Evaluating the effect of measles and rubella mass vaccination campaigns on seroprevalence in India: a before-and-after cross-sectional household serosurvey in four districts, 2018–2020

Added value of the measles-rubella supplementary immunization activity in reaching unvaccinated and under-vaccinated children, a cross-sectional study in five Indian districts, 2018–20

“…We anticipate the added value of the SIA on coverage may have been higher among the older children who would not have benefitted from intensified routine immunization activities in recent years and may therefore have been captured with a first or second dose through the SIA. This was also observed in our seroprevalence analyses where a gap in measles seropositivity prior to the SIA was filled following the SIA [15] . Depending on measles transmission in any given area, however, unvaccinated children may acquire measles before an SIA and reduce the added value from the SIA.…”

“…In the context of rubella vaccine introduction, most children received value from the supplementary dose, even if they had already received two doses of measles vaccine, as it provided the first opportunity for a rubella-containing vaccine [7] . The added value of the SIA in terms of rubella protection was also observed in our seroprevalence analysis [15] .…”

“…Three of the thirty selected clusters in Dibrugarh, Assam could not be completed due to the COVID-19 pandemic. Sample size was estimated for the overall serosurvey conducted in these districts, assuming rubella seroprevalence of 50 % among both the younger and older age groups, with an absolute precision of 10 %, a design effect of 2, and a 95 % confidence level [15] .…”

“…How well SIAs reach children missed by the routine immunization program is a key metric in assessing their added value. In this paper, we are defining “added value” as receipt of the first or second dose of MCV through the SIA, while recognizing that this is an incomplete proxy for overall added value in the absence of information on natural immunity [15] . Measuring these indicators of reaching under-vaccinated children as part of post-SIA surveys has recently been emphasized, such as the proportion of children receiving the supplementary dose stratified by the number of routine doses received prior to the SIA [12] , [16] .…”