[Potential Impact of Public Communication on Emergency Presentations due to Headache during the Covid-19 Pandemic]

Headache is a frequent presenting symptom in the emergency department. While most cases are of benign aetiology, it is crucially important to identify potentially dangerous underlying disorders. We hypothesized an increase in headache-related emergency presentations after venous thrombosis of cerebral sinuses had been identified as a rare side effect of vaccination with adenovirus vector-based Coronavirus-disease 2019 (COVID-19) vaccines and that information had been publicly communicated by the Paul Ehrlich Institute. Data from patients with the diagnosis of primary headache disorders or unspecified headache presenting to the Interdisciplinary Emergency Department of the University Medicine Mannheim were retrospectively analysed. Based on vaccination dashboard data published by the Federal Ministry of Health, calendar weeks 14-30 and 47-48, on the one hand, and 1-13 and 31-46, on the othe, were categorized into a variable "vaccination epoch" (14-30, 47-48: high vaccination activity if≥3 million weekly vaccinations in Germany; 1-13, 31-46: low vaccination activity if<3 million weekly vaccinations). The number of patients with headache was the dependent variable. A Poisson regression was performed to analyze whether the frequency of events, i. e., patient presentations, was a function of year (2019, 2021), epoch (high, low) and an interaction of year and epoch - the latter reflecting an impact of vaccination activity during the pandemic and expressed as incidence rate ratio. Compared to 2019, there was a more than 70% increase in presentations due to headache during periods of high vaccination activity in 2021 (p<0.001; 95% confidence interval 1.272-2.316), in 25% of presentations in 2021, patients considered their headache as vaccination-associated. Public communication and resulting nocebo effects may, among other factors, have contributed to our observation of increased numbers of emergency headache presentations, illustrating the impact of public distribution of medical information on practical aspects of emergency care during crises.