Data is the lifeblood of naval aviation. Whether you’re a pilot relying on instruments to guide you through bad weather, or a flight test engineer sifting through telemetry to identify that elusive failure mode, your work in the Naval Aviation Enterprise involves interpreting factual evidence accurately in order to make decisions, draw conclusions, and predict outcomes.

The same is true for medicine. During the COVID pandemic, physicians and epidemiologists have been collecting and sharing data about vaccines that enable front-line doctors and nurses to administer them effectively and save lives. One of the tools they rely on to track vaccine side effects is the Vaccine Adverse Event Reporting System (VAERS), a comprehensive database overseen by the U.S. Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA).

If you’ve followed the debate over COVID vaccinations, you’ve probably heard of it. But what does VAERS do, and how should you make sense of the data it collects?

Cmdr. Matthew R. Doubrava, MD, MA, MPH, NAWCAD’s flight surgeon, said that it’s easy to interpret reports of adverse reactions to COVID vaccines as evidence that the vaccines are causing health problems — but jumping to that conclusion without all the facts is a mistake.

“One of the most common misconceptions about VAERS is that if someone reports an adverse reaction, the reaction must have been caused by the vaccine,” said Doubrava, the head of the Aeromedical Monitoring and Analysis branch in NAWCAD’s Human Systems Engineering Department who is board certified in Aerospace Medicine and Occupational Medicine. “What a lot of people don’t realize is that the reports in VAERS haven’t been evaluated by clinicians yet to determine whether there really is a one-to-one correlation there.”

Anyone involved in a clinical trial — the person who received the vaccine, a family member, a caregiver, a healthcare worker, a physician, a person who prescribed the vaccine, even the vaccine’s manufacturer — can input information into VAERS. That information can include reports of fatigue, sore arms, and migraines all the way up to the death of a trial participant. It’s up to clinical researchers to take all of that raw information and analyze it to find meaningful patterns and identify whether the vaccine indeed caused them, or if they were the result of other factors.

In many cases, what looks like causation ends up being coincidence. Doubrava points out that VAERS data has been erroneously used to “prove” adverse reactions to a number of vaccines in the past, including those for measles, mumps, and rubella, the quadrivalent human papillomavirus (HPV4), and polio — vaccines that have since earned excellent track records for safety.

And VAERS data has indeed been instrumental in identifying adverse reactions to the COVID vaccines. “When eight women out of a million doses experienced a highly unusual blood-clotting disorder after receiving the Johnson & Johnson vaccine during clinical trials, the CDC followed up on that and put a warning on that vaccine,” Doubrava said. “The same is true for reports of a heart inflammation called myocarditis in young men following their second dose of an mRNA vaccine. The CDC reported that the side effect occurred in 12.6 cases per million second doses. As a result, they are now advising doctors to be on the lookout for myocarditis cases too.”

In fact, Doubrava points out, the CDC and FDA established the VAERS database in the 1990s in direct response to concerns that vaccines could be causing adverse reactions that doctors and vaccine manufacturers weren’t paying attention to.

“For all the criticism it has received over the years, VAERS still is a highly effective system for finding problems that can arise from the vaccine,” Doubrava said. “And the COVID-19 vaccination is the most watched vaccination in the history of humankind. That’s why we think the vaccine is safer than catching COVID. The risk is small compared to the benefit, which is great.”

As vaccination rates continue to increase, doctors will continue watching the VAERS data closely. And the more vaccinations, the more data they’ll have to draw on. As of mid-October, 94% of active-duty Sailors are fully immunized, while 99% have received at least one vaccine dose. Nearly 5,760,000 total doses have been administered throughout the Department of Defense.

Interpreting data correctly to assess risk is what NAWCAD pros do every day to ensure the aircraft and aircraft systems they test are safe to fly and fight. Taking the same approach to COVID vaccine data, Doubrava said, can be just as effective for saving lives.