Stroke ‘exceedingly rare’ after COVID-19 vaccination

Strokes were reported to be a rare adverse event following the administration of a COVID-19 vaccine, according to a study in Neurology.

Using data provided by the Mexican Ministry of Health, Diego Lopez-Mena, MD, of the National Institute of Neurology and Neurosurgery in Mexico City, and colleagues conducted a nationwide retrospective, descriptive study that analyzed stroke incidence per million COVID-19 vaccine doses administered in hospitalized adults from December 2020 to August 2021. Strokes were reported only if they were confirmed within the first 30 days after vaccination.

During the study, 79,399,446 doses of six different COVID-19 vaccines from Pfizer/BioNTech, AstraZeneca, Sinovac Biotech, CanSino Biologics, Johnson & Johnson and Sputnik V were administered.

A total of 28,646 adverse events occurred within the first 30 days. Of those, 27,968 (98%) were classified as non-serious, and 56 were confirmed as stroke (8.2% of serious adverse events; 55.5% women; median age, 65 years). Overall, stroke incidence was 0.71 cases per 1,000,000 administered doses (95% CI, 0.54-0.92), and the median time from vaccination to stroke was 2 days (interquartile range = 1-5 days).

Further, the most frequent type of stroke was acute ischemic stroke, which occurred in 43 of the 56 patients (75%; incidence rate = 0.54 per 1,000,000; 95% CI, 0.40-0.73); nine strokes were intracerebral hemorrhages (16.1%; IR - 0.11 per 1,000,000; 95% CI, 0.06-0.22). The most common risk factors were hypertension (58.9%) and diabetes mellitus (39.3%).

“Our observations suggest that stroke remains an exceedingly rare event among recipients of six different vaccines against SARS-CoV-2,” the researchers wrote. “Further research is still needed to analyze the potential causal associations between stroke and the different vaccines against SARS-COV-2 vaccines currently available worldwide.”