Covid-19 vaccine: Blood-clot risk rarer than a double lightning strike

SundayTimes – You have a greater chance of being struck by lightning – twice – than getting a blood clot from a Covid-19 vaccine.

“To stop the vaccinations and put our health-care workers at risk is unethical and not the correct thing to do,” said Wits professor Barry Jacobson, president of the SA Society of Thrombosis and Hemostatis, after the Johnson & Johnson vaccine rollout to health workers was suspended on Tuesday.

The move followed a pause in administration of the J&J vaccine by the US Food and Drug Administration (FDA), to give it time to investigate the risk of very rare (one to four people in a million) and unusual blood-clotting disorders that could be linked to the jabs.

None of the 292,623 health workers vaccinated in SA has developed severe clotting.

Jacobson said: “I have treated doctors who have died from Covid-induced thrombosis … there is no science or ethics to this suspension. People should fight to continue with the vaccinations.”

A new study by Oxford University scientists shows people have an eight times greater risk of developing severe cerebral blood clots from Covid-19 than from the Oxford/AstraZeneca vaccine.

About 40 people in a million developed cerebral blood clots in the two weeks after a Covid-19 infection and about eight died, the researchers found. In comparison, about four to five people in a million who got the AstraZeneca vaccine were at risk of clots.

About 500,000 cases of Covid-19 in the US were analysed for the latest study, which has yet to be peer reviewed.

SA’s decision to suspend its vaccinations followed the FDA pause sparked by blood clots in six out of 6.8-million Americans who had the J&J vaccine, one of whom died.

The SA Medical Research Council said: “Some countries, like France and Poland, have weighed the risks and chosen to continue to provide the J&J vaccine while this rare side-effect is considered.

“The US has suspended use of the J&J vaccine for now but in a context where 37% of their population have already received one vaccination, and where alternatives are readily available.”

Dr Keith Cloete, head of health in the Western Cape, said the J&J vaccine was made available in SA under trial conditions. “When the FDA announces a pause, our science institutions and ethics committees are virtually bound by that decision.”

Professor Linda-Gail Bekker, co-principal investigator of the Sisonke implementation study, which has been delivering the J&J vaccines, said: “We had a very good meeting with Sahpra [ SA Health Products Regulatory Authority] and there is … urgency on this.”