Increased measles and rubella seroprevalence in children using residual blood samples from health facilities and household serosurveys after supplementary immunization activities in two districts in India

Abstract

Residual blood specimens provide a sample repository that could be analyzed to estimate and track changes in seroprevalence with fewer resources than household-based surveys. We conducted parallel facility and community-based cross-sectional serological surveys in two districts in India, Kanpur Nagar District, Uttar Pradesh, and Palghar District, Maharashtra, before and after a measles-rubella supplemental immunization activity (MR-SIA) from 2018 to 2019. Anonymized residual specimens from children 9 months to younger than 15 years of age were collected from public and private diagnostic laboratories and public hospitals and tested for IgG antibodies to measles and rubella viruses. Significant increases in seroprevalence were observed following the MR SIA using the facility-based specimens. Younger children whose specimens were tested at a public facility in Kanpur Nagar District had significantly lower rubella seroprevalence prior to the SIA compared to those attending a private hospital, but this difference was not observed following the SIA. Similar increases in rubella seroprevalence were observed in facility-based and community-based serosurveys following the MR SIA, but trends in measles seroprevalence were inconsistent between the two specimen sources. Despite challenges with representativeness and limited metadata, residual specimens can be useful in estimating seroprevalence and assessing trends through facility-based sentinel surveillance.

Keywords: measles (rubeola); rubella; serology; vaccines.

Figure 1.

Location of facilities where residual specimens were collected and survey clusters for community-based serosurvey. (a) Kanpur Nagar District, Uttar Pradesh. (b) Palghar District, Maharashtra. Legend: Grayscale corresponds to the population size of each enumeration area based on the 2011 census estimates. Red circles indicate community-based survey clusters. Blue circles indicate the originating facilities for specimens received at Paliwal Diagnostics (Kanpur Nagar District) or Hind Laboratory (Palghar District). Black squares indicate fixed point residual specimen collection at G.S.V.M. Medical College (Kanpur Nagar District) or the subdistrict hospitals in Dahanu and Kasa (Palghar District). Right side maps indicate the state (blue) and district (orange) locations within the country.

Figure 2.

Measles and rubella seroprevalence before and after the measles-rubella supplemental immunization activity among children 9 months to <15 years seen at health facilities, by district.

Figure 3.

Measles and rubella seroprevalence before and after the measles-rubella supplemental immunization activity among children 9 months to <15 years seen at health facilities in Kanpur Nagar District Uttar Pradesh, by public and private facility type. Legend: Facilities include GSVM Medical College (public hospital) and Paliwal Diagnostics (private diagnostic laboratory). Numbers at bottom of each bar represent the sample size in each facility and period.

Figure 4.

Measles and rubella seroprevalence before and after the measles-rubella supplemental immunization activity among children 9 months to <15 years, by specimen source. Legend: In Palghar District, Maharashtra, all analyses are restricted to children 1 year and older due to lack of facility specimens for children 9 months – 1 year. For community analyses, age is age at time of survey and estimates are survey weighted. Facility samples age-standardized to pre-SIA community age distribution.

Figure 5.

Seroprevalence by sampling cluster from community-based serosurvey in Kanpur Nagar District, Uttar Pradesh and Palghar District, Maharashtra.