An Outbreak of Measles among adolescents in a Health Care Setting, Bangalore, Karnataka, India

Abstract

Background: Despite high immunization coverage, outbreaks of measles do occur, but occurrenceof measles outbreak among adolescents in a health care institution setting in India, is rather unusualor unreported. Methods: On the 21st November 2013, cases of suspected measles among the studentswere reported at St. John’s Medical College, Bangalore. The preliminary investigation using theepidemiological case sheet identified seven suspected cases of measles. This led to a detailedinvestigation for a suspected outbreak at the campus. The outbreak was notified to the governmentauthority. A measles outbreak investigation case sheet was distributed among the students and a doorto door survey was carried out. The laboratory confirmation of suspected measles cases was done atthe National Institute of Virology, Bangalore by IgM test for measles specific antibodies, viral cultureand RT PCR. Results: The outbreak occurred during the months of November and December 2013.A total of 13 confirmed cases of measles were identified with an overall attack rate of 2%. Five caseswere confirmed by IgM test for measles antibodies, besides virus isolation and RT PCR was positivefor two cases. More than half (54%) of the suspected cases were vaccinated for measles and the restwere unvaccinated (23%) or had an unknown vaccination status (23%). There were no complications ordeaths due to measles. Conclusion: An outbreak of measles among a group of adolescents in a healthcare institutional setting who were mostly vaccinated raises a concern about the vaccine effectivenessand the duration of vaccine efficacy after immunization. Along with improving the immunizationcoverage of two doses of measles vaccine, research is needed to determine the most-effective timing ofdelivering the second routine dose to bring down the susceptible population.