Unmasking COVID-19 Headaches: Phenotypic Continuity in Infection, Reinfection, Vaccination and Post-COVID Syndrome

Background: Headache is a common symptom during SARS-CoV-2 infection that can persist beyond three months. Both tension-type and migraine-like headaches have been described during SARS-CoV-2 infection and immunization. Objective: The main objective is to characterize the headache phenotype during SARS-CoV-2 infection and to examine its relationship with headache recurrence following reinfection and COVID-19 vaccination. As secondary endpoints, we evaluated the characteristics of primary headache according to the COVID-19 headache profile and studied potential predictors of persistent headache following COVID-19. Results: 109 patients were included, 86.2% women, mean age 45.3 years (SD: 2.5). COVID-19 headache met the International Classification of Headache Disorders (ICHD-3) criteria for tension-type headache in 49.5% (54/109) and for migraine in 12.8% (14/109). Headache recurrence occurred in 62.5% (15/24) of patients upon reinfection and in 59.2% (61/103) following vaccination. Among all participants, 77.9% (85/109) had a prior diagnosis of primary headache: 25.9% (22/85) with migraine and 47.1% (40/85) with tension-type. The phenotype of COVID-19 headache (migraine-like or tension-type) tended to resemble the patient's pre-existing headache pattern during both reinfection and after vaccination. Additionally, 22.9% (25/109) experienced post-COVID-19 headache, which was associated with fibromyalgia and obesity. Conclusions: Our findings suggest that the COVID-19 headache profile is closely related to the patient's pre-existing primary headache and is associated with reinfection and post-vaccination.