Measles clinical presentation, hospitalization and vaccination status among children in a community-wide outbreak.

Abstract

In 2018-2019, a measles outbreak emerged in Israel (4158 notified cases). We aimed to evaluate the measles characteristics and the vaccination status among children during the outbreak. We performed a cross-sectional study of measles cases in children under 18years, residing in the Jerusalem district (2254 notified measles cases, June 2018-May 2019). The variables included: clinical symptoms (fever, rash, cough, coryza, conjunctivitis), hospitalizations and child's vaccination status. The national measles vaccination schedule includes two vaccine doses (at ages 12months and 6years). Children, under 18years, comprised 79% (1782/2254) of the notified measles cases. The hospitalization rate was 6.6%. There was one fatality. The measles vaccination status was analyzed by age groups. Infants under 12months (n=425) were excluded. Children aged 1-5years (n=785) and 6-17years (n=572) were expected to receive 1 and 2 measles vaccine doses, respectively. Most (88%) children (1-17years) were unvaccinated, 138 received 1 measles vaccine dose and 24 received 2 doses. Of children aged 1-5years 106 (13.5%) received 1 vaccine dose and were compared to unvaccinated children. Vaccinated children showed lower rates of clinical symptoms and lower risk for hospitalization compared to unvaccinated children (Odds ratio: OR=4.8, 95%CI 1.12-20.2). Vaccine effectiveness of 79% was estimated for one measles vaccine dose against hospitalization. Data on vaccine effectiveness reflect how well vaccines protect children against infection and morbidity. We evaluated the real-world effectiveness of measles vaccine, in an outbreak setting, and showed reduced morbidity in once-vaccinated children.