“BOSTON — It promised convenience, ease of storage and protection against serious COVID-19 illness. And by all accounts, Johnson & Johnson/Janssen’s single-dose vaccine is living up to those claims. But is all that coming with a price?
U.S. regulators now have the difficult task of figuring out whether six cases of cerebral blood clots that developed just weeks after immunization are an actual side effect of the vaccine.
“In the general population this condition exists in the absence of vaccination and is a very rare condition,” said Dr. Mark Poznansky, director of Mass General’s Vaccine and Immunotherapy Center. “When you start vaccinating lots of people, you can get these sort of findings. And it’s really incumbent upon the FDA to work out is it cause or is it just a random association?””