PAUSED: Updates on the J&J vaccine
Answering some of the most important questions (that can be answered today)
Early this morning, the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) recommended in a joint statement a PAUSE in the use of the Johnson & Johnson COVID-19 vaccine. The decision to pause the distribution and use of the vaccine was made out of “an abundance of caution” following reports of rare but severe side effects among individuals who received the vaccine. During this pause, safety data will be reviewed and healthcare providers around the country will be alerted about this rare, but serious side effect and how to treat it.
Why pause now?
As of yesterday (April 12), more than 6.85 million doses of the J&J vaccine have been administered in the US. Among those 6.85 million doses, SIX cases of a rare and severe type of blood clot (associated with low platelet levels) were reported among individuals who were vaccinated before experiencing the blood clot. All six of these cases were women between the ages of 18-48 years. One of the women has died and another is currently hospitalized. According to the joint statement, a “safety signal” has been triggered and an investigation of the cluster of cases is warranted.
What does this mean if you have received the J&J vaccine?
If you received a J&J vaccination, DO NOT PANIC. This side effect is rare (1 in a million), and it appears to occur within three weeks after vaccination. However, look out for symptoms associated with these blood clots, including severe headaches, abdominal pain, leg pain, or shortness of breath. If you experience any of these symptoms, contact your healthcare provider immediately.
What is going on? Does the J&J vaccine CAUSE these blood clots?
This is the million-dollar question.
Medical and public health researchers have not yet determined if the vaccine is responsible for these blood clots developing. The current hypothesis is that these blood clots — known as cerebral venous sinus thrombosis — could result from the vaccine activating the immune system (more below). It is really important to note that a cause-effect relationship between the vaccine and these blood clots has not been established yet. The pause in the vaccine distribution is designed to allow researchers to answer these questions and put all the clues together to determine what is happening.
These blood clots do occur without vaccines. This means it is possible that individuals who developed these clots after being vaccinated could have developed them had they not been vaccinated.
If only we had a time machine and could go back in time to see what would happen if they were not vaccinated!
Without a time machine, researchers will have to try and determine the normal rate of these clots and compare that rate to what is seen among individuals who have received the J&J vaccination.
What about the Pfizer & Moderna vaccines?
More than 97 million doses of the Pfizer vaccine and 84 million doses of Moderna have been administered in the United States. To date, there have been ZERO reports of blood clots associated with either of these vaccines.
Is this happening because the vaccine development was rushed?
No. This rare, but severe side effect appears to be connected to the technology J&J used in the development of their vaccine. The J&J vaccine uses an adenovirus (or a virus vector) to transport the SARS-CoV-2 DNA into an individual. J&J and AstraZeneca use the same technology and both vaccines have been linked to these blood clots. According to Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia and member of the ACIP, predicts —
“There is going to be something about the adenovirus — whether it’s adenoviral DNA or an adenovirus protein — that complexes with platelet factor 4 (causing these rare blood clots). So that will be determined, I suspect soon.”
Also, J&J noted the risk of “embolic and thrombolytic events” in the results of their Phase III clinical trial. There were 15 events in the group that received the vaccine and 10 among individuals in the placebo group during the trial.
J&J reported (here on pg 7) —
“Data at this time are insufficient to determine a causal relationship between these events and the vaccine. There were no other notable patterns or numerical imbalances in the available data as of the cutoff date between treatment groups for specific categories of adverse events that would suggest a causal relationship to Ad26.COV2.S (aka the J&J vaccine).”
What happens next?
CDC’s Advisory Committee on Immunization Practices (ACIP) will meet tomorrow (Wednesday, April 14) at 2:30 ET to review these cases and assess their potential significance. I am imagining the ACIP will be discussing (1) the potential mechanisms by which these blood clots could be caused by the vaccine, (2) any potential similarities among the six women who experienced one of the blood clots, and (3) whether the risk of blood clots potentially associated with the J&J vaccine outweighs the benefits of the COVID vaccine.
I will provide updates following the meeting(s).