Hepatitis B surveillance in Singapore

Area of Science:

• Epidemiology
• Infectious Diseases
• Public Health

Background:

• Hepatitis B virus (HBV) infection posed a significant public health challenge in Singapore during the study period.
• Acute viral hepatitis cases reported between 1977 and 1979 revealed that HBV constituted approximately one-third of all cases.

Purpose of the Study:

• To analyze the epidemiology of acute hepatitis B in Singapore.
• To identify high-risk demographic groups and geographical areas.
• To investigate potential transmission routes of HBV.

Main Methods:

• Retrospective analysis of 257 reported cases of acute hepatitis B.
• Calculation of morbidity, mortality, and case-fatality rates.
• Examination of age, ethnicity, sex, and geographical distribution.
• Investigation of outbreak-specific transmission factors.

Main Results:

• Mean annual morbidity and mortality rates were 4.4 and 0.12 per 100,000, respectively, with a case-fatality rate of 2.7%.
• Highest morbidity rates were observed in the 15-34 year age groups and among the Indian ethnic population.
• Males (4.6:1 ratio) and individuals in densely populated urban/suburban areas were disproportionately affected.
• Outbreaks were linked to contaminated needles (medical and tattoo) and close contact transmission.
• Parenteral procedures were associated with infection (p < 0.005), but non-parenteral or inapparent parenteral transmission was also significant.

Conclusions:

• Hepatitis B infection was endemic in Singapore, with specific demographic and geographic patterns.
• While parenteral transmission is a risk factor, non-parenteral routes likely play a substantial role in HBV spread.
• Further research into perinatal transmission and vector involvement is recommended to understand disease endemicity.