No doubt you have heard that the Johnson & Johnson vaccine hit a speed bump this week. The FDA and the CDC tapped the brakes on this single-dose COVID shot. That’s because of several cases of dangerous blood clots linked to this vaccination. Yesterday we listened to the hearings of the Advisory Committee on Immunization Practices(ACIP) at the CDC. Is the decision to continue the J&J vaccine pause appropriate or a boondoggle? Will the delay discourage millions from getting a COVID-19 vaccination?
AstraZeneca and the J&J Vaccine Pause:
The joint CDC and FDA action in pausing the administration of the Johnson & Johnson COVID vaccine is highly controversial. Approximately 7 million people have received this shot. As of this week it was reported that 6 women had developed dangerous blood clots. One died. Another was listed in critical condition.
Since the initial report, two more cases were added to the list. Another woman and a man also developed blood clots.
The AstraZeneca vaccine, which is not approved or used in the US, is also associated with serious blood clot reactions in rare cases. The New England Journal of Medicine (April 9, 2021) published two articles accounting for 16 patients who suffered blood clots in the brain after getting this vaccine.
What’s Causing the Blood Clots?
The condition is called cerebral venous sinus thrombosis (CVST or CVT for short). Researchers wonder whether some patients may be making antibodies to platelet factor 4 after getting these two vaccines. This rare event might be leading to the blood clots.
Dr. Paul Offit is a leading authority on vaccines. He sits on the FDA’s vaccine advisory committee and has been a frequent guest on our syndicated public radio show (Show 1236: The Inside Story on Vaccines Against COVID-19). Dr. Offit wants to know why some vaccines might trigger the body’s immune system to create antibodies to platelet factor 4.
Both Johnson & Johnson as well as AstraZeneca use a viral vector, an inactive adenovirus, in the vaccines instead of mRNA like the Moderna and Pfizer vaccines. Dr. Offit has asked if there is something about the adenovirus that is part of the problem. The FDA has been quick to point out that it has received no reports of CVST associated with the Moderna or Pfizer/BioNTech vaccines.
Blood Clots are Rare, So Why Institute the J&J Vaccine Pause?
Many people are confused about why the health authorities would have stopped administration of an effective vaccine in the face of a surge in cases. The FDA has suggested that they are pausing out of an “abundance of caution.”
Some experts applaud the decision as prudent, bolstering public trust while the agency investigates. The CDC believes this action will alert patients and health professionals to the clotting concern and encourage them to report any additional cases. Otherwise, cases might have gone unnoticed and unreported.
If many people have also experienced life-threatening blood clots after getting the one-shot vaccine, the pause will have been worthwhile. If there are no more cases, the J&J vaccine pause will likely be lifted within a week.
Symptoms to Watch Out for:
In Europe, public health authorities have warned people who got the Astra-Zeneca vaccine to be alert for symptoms such as blurred vision or a severe headache that doesn’t go away. Other potential signs of a clot include abdominal and/or leg pain and shortness of breath.
Tempest in a Teapot?
Other specialists believe the FDA is putting people at risk by pausing the roll-out of a crucial vaccine when it doesn’t even know whether the blood clot complication is actually caused by the shot. After all, the risk of blood clots from smoking is 1 in 600. One in 1,000 women on birth control pills develop clots.
As of yesterday, it is estimated that 7.4 million Americans have received the single-shot J&J vaccine. At the time of this writing there have been 8 cases of CVST. That is an exceedingly small risk.
Even COVID-19 itself causes blood clots and they are not rare. A study released on April 15, 2021 suggests that people who come down with COVID-19 are at much higher risk for developing blood clots than people who get the AZ vaccine.
The lead author, Dr. Paul Harrison of the University of Oxford, describes the research:
“We’ve reached two important conclusions. Firstly, Covid-19 markedly increases the risk of CVT, adding to the list of blood clotting problems this infection causes. Secondly, the Covid-19 risk is higher than we see with the current vaccines, even for those under 30; something that should be taken into account when considering the balances between risks and benefits for vaccination.” (Barron’s, April 15, 2021).
The People’s Pharmacy Perspective:
The J&J Vaccine pause is prudent. We should know within a few days whether there is a significant problem with this one-shot vaccination. If there is, the CDC and the FDA may be able to determine who might be especially susceptible to this unusual kind of blood clot. They could limit the shots to people who would be less likely to get into trouble.
If the adenovirus vaccines are not a problem, shots could resume quickly for most people. In the meantime, the mRNA vaccines appear safe and should continue to be widely available. We are seeing a scary rise in COVID cases. The sooner we can get people protected the better!
