Together let us confront it: An outbreak investigation of hepatitis B in Pathanamthitta district, Kerala

Hepatitis B is a potentially life-threatening liver infection caused by the Hepatitis B virus (HBV). The established routes of transmission are from mother to infant, sexual contact, and exposure to blood or body fluids. Though HBV is preventable by vaccine and robust infection control practices, outbreaks of HBV infection do occur in India. However, the state of Kerala with its health parameters, one among the best in the country, cannot afford to have continuing outbreaks. An unusual increase in the reported cases of Hepatitis B in a rural area of Pathanamthitta district of Kerala, called for an outbreak investigation.

To describe the epidemiological features, to determine the risk factors associated with HBV transmission, and to suggest measures to prevent future transmission.

A community-based case-control study (1:2) was undertaken. A total of 162 participants (54 cases and 108 age, gender, and neighborhood matched controls) took part in the study. Focus group discussions were conducted with subject experts to develop an interview schedule assessing 40 risk factors. It was further reviewed by the University of Sydney. Data was collected by trained Junior Health Inspectors and Junior Public Health Nurses of the Primary Health Centers. Data was analyzed using SPSS v. 20. Proportions were compared by Univariate analysis, sub-group analysis, and logistic regression. Population Attributable Risk (PAR) was also calculated.

More than 90% of the infections were IgM anti-HBc positive, suggesting a recent infection. Interventions during hospitalization [OR: 7.98 (95% CI - 2.17--29.4)], family history of Hepatitis B [OR. 4.14 (95%CI - 1.73--9.9)], and laboratory investigations [OR: 3.99 (1.72--9.31)] were found to be significant risk factors. PAR was highest for laboratory interventions (32%). Vaccinating household contacts and strict enforcement of infection control practices could substantially reduce the burden of this fatal disease.