AINsight: Covid-19 Vaccination Updates

 - April 16, 2021, 9:20 AM

This story is part of AIN's continuing coverage of the impact of the coronavirus on aviation.


My plans to write about something other than Covid for this submission were sidetracked by the recent updates to the vaccine situation.  

As you know, the FAA had previously issued approval for pilots to fly (after a 48-hour no-fly wait) after receiving either the Pfizer or Moderna Covid-19 vaccines. Later, once the Johnson & Johnson (J&J) vaccine also received an emergency use authorization (EUA), it too was added to the FAA-approved vaccination protocol. The AstraZeneca vaccine is in use in Europe but has not yet received an EUA for use in the U.S.

This week, the CDC and FDA recommended a “pause” in the use of the J&J vaccine after reports surfaced of rare but serious blood clots in some recipients. These clots have occurred in women between the ages of 18 and 48, and most typically between six and 13 days after vaccination. While rare, less than one case per million doses given, the pause in the use of the vaccine is prudent.

As of the date of this writing, the FAA has not changed any of its guidance for pilots on the use of the J&J vaccine. Likely it is simply waiting for the CDC and FDA to make final rulings, and since the J&J vaccine is not being administered presently, there is no urgent need for the FAA to revise its internal guidance just yet.

Please bear in mind that the mechanism of action of the Pfizer and Moderna vaccines is different than that for the J&J and AstraZeneca vaccines. So far, it appears that the risks for these specific unusual blood clots are not likely with either the Pfizer or Moderna vaccines.

Certainly, nobody wants to be the unlucky person to experience a serious side effect. While we all must make risk/benefit decisions for everything we do in life, if we know of a serious risk we should try to mitigate it before proceeding with the activity. Hence, it is time to determine what the risk actually is with the J&J vaccine. Some blood clots have been noted after vaccinations with the AstraZeneca vaccine too, but again, that vaccine is not in use in the U.S. The pause will allow for several important considerations to be evaluated. 

The first, and most obvious, is the question as to whether the blood clots are indeed caused by the vaccine, or, given how rare the blood clots are being noted, are they simply occurring naturally and by chance in that large of a patient population?

A second consideration—and likely the more important one on a long-term basis should the use of the vaccine continue—is how to best treat these unusual blood clots. They are not forming in manners typical for the types of blood clots we usually see, and therefore they must be treated differently. The pause in the use of the vaccine will give researchers time to determine the best course of treatment so that medical providers will have the knowledge base to treat the blood clots properly in an urgent setting.

Again, the blood clots are forming after less than one in a million doses, but it is prudent to know everything we can about them before resuming the use of the J&J vaccine.

I think it would be surprising if the EUA was withdrawn entirely, and more likely the use of the vaccine will resume in a reasonable period of time. One thought also is whether to simply avoid giving the vaccine to women in the at-risk age groups if and when the use of the vaccine resumes.

People wonder, understandably so, why this potential side effect was not noted during the clinical trials? Most large-scale clinical vaccine trials will have perhaps 30,000 to 40,000 participants, according to Dr. Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases and chief medical advisor to President Biden.

Given that the blood clots are occurring in less than one in a million doses, it is not surprising, therefore, that this “side effect” wasn’t noted in the trials. I put “side effect” in quotations, as we really don’t know yet whether the vaccine itself was causative in the first place.

A pre-publication review of a study from Oxford University in England apparently has determined that regardless of which vaccine a person receives, the risk of dangerous blood clots remains far less than the risk of suffering a blood clot from a Covid infection itself.

You may remember from one of my earlier discussions that a surprising ramification of Covid infections in young people, especially of adolescent age, is blood clots associated with other lingering cardiovascular complications. Therefore, while there may indeed be a small risk of a blood clot after receiving any Covid vaccine, it appears, once again, that the potential ramifications from the disease itself may be worse than the risks from the vaccine. 

Once the study is peer-reviewed and published, hopefully, we can obtain more of the specifics of the results and analysis. Situations do occur where potential side effects of medications or vaccines, or production defects (for mechanical products), are first identified when a product is out in mass use, even after an exhaustive research and development phase did not reveal said problems.

For example, in 1998 the FDA approved sildenafil (Viagra) as the first of the erectile dysfunction (ED) medications. Once it was out in mass use there were reports of an uncommon eye disturbance, Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION), occurring in some men who took Viagra. The question was, of course, was the medication causative, or were the eye problems happening by chance.

The vision impairments secondary to NAION are often permanent, and vision loss in anyone, let alone pilots, is a tragic consequence. You may remember the boilerplate disclaimers on the medication advertisements for all ED medications that state that “If you experience any sudden loss in vision, stop taking the medication…” and call the doctor immediately (not that he/she can do anything about it at that point). To date, there remains no effective treatment for NAION, but research continues.

Those naturally at risk for NAION are those with hypertension, diabetes, and cardiovascular disease—precisely the demographic of the aging men who might benefit from the use of an ED medication. The number of cases of NAION has remained low, and I’m not certain whether true causation was ever attributed to the ED medication or not.

However, a peer-reviewed article I found from 2019 states that, after many additional years of follow-up, the data did not suggest an increased incidence of NAION in men who took sildenafil for ED as compared to by chance alone. Hence, ED medications remain in widespread use. And, for the record, most ED medications are approved by the FAA, with some minor no-fly wait periods after their use.

Regarding mechanical systems, the most famous aviation-related “pause” in the use of an FAA-approved product is the Boeing 737 Max. After the two tragic crashes early on, which occurred after the 737 Max went into worldwide use, the Max was grounded for an extended period of time. Software updates, additional angle of attack sensors, and more education and training for pilots were required before the airplane was finally allowed back into the air. The grounding of the Max may have cost Boeing (and the airlines) billions of dollars, but preventing another tragedy was, without doubt, the primary goal before letting the airplane fly again.

So, the risk/benefit dance of life continues. For the most part, I remain a strong advocate for the efficacy of vaccinations in preventing serious complications of diseases. In my personal risk/benefit considerations, I decided that the potential impacts of a Covid infection on my aging 66-year-old airframe outweighed the risks of receiving the vaccine.

Hence, I chose to receive a vaccine as soon as it was available to me. I also fully respect that some people are choosing to either wait for additional data to come out or may simply avoid receiving the Covid (or any other) vaccination altogether. We all make personal choices, and I respect that each individual has the right to do what he/she feels is best for their personal health.

Further, I support this pause in the use of the J&J vaccine until it can be determined if it is indeed causing the noted blood clots and how to best treat them if they do occur. I will be waiting with interest on the final data that will be published from the Oxford University study noted above.

Most people who fly in airplanes, drive cars, receive vaccinations, take medications, or go scuba diving have no serious complications from doing so. However, it is prudent to be educated and to take appropriate risk-mitigation steps for any activity we choose to engage in. When a patient is going in for surgery, for example, a complicated medicolegal waiver must first be signed, which lists numerous potential complications from the procedure. However, the risk/benefit ratio brought the patient (and the physician) to agree that the surgery is probably that patient’s best option. 

I remain hopeful that, in time, society develops enough of a herd immunity from Covid that a more productive, social, and economically strong lifestyle will return to the world. Sure, the “new normal” is yet to be determined, but I have hope that we are moving in the right direction. 

While the impacts of Covid have been significant and the virus is not going to disappear anytime soon, with appropriate risk mitigation strategies and herd immunity perhaps in the not too distant future we’ll all be flying high once again, smiling, hugging friends and family, and not having to wear face coverings in virtually every social situation. I know I would enjoy seeing people smile, instead of just imagining that they are, hidden below a face mask.

Dr. Robert Sancetta, MD, is a former DC-10 captain with 11,000 flight hours. He has worked as a Senior AME since 1993 and is appointed as AME Consultant to the Federal Air Surgeon.