Headache Following COVID-19 Vaccination Among Healthcare Employees With a History of COVID-19 Infection: a Cross-sectional Study in Iran With a Meta-analytic Review of the Literature

Abstract Background: There is strong evidence of headaches following COVID-19 vaccination using any type of vaccine. However, very few studies have examined the headache characteristics and their determinants, especially among healthcare employees who have previously experienced COVID-19 infection. We evaluated and compared the incidence of headache following injection of common types of COVID-19 vaccines to determine factors related to its incidence following vaccination among Iranian healthcare employees who had contracted and recovered from the virus.Methods: A group of 334 employees who had contracted COVID-19 of different intensities were vaccinated with different types of COVID-19 vaccine at least one month following recovery from the virus. They were assessed for baseline information, type of vaccine received, and relevant headache characteristics. Results: Overall, 39.2% of participants reported post-vaccination headache. Of those who reported a previous history of headache, migraine was reported by 51.1%, tension-type by 27.4%, and other types by 21.5%. The mean time between vaccination and the onset of headache was 26.78 ± 6.93 h, indicating that headache onset was less than 24 h after vaccination in most participants (83.2%). The headache reached an estimated peak at 8.62 ± 2.41 h. Most participants reported a pressure-type headache. The prevalence of post-vaccination headache differed significantly according to the type of vaccine. The highest rates were reported for AstraZeneca, followed by Sputnik V. Multivariate logistic regression analysis showed that the vaccine brand, being female in gender, and the initial COVID-19 severity were the main determinants for predicting post-vaccination headache. Conclusion: It should be expected that about one-third of healthcare employees will experience headache following COVID-19 vaccination. This is more likely to occur in females and those who have recovered from severe cases of COVID-19.