Being vaccinated against hepatitis B may reduce chronic inflammation levels in the body, which could help ward off diabetes
By Carissa Wong
2 September 2025
Immunisation against hepatitis B is routinely offered across much of the world
Mehmet Salih Guler / Getty Images
The hepatitis B vaccine seems to reduce the risk of developing diabetes, and not just by preventing the infection.
The vaccine is routinely offered to infants in most countries, usually via three doses. In the US, this became part of the vaccination programme in 1991, so only about 30 per cent of adults had full coverage in 2018.
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Scientists have previously found the vaccine appears to cut the risk of diabetes. This may be due to the hepatitis B virus – which infects the liver and spreads through blood, semen and vaginal fluids – disrupting the organ’s ability to store sugar from the blood. This could raise the risk of diabetes, where blood sugar levels are persistently too high.
But prior studies have not looked at whether the vaccine might reduce diabetes risk among a group of both immunised and non-immunised people who haven’t contracted hepatitis B, which would suggest the effect acts independently of just preventing the infection.
To explore this, Nhu-Quynh Phan at Taipei Medical University in Taiwan and her colleagues analysed the health records of more than 580,000 people living across the US, Europe, Africa, Latin America, the Middle East and the Asia-Pacific. On average, these records spanned nearly four years for each individual between 2005 and 2023.