A Mixed Outbreak of Rubeola-Rubella in District Kangra of Northern India

BACKGROUND: On 14(th) September 2006, a local community leader informed us about the sudden increase in number of cases of fever and rash in five villages of district Kangra. We investigated the suspected outbreak to confirm the diagnosis and recommend for prevention and control. MATERIALS AND METHODS: We defined a case of rubeola as the occurrence of fever with rash in children from 3(rd) September to 13(th) January, 2007. We collected information on age, sex, date of onset, residence, signs, symptoms, vaccination and cold chain status. We described the outbreak by place, time and person characteristics. We conducted a retrospective cohort study to estimate vaccine efficacy (VE). We ascertained the measles immunization status by interviewing the mothers and reviewing immunization cards. We confirmed diagnosis clinically, epidemiologically and serologically. RESULTS: We identified 60 case patients in five villages (41/60 rubeola and 11/60 confirmed epidemiologically linked unvaccinated rubella). The overall attack rate (AR) was 9%. Sex specific AR was 11% for male. Majorities of cases were >5 years of age. No death/minimal complications have occurred. Of 60 case-patients, 42 (70%) were vaccinated for rubeola. The AR of rubeola among unvaccinated children was 25.8% as compared to AR among vaccinated of 4.5% (relative risk: 5.75%; 95% confidence interval: 3.48-9.51 P < 0.001). We estimated general VE to be 83% while gender based VE for male was 84%. Eight case-patients were confirmed serologically for measles immunoglobin M antibodies, two nasopharyngeal swabs positive by polymerase chain reaction. Rubeola virus was genotyped D4. Only 30% (18/60) of the cases took the treatment from modern system of medicine. CONCLUSION: A mixed outbreak of rubeola/rubella was confirmed clinically, epidemiologically and serologically. We recommend measles and rubella (MR) vaccination at the age of 18-24 months and aggressive Information, Education and Communication (IEC) activities to modify help seeking behavior of the community, especially in the measles affected areas.