Headache after vaccination against COVID-19 – On Medicine – BMC Blogs Network

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Headache is a common disorder and head pain is a common experience in the lives of almost everyone. The prevalence of headache within one year is 43% in people aged below 50, and on a given day, 6-17% of persons of any age may experience headache. Like all vaccinations, including those aimed to protect against SARS-CoV-2 (the virus responsible of COVID-19), there may be side effects.

Our latest systematic literature review with meta-analysis assesses the occurrences of developing headache after COVID-19 vaccination. Our results are based on 84 clinical trials testing the efficacy, effectiveness and safety of the vaccines that have been developed between 2020 and 2021, for a total of 1.57 million persons receiving one vaccine or a placebo.

In the week after the first administration, 22% of vaccine recipients developed headache while 10% among placebo recipients reported headache. After the second administration, these percentages raise to 29% and to 12% among vaccine and placebo recipients, respectively. Headache is the third most common side effect the most common being pain at injection site.

Generally, duration of headache onset within the first day from injection is below 24 hours, of a moderate intensity, and benefits from treatment with acetylsalicylic acid. It is bilateral (i.e. on both sides of the head) in 7075% of the cases, and 3040% of the patients describe a pulsating quality. Aggravation with activity is the most common accompanying symptom, followed by phono/photophobia (i.e. being bothered by light and noise) and nausea.

Taken as a whole, the features of such a headache do not resemble migraine-like headache in most of the cases; however, in approximately one third of the cases, migrainous features seem to be met, and this appears to be much more common among people with pre-existing migraine.

The causes of headache after vaccination against SARS-CoV-2 are poorly understood. However, it seems to related to a systemic inflammatory response with a still unclear mechanism, and it is a reversible mechanism: in other words, it will resolve in few hours.

Very few anecdotal exceptions to this common non-severe and reversible post-vaccination headache have been described as case reports of complications of vaccination, specifically as cases of cerebral venous thrombosis associated with vaccine-induced immune thrombotic thrombocytopenia (VITT). The main differences from the normal vaccine-associated headache lies in the delayed onset (5-10 days), and headache being described as severe, progressive and treatment-resistant.

In sum, headache is a common side effect of vaccination after SARS-CoV-2, and it is almost always a non-severe effect. It presents within the first day and resolves within a day with bed rest or acetylsalicylic acid in 18-27% of the cases after the first dose, and in 23-35% after the second dose. It may have migrainous features in around a third of the cases, particularly among persons who already suffer from migraine.

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Headache after vaccination against COVID-19 - On Medicine - BMC Blogs Network