Risk Factors for Measles Outbreak in Pune City: A Case-Control Study.

Introduction: The first case of measles outbreak in Pune was reported on November 14, 2022; since then, there were a total of 266 cases from Pune Municipal Corporation (PMC).

Objective: The objective is to find out risk factors associated with measles during an outbreak in Pune city.

Methods: This was a 1:1 unmatched case-control study conducted from February 2023 to September 2023 in PMC. Cases were immunoglobulin M-positive laboratory-confirmed measles cases and a control was any child who did not have any rash in the study period and not living in the same household with a case. Face-to-face interview of cases and controls were carried out by visiting houses to obtain information on sociodemographic characteristics and immunization history, including Vitamin A supplementation. The sample size was 200.

Results: There was a statistically significant difference among the mean age of cases (53.18 ± 18.08) and controls (30.08 ± 18.08). Father's and mother's education, immunization, and Vitamin A supplementation were also significant. Those who had not received any dose of measles-rubella (MR) vaccine had a higher chance of having infection with an odds ratio of 3.093 (95% confidence interval [CI]: 2.37-4.037) and those who were partially immunized with 1 dose of MR showed odds ratio of 2.027 (95% CI: 1.328-3.096) for having measles infection. COVID-19 lockdown was the reason given by majority (29.3%) for unimmunized of the measles vaccine.

Conclusions: In this study, the main cause of this measles outbreak was under immunization. It is important to maintain high levels of under 5 immunization even during emergencies to prevent future measles outbreaks.