Brain clots more rife after virus

CEREBRAL venous thrombosis (CVT), or a brain blood clot, is far more likely to occur after a Covid-19 infection than after vaccination with Pfizer or Moderna, according to a study out of Singapore.

CVT is an extremely rare but possible side effect of the mRNA vaccines, so researchers used Singapore hospital data to estimate the rate of the condition after vaccination and compare it with the rate after Covid-19.

The researchers say six CVT cases were identified among just over 60,000 Covid-19 patients, and nine CVT cases were identified among three million people vaccinated with Pfizer or Moderna.