Endocrine Abstracts

Objective: Vaccination against coronavirus disease 2019 (COVID-19) an important component of coping with the pandemic. Anecdotal cases and case series reported an association between COVID-19 vaccination and the development of Graves’ disease. We used data from Israel’s largest health care organization to determine whether COVID-19 vaccination was associated with the incidence of Graves’ disease.

Methods: We analyzed data from Clalit Health Services (CHS), which insures 4.7 million patients. A population-based, matched, case-control study was performed. Cases were defined as adult patients diagnosed with Graves’ disease between December 2020 and November 2022. Each case was matched in a ratio of 1:2 with control based on age, gender, and autoimmune disease. Each control was assigned an index date which was identical to that of his/her matched case, which was defined as the date of Graves’ disease diagnosis. Time between vaccination date and the diagnosis of Graves’ disease/index date was assessed.

Results: A total of 726 patients with Graves’ disease were matched with 1452 controls. The median age of the cohort was 40 (interquartile range, 30-53) years, and 25.5% (555/2178) were men. Similar proportions of study patients and controls have received the first, the second and the third dosage of COVID-19 vaccine. Positive test for COVID-19 was detected in 21.2% (154/726) of Graves’ disease patients and 19.4% (282/1452) of controls (P=0.33). In a univariate analysis, first COVID-19 vaccine was not associated with the incidence of Graves’ disease [odds ratio 95% confidence interval: 1.15 (0.92-1.43)]. The mean time between first COVID-19 vaccination and the diagnosis of Graves’ disease for cases or index date for controls was not significantly different [275.69 days (standard deviation 144.37) for cases compared to 275.45 days (standard deviation 145.76) for controls].

Conclusions: We have found no association between COVID-19 vaccination and the incidence of Graves’ disease. Our study adds data to the thyroid safety of COVID-19 vaccine.