Risk of gout flares after COVID-19 vaccination: A case-crossover study

OBJECTIVE: Routine vaccinations are associated with an increased risk of gout flares. We examined the association between COVID-19 vaccination, an immunization program implemented to a large proportion of population, and the risk of gout flares. METHODS: We conducted a time-stratified case-crossover study among patients with gout who experienced gout flares between December 2020 and September 2021, using data from The Health Improvement Network. We compared the risk of gout flares on each of the seven days on and after the day of COVID-19 vaccination vs. no vaccination during that period using conditional logistic regression. In addition, we performed subgroup analyses stratified by different COVID-19 vaccines (i.e., BNT162b2, hereafter referred to as BNT, and ChAdOx1 nCov-19, hereafter referred to as ChAd). RESULTS: Among 5,904 patients with gout (mean age: 63·1 years; 85·5% male) who experienced gout flares within one month, the risk of gout flares slightly increased on the second day after COVID-19 vaccination (odds ratio: 1·44; 95% CI: 1·02 to 2·07). The risk of gout flares also slightly increased after receiving COVID-19 vaccine on other remaining days (ORs ranged from 1·03 to 1·22); however, none of them was statistically significant. An increased risk of gout flares on the second day after vaccination was mainly observed for the ChAd vaccine (odds ratio: 1·44; 95% CI: 1·00 to 2·05), but not for BNT vaccine (odds ratio: 1·18; 95% CI: 0·67 to 2·02). CONCLUSION: COVID-19 vaccination, mainly ChAd vaccination, slightly increases the risk of gout flares on the second day after vaccination. This finding reassures the safety of COVID-19 vaccination for patients with gout.