Influenza and herpes zoster vaccine effectiveness in autoimmune or immune-mediated diseases

Individuals with autoimmune or immune mediated diseases (AID) are more susceptible to infections and often experience worse outcomes if infected, underscoring the importance of vaccination. However, it remains unclear whether vaccine effectiveness (VE) differs between persons with and without AID. Our aim was to compare the effectiveness of influenza and herpes zoster vaccines in both groups, where the AID group consists of individuals with either multiple sclerosis (MS), chronic inflammatory bowel disease (IBD) or chronic inflammatory rheumatic disorders (CIRD).

We emulated five target trials using claims data from a large German health insurance provider: one for herpes zoster and four for influenza across different seasons. We used 1:1 balanced risk set matching and Cox proportional hazards models with interaction terms between vaccination status and AID status to estimate VE and differences in VE across groups.

For the herpes zoster trial, 169,054 vaccinated individuals were matched to the same number of controls, including 10,994 AID individuals per group. Herpes zoster VE was 68.73 (95% CI 55.75-77.91) in the AID group and 60.30 (55.59-64.52) in the non-AID group (VE ratio: 1.14, 95% CI 0.93-1.30). Across four influenza seasons (2015/2016-2018/2019) between 1403,342 and 1713,064 individuals were included, including between 56,662 and 78,320 AID individuals. Influenza VE varied by outcome, season, and assumptions, but VE ratios remained near one in most analyses (VE ratios: -0.92-3.77), with all CIs including one.

There was no evidence that VE differs meaningfully between individuals with and without AID, conditional on the included confounders. Both vaccines were similarly effective across groups, suggesting that VE is not reduced in MS, IBD, or CIRD patients. Further research is necessary to validate these findings for other AID and infections.