On Tuesday, regulators recommended pausing the rollout of Johnson & Johnson ’s Covid-19 vaccine out of “an abundance of caution” after six out of nearly 7 million recipients developed dangerous blood clots.
For one of the regulators, the U.S. Food and Drug Administration, the decision was entirely in character: it has always put a premium on safety. That doesn’t necessarily make it the safe choice. Covid-19 infects more than 60,000 Americans and kills more than 900 every day. A pause of even a few days could add to that toll.
“It’s very clear that the dangers of Covid are much larger than the dangers of the J&J vaccine or the AstraZeneca vaccine for that matter,” said Alex Tabarrok, an economist at George Mason University who has advocated for bolder approval and distribution of vaccines. “I worry that the public will confuse a pause to mean that the FDA thinks people shouldn’t take the J&J vaccine.”
It’s too soon to know the ultimate net effect of the pause on health. Still, Britain kept administering AstraZeneca’s vaccine when similar blood clotting was reported and the evidence so far seems to back it up.
The Winton Center for Risk and Evidence Communication, based at the University of Cambridge, estimates the virus is a much bigger risk than blood clots to recipients of almost all ages and exposures. In every 100,000 people in their 40s with low exposure to the virus, the vaccine will cause blood clots in 0.5 while preventing Covid-19 serious enough to require intensive care in six others, it says. Among people in their 60s with high exposure, the vaccine would cause blood clots for 0.2 while preventing an ICU visit for 128. Only for people in their 20s with low exposure did it find risks are roughly equal. British regulators have advised that people under 30 be offered a different vaccine.
