The U.S. Centers for Disease Control this morning recommended that states pause administration of the Johnson & Johnson/Janssen Pharmaceuticals COVID-19 vaccine, over what it described as an “abundance of caution” following a handful of cases of severe blood clotting. The pause is expected to last just a few days as the CDC and the Food and Drug Administration review data on those cases.
The overall risk of any adverse reaction to the J&J vaccine appears to be vanishingly small. The six cases that are the focus of CDC and FDA concern arose from more than 6.8 million vaccinations. Of those six cases, one patient died, and another remains hospitalized in critical condition.
Despite the tiny risk, if you’ve already received the J&J vaccine, you may be wondering if you should be concerned.
“For people who got the vaccine more than a month ago, the risk to them is very low at this time,” said CDC Deputy Director Anne Schuchat, MD, in a call with the press this morning. Of the six cases being reviewed, all occurred within six to 13 days of vaccination.
Schuchat did recommend, though, that people vaccinated within the last two weeks watch for symptoms including severe headache, abdominal pain, leg pain, or shortness of breath, which could be early warning signs of clotting. Schuchat recommended contacting your health care provider if these symptoms surface.
These symptoms are distinct from the flu-like symptoms often experienced as a side effect of vaccination. In particular, FDA researcher Peter Marks emphasized this morning that mild headaches are a common post-vaccination side effect, while only severe headache is a cause for concern of possible blood clotting.
Though the CDC and FDA have not laid this out explicitly, risk appears to be concentrated among women under 50 who recently received the J&J vaccine. All six cases of blood clotting occurred in women between the ages of 18 and 48.
Perhaps most important, if you do feel you need medical attention, be sure your health care provider knows you were recently vaccinated with the J&J vaccine. That’s because one common treatment for blood clotting, heparin, can cause serious harm if used to target the type of blood clotting seen in the six cases being investigated, according to Marks.
Finally, J&J’s vaccine is based on the same underlying adenovirus technology as the AstraZeneca vaccine, which has had similar clotting issues, also concentrated among women. Though speculative, investigation of the AstraZeneca clotting incidents is looking in part at possible interactions with birth control medications, which can also create blood-clotting risk.
Marks of the FDA this morning said there is no current evidence of a link between birth control medications and reactions to the J&J vaccine, but also that more cases and evidence could emerge.
