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.

The heterogeneity of measles epidemiology in India: implications for improving control measures.

BACKGROUND: Measles vaccination coverage varies in India. Trainees of the Field Epidemiology Training Programme (FETP) investigated 8 outbreaks from 2004 through 2006 in Himachal Pradesh, Uttaranchal, Tamil Nadu, and West Bengal. We reviewed these outbreaks to contribute to the description of the epidemiology of measles and propose recommendations for control. METHODS: FETP trainees searched for measles cases through stimulated passive surveillance or door-to-door case search; estimated attack rates, case fatality, and the median age of case patients; interviewed mothers about vaccination status of their children; and collected serum samples for immunoglobulin M serological testing whenever possible. For 3 outbreaks, the trainees estimated the vaccine efficacy for children >12 months of age through cohort studies. RESULTS: Six of the 8 outbreaks were serologically confirmed. Compared with outbreaks in other states, outbreaks in states with vaccination coverage of >90% had a higher median age among case patients and a lower median attack rate. Six deaths (case fatality rate, 1.5%) occurred during the 5 outbreaks for which vitamin A was not used. The vaccine efficacy was 84% (95% confidence interval [CI], 74%-91%) in Himachal Pradesh. In West Bengal, it was 66% (95% CI, 44%-80%) in 2005 and 81% (95% CI, 67%-89%) in 2006. CONCLUSIONS: In states with higher coverage, attack rates were lower and case patients were older. Although states with coverage of <90% should increase 1-dose coverage and address coverage in pockets that are poorly reached, a second opportunity for measles vaccination could be considered in states such as Himachal Pradesh and Tamil Nadu. Use of vitamin A for case management needs to be generalized.

Two Highly Immunized Hilly Areas versus Double Measles Outbreak Investigations in District Kangra, Himachal Pradesh, India, in 2006.

BACKGROUND: We investigated two sequential outbreaks of measles in seven villages of Kangra, to confirm the diagnosis and to formulate recommendations for prevention and control. METHODS: We defined a case of measles as occurrence of fever with rash in a child aged six months to 17 years during the period 3(rd) September to 23(rd) November 2006. We collected information on age, sex, residence, date of onset, symptoms, signs, treatment taken, traveling history and vaccination status. We described the outbreak by time, place and person. We estimated vaccine coverage and efficacy in the affected villages. We confirmed diagnosis clinically, serologically and through genotyping of the virus. RESULTS: We identified 69 cases. Overall attack rates ranged between 4.2% and 6%. All case patients were between 6 years to 11 years of age. Age-specific attack rate in double outbreaks ranged in between 1.7% and 21.6%, the highest being in the age range 11-17 years. No deaths or complications were reported. The epidemic curve was suggestive of typical propagated pattern. The first outbreak imported virus after an interschool game competition (relative risk, 6.44%; 95% confidence interval, 3.81-10.91); followed by the second outbreak, in which people exchanged foods in the festival in one infected village of the first outbreak (relative risk, 5.3; 95% confidence interval, 1.90-14.77; P <.001). The calculated immunization coverage (93%) coincided nearly with administrative claims. The vaccine efficacies were estimated to be 85% and 81% in the first and second outbreaks respectively. Eleven of the 16 case patients were tested for measles IgM antibodies, while two nasopharyngeal swabs were positive by polymerase chain reaction (PCR) and are genotyped D4 measles strain. Vitamin A supplementations were only given in four villages. CONCLUSION: Measles outbreaks were confirmed in high-immunization-coverage areas. We recommended (i) second dose opportunity for measles in Himachal Pradesh and (ii) vitamin A supplementation to all the case patients.