Altered liver function test after Covid-19 vaccines: A retrospective control group study

Area of Science:

• Hepatology
• Vaccinology
• Public Health

Background:

• Liver injury has been anecdotally reported post-COVID-19 vaccination.
• The incidence and comparative risk of liver test alterations following COVID-19 vaccination remain unclear.

Purpose of the Study:

• To compare the cumulative incidence of new-onset liver test abnormalities after COVID-19 vaccination.
• To compare these alterations against an historical control group that received influenza vaccination.

Main Methods:

• A retrospective cohort study was conducted.
• Adults receiving COVID-19 vaccines (Jan-May 2021) were compared to those receiving influenza vaccines (2019).
• Liver function tests were analyzed for new onset alterations within 90 days.

Main Results:

• The study included 29,798 in the COVID-19 vaccine group and 24,605 in the influenza vaccine group.
• The cumulative incidence of new liver enzyme test alterations at 90 days was 4.7 per 1000 for COVID-19 vaccines versus 5.1 per 1000 for influenza vaccines (p=0.489).
• Two cases of potential immune-mediated liver injury were observed in the COVID-19 vaccine group.

Conclusions:

• No significant difference in liver test alterations was found between COVID-19 and influenza vaccine recipients.
• These findings suggest COVID-19 vaccines are safe regarding liver function.
• While immune-mediated liver injury cases were noted post-COVID-19 vaccination, causality remains undetermined due to insufficient data.