80.3%-90.0% for MCV2, (2) in-house survey: 83.3% of 9-17 month children received MCV1, and 74.5% of 24-47 month children received MCV2, (3) clinic record review: 85.5% of 9-17 month children received MCV1, and 73.2% of 24-59 month children received MCV2, (4) field VE method: 83.6% of 9-47 month children received one or more MCV doses, and (5) serology: seropositive rates were <80% in the 12-17 and 18-23 month age cohorts.Compared with reported coverage >95%, our 5 coverage assessments all showed substantially lower coverage.

View Article: PubMed Central - PubMed

Affiliation: National Immunization Programme, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Xicheng District, Beijing, China. maachao@163.com.

ABSTRACT

Background: China is approaching measles elimination, but indigenous measles still circulates. County L in China has reported measles-containing vaccine (MCV) coverage rates >95% since 2000. Despite high reported coverage, a large measles outbreak occurred among young children in L County. We measured MCV coverage using 5 different methods during an investigation on this outbreak and compared our estimates with reported rates.

Methods: Reported coverage rates are determined by aggregating clinic-based data across the county: doses administered in each clinic divided by the number of children registered in each clinic. Our methods estimated coverage for the 2010-2012 birth cohort, and were (1) administrative method: doses administered in clinics divided by the birth cohort recorded in the Statistical Year Book, (2) house-to-house convenience-sample survey of children living near cases, (3) vaccination clinic records review, (4) determination of a convenience sample of measles outbreak cases' vaccination statuses and using the field vaccine efficacy outbreak equation to estimate population coverage, and (5) a seroprevalence survey using a convenience sample of residual blood samples from hospitals.

Results: The measles outbreak totaled 215 cases, representing an incidence of 195.8 per million population. Our estimated MCV coverage rates were: (1) administrative method: 84.1%-87.0% for MCV1 and 80.3%-90.0% for MCV2, (2) in-house survey: 83.3% of 9-17 month children received MCV1, and 74.5% of 24-47 month children received MCV2, (3) clinic record review: 85.5% of 9-17 month children received MCV1, and 73.2% of 24-59 month children received MCV2, (4) field VE method: 83.6% of 9-47 month children received one or more MCV doses, and (5) serology: seropositive rates were <80% in the 12-17 and 18-23 month age cohorts.

Conclusions: Compared with reported coverage >95%, our 5 coverage assessments all showed substantially lower coverage. China should evaluate guidelines for reporting vaccination coverage and identify feasible improvements to the assessment methods.

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Weekly distribution of reported measles cases, 2008-November 2013, L County, Hu Nan province, China.
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Fig1: Weekly distribution of reported measles cases, 2008-November 2013, L County, Hu Nan province, China.

Mentions: A total of 215 measles cases were identified in 24 of 26 townships in L County; 209 were laboratory confirmed and 6 were epidemiologically linked to a laboratory confirmed case. Of these, 153 cases (71.2%) were male, representing incidence (per million population) of 243.9 for male and 107.1 for female in this county. The outbreak started on January 9 and ended on June 19, 2013 (Figure 1). Of the 215 cases, 189 cases (87.9%) were born after 1 January 2010 and therefore had not been part of the 2010 nationwide measles campaign; 16 cases (7.4%) were born between 1 October 2005 and 31 December 2009 and were part of the 2010 nationwide campaign target age group; and 10 cases (4.6%) were >15 years old (Figure 2).Figure 1


Measles vaccine coverage estimates in an outbreak three years after the nation-wide campaign in China: implications for measles elimination, 2013.

Ma C, Li F, Zheng X, Zhang H, Duan M, Yang Y, Hao L, Su Q, Rodewald L, Guo B, Xiao S, Wang H, Li L, Li J, Luo H, Gao L - BMC Infect. Dis. (2015)

Weekly distribution of reported measles cases, 2008-November 2013, L County, Hu Nan province, China.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4307911&req=5

Fig1: Weekly distribution of reported measles cases, 2008-November 2013, L County, Hu Nan province, China.
Mentions: A total of 215 measles cases were identified in 24 of 26 townships in L County; 209 were laboratory confirmed and 6 were epidemiologically linked to a laboratory confirmed case. Of these, 153 cases (71.2%) were male, representing incidence (per million population) of 243.9 for male and 107.1 for female in this county. The outbreak started on January 9 and ended on June 19, 2013 (Figure 1). Of the 215 cases, 189 cases (87.9%) were born after 1 January 2010 and therefore had not been part of the 2010 nationwide measles campaign; 16 cases (7.4%) were born between 1 October 2005 and 31 December 2009 and were part of the 2010 nationwide campaign target age group; and 10 cases (4.6%) were >15 years old (Figure 2).Figure 1

Bottom Line: We measured MCV coverage using 5 different methods during an investigation on this outbreak and compared our estimates with reported rates.Our estimated MCV coverage rates were: (1) administrative method: 84.1%-87.0% for MCV1 and 80.3%-90.0% for MCV2, (2) in-house survey: 83.3% of 9-17 month children received MCV1, and 74.5% of 24-47 month children received MCV2, (3) clinic record review: 85.5% of 9-17 month children received MCV1, and 73.2% of 24-59 month children received MCV2, (4) field VE method: 83.6% of 9-47 month children received one or more MCV doses, and (5) serology: seropositive rates were <80% in the 12-17 and 18-23 month age cohorts.Compared with reported coverage >95%, our 5 coverage assessments all showed substantially lower coverage.

View Article: PubMed Central - PubMed

Affiliation: National Immunization Programme, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Xicheng District, Beijing, China. maachao@163.com.

ABSTRACT

Background: China is approaching measles elimination, but indigenous measles still circulates. County L in China has reported measles-containing vaccine (MCV) coverage rates >95% since 2000. Despite high reported coverage, a large measles outbreak occurred among young children in L County. We measured MCV coverage using 5 different methods during an investigation on this outbreak and compared our estimates with reported rates.

Methods: Reported coverage rates are determined by aggregating clinic-based data across the county: doses administered in each clinic divided by the number of children registered in each clinic. Our methods estimated coverage for the 2010-2012 birth cohort, and were (1) administrative method: doses administered in clinics divided by the birth cohort recorded in the Statistical Year Book, (2) house-to-house convenience-sample survey of children living near cases, (3) vaccination clinic records review, (4) determination of a convenience sample of measles outbreak cases' vaccination statuses and using the field vaccine efficacy outbreak equation to estimate population coverage, and (5) a seroprevalence survey using a convenience sample of residual blood samples from hospitals.

Results: The measles outbreak totaled 215 cases, representing an incidence of 195.8 per million population. Our estimated MCV coverage rates were: (1) administrative method: 84.1%-87.0% for MCV1 and 80.3%-90.0% for MCV2, (2) in-house survey: 83.3% of 9-17 month children received MCV1, and 74.5% of 24-47 month children received MCV2, (3) clinic record review: 85.5% of 9-17 month children received MCV1, and 73.2% of 24-59 month children received MCV2, (4) field VE method: 83.6% of 9-47 month children received one or more MCV doses, and (5) serology: seropositive rates were <80% in the 12-17 and 18-23 month age cohorts.

Conclusions: Compared with reported coverage >95%, our 5 coverage assessments all showed substantially lower coverage. China should evaluate guidelines for reporting vaccination coverage and identify feasible improvements to the assessment methods.

Show MeSH
Related in: MedlinePlus