For some time now I have been raising concerns regarding the safety and efficacy of the Covid vaccine and drug trials. Rushing toward approval—while understandable—can be dangerous. And the recent pause in the Johnson & Johnson and Eli Lilly trials should give all of us pause.

Regarding vaccines:

The Covid vaccines currently most advanced in the US are those of Pfizer and Moderna. People describe taking the vaccines as akin to being kicked by a horse—painful, in some cases dizzying, but transient discomfort. One can’t help but wonder if that will be the end of the story as the vaccine is rolled out to hundreds of millions of people, some of them already in fragile health.

More cause for concern are the reports of at least two cases of transverse myelitis, which caused two pauses in the AstraZeneca vaccine trials. The most recent pause was reversed in some countries but not in the US.

Now comes news of a pause of the Johnson & Johnson vaccine for at least one serious adverse event.

It is unfortunate that the details in both cases are withheld, avowedly to protect the privacy of the affected person. It seems to me that autonomy can be preserved simply without revealing the identity of the person suffering the consequences of volunteering in the trials. We need to know what dangers may attend the use of these vaccines.

It may be relevant that both the AstraZeneca and the Johnson & Johnson vaccine both use the same class of vector, a defanged adenovirus. The specific viral vectors differ slightly as do the components of the SARS-CoV-2 virus they carry. Adenoviruses are known for their ability to infect cells of the nervous system and are for that reason are a favored vector for gene therapy treatments of inherited nervous system disorders. Adverse events such as transverse myelitis may be due to the neurotropic nature of the vector.

It is worth noting that Covid vaccines based on adenovirus vectors are already approved for use in Russia and in China. One of the two vectors used in the Russian vaccine is the same as that used by Johnson & Johnson. We have little to no information regarding the safety and efficacy of either the Chinese or Russian vaccines as they are currently deployed. An accurate accounting of observed adverse events of both vaccines would be very helpful as they are rumored in the press to been given to hundreds of thousands.

Regarding anti-Covid drugs:

The pause of the Eli Lilly monoclonal antibody therapy is especially troublesome as the President of the United States has called for immediate Emergency Use Authorization of the Lilly treatment along with that of Regeneron, well before the trials are complete. It is also concerning that an unproven treatment was given to the highest executive officer in the land, when it and other Covid monoclonal antibodies may have serious safety issues, issues deleterious enough that the FDA has presumably asked Lilly to pause the trial.

The press releases and statements from the companies regarding the pause both emphasize they exercised “an abundance of caution”, and that serious adverse events are common in all large drug and vaccine trials. While this may be true, we deserve to know the details.

The first tenant of medicine is do no harm. We expect and hope that this principle will be upheld despite the urgent need for treatments and vaccines.

Author’s Note: This article was not peer reviewed before publication.