Epidemiological aspects of headache after different types of COVID‐19 vaccines: An online survey

Background Coronavirus disease 2019 (COVID‐19) vaccine–related side effects are a key concern with the emergence of various types of vaccines in the market. We aimed to assess the frequency and characteristics of headache following different types of COVID‐19 vaccines. Methods Fully vaccinated people were recruited by a convenience sample through an online survey from September 1 to December 1, 2021. Detailed analysis of headache following vaccination was investigated. Participants with a history of pre‐existing headaches were telephone interviewed by a neurologist to ascertain the type of headache. Results A total of 1372 participants participated (mean age 32.9 ± 11.1). The highest frequency of headache was reported with the adenoviral vector type (302/563, 53.6%), followed by mRNA vaccines (129/269, 48%) and then the inactivated type (188/540, 34.8%). Recipients of the adenoviral vector type had a significantly longer latency between vaccination and the headache onset (median 8 h [5:12]) than recipients of the inactivated type (median 4 h [2:8], p