Can COVID-19 Vaccination Reduce Hepatitis B Viral Load?

Unlike other strains of hepatitis, there is a vaccine for hepatitis B (HBV) that enables most infected individuals to clear the virus in fewer than 6 months. However, infections that last 6 months or longer are classified as chronic hepatitis B.

In the US, approximately 1.59 million people are living with chronic hepatitis B, due to their immune system’s inability to fight off the virus. For these individuals, the primary objective is to clear hepatitis B surface antigen (HBsAg) from the blood, as a high level of HBsAg has been correlated with antigen-specific immunotolerance.

Pegylated interferon and nucleos(t)ide analogs are commonly utilized to suppress HBV replication and reduce HBsAg in chronic hepatitis B patients, but rarely eliminate the virus.

A recent study, published in Internal Medicine, examined an unexpected potential side effect of the COVID-19 vaccine: HBsAg reduction in patients with chronic hepatitis B.

The investigators studied 3 clinical cases in Japan, in which chronic hepatitis B patients had a rapid decrease in their HBsAg levels after receiving a COVID-19 vaccine. All analyses with patient data were approved by the institutional research ethics committees of the International University of Health and Welfare.

To determine whether there really was a correlation between COVID-19 vaccination and HBsAg reduction, the investigators compared the number of chronic HBV patients who had a change in HBsAg levels before Japan’s COVID-19 vaccine rollout to the number of HBV patients who showed a change in HBsAg levels after COVID-19 vaccination.

A total of 107 patients were included in the analysis comparing HBsAg changes in the pre-vaccination period with the post-vaccination HBV patients. Among these, 11 patients had an HBsAg reduction of >50% per year during the post-vaccination period, 50 had a 10%-50% reduction, and 46 had a <10% decrease or an increase in HBsAg levels.

The proportion of patients whose HBsAg levels reduced by more than 50% per year was notable after the rollout of COVID-19 vaccines. At P = 0.0532, the role of COVID-19 vaccination in HBsAg reduction was not statistically significant. However, the study authors concluded, it suggests “the administration of COVID-19 vaccines may have been involved in HBsAg reduction in patients with chronic hepatitis B,” and certainly merits further investigation.