New COVID vaccine warnings in US mean their side effect reporting system is working


Representative photo: Hakan Nural / Unsplash

Although the COVID-19 vaccines currently available in the United States have been shown to be safe and effective, recent reports of rare adverse events or side effects have raised concerns. On July 12, 2021, the Food and Drug Administration approved an update to the Johnson & Johnson COVID-19 vaccine fact sheet to include an increased risk of the rare nerve disease, Guillain-Barré syndrome. This follows previous reports linking the J&J vaccine to a rare blood clot.

While such reports can be frightening, they indicate that the vaccine safety reporting system is working. They also highlight how the relative risks of rare side effects like these need to be put into context.

As a pharmacist who manages the operations of the University of Virginia COVID-19 vaccination program for the past seven months, I have seen how much uncertainty and fear regarding potential side effects can lead to a hesitation about vaccination. Understanding how information about adverse events is collected and what this means for vaccine safety can help people make informed decisions about their health.

Safety monitoring before, during and after approval

The FDA has rigorous testing and approval processes that manufacturers must follow before a new vaccine can be made available to the public. Whether a vaccine is approved through the typical FDA approval process or Emergency Use Authorization (EUA), the steps required to test a new drug for safety and efficacy are the same. An EUA can deliver a vaccine to the public faster by streamlining the regulatory process, but no shortcuts are taken. All steps are taken to ensure that the vaccine is both safe and effective.

Clinical vaccine trials take place in four sequential phases. In the first three phases, study researchers are the ones who identify, quantify, and document security issues. Phase 1 typically introduces the vaccine to fewer than 100 people over several months under controlled conditions. Typically, the majority of potential adverse events are identified at this stage.

After the FDA reviews the data from Phase 1 and found the vaccine safe enough for further study, the vaccine moves to Phases 2 and 3, where it will be given to more people over longer periods of time. . Here, investigators determine the optimal dosage and screen for rare side effects.

If the data from phases 2 and 3 meet FDA approval standards, then the vaccine will move to phase 4 and become available to the public. The vaccine is seen in much larger populations and over extended periods of time, and manufacturers are required to regularly check and report potential safety issues to the FDA.

What is different in this final phase is that the public can also contribute to the safety reports. The Vaccine Adverse Event Reporting System (VAERS) is a national safety oversight system administered by the FDA and the Centers for Disease Control and Prevention. Although some types of adverse events, such as injury during vaccine administration and serious complications, are mandatory for health care providers, anyone can submit a report. Recent adverse events associated with the COVID-19 vaccine, including Guillain-Barré and thrombosis for Johnson & Johnson and myocarditis for Pfizer, were identified via VAERS.

The risk of a serious vaccine-related adverse event is low

A rare adverse event can take months or years to be identified for one simple reason: it is rare. For some drugs that are less commonly used, new safety data takes longer to discover because a relatively small number of patients are using the drug. For example, although the Shingrix shingles vaccine was approved in 2017, it wasn’t until March 2021, after more than 3.7 million patients had been vaccinated, that the FDA announced a potential increased risk. by Guillain-Barré. And it has still not been confirmed that the Shingrix vaccine causes the nerve disease.

For cases like the COVID-19 vaccine, however, millions of people will receive the drug soon after it is released to the public, and new problems or patterns often emerge more quickly.

This can lead to two problems.

First, not all reported adverse events are directly related to the vaccine. For example, many of the tens of millions of people who have received the Pfizer vaccine have likely suffered sunburn. People can report sunburn to VAERS, but the vaccine has no effect on your skin’s ability to protect itself from the sun. The VAERS is very clear that it “is not designed to determine whether a vaccine has caused a health problem, but that it is particularly useful for detecting unusual or unexpected patterns of adverse event reporting.” . Correlation does not mean causation.

Second, a plausibly identified adverse event does not necessarily make the vaccine unsafe. According to the CDC, there have been 100 preliminary reports by Guillain-Barré of 12.5 million doses of J&J, or 0.0008% of people who received the vaccine. Giving a vaccine to a large sample of people can make it easier to identify a possible link between the vaccine and a side effect. But that doesn’t mean that the risk of having this side effect is very likely, or that it outweighs the benefit of getting the vaccine.

These risks, while real and potentially fatal, must be seen in the context of the much greater risk of negative consequences from the diseases that vaccines protect people from. For example, 1 to 7% of patients who take cholesterol medications called statins are at risk for potentially dangerous muscle damage. However, these drugs are still taken by millions of people because they are very effective in preventing heart disease and stroke. And in Guillain-Barré’s case, about one in 100,000 people, or 0.001%, develop this disease each year in the United States, regardless of the cause. By comparison, the United States has recorded more than 33 million cases of COVID-19 and more than 600,000 deaths from the disease.

COVID-19 greater risk than vaccine side effects

At times as extraordinary as during a pandemic, it’s understandable that people are reluctant to take more risks than they have to. But safety nets are in place to monitor COVID-19 vaccines, and they still work as they should.

COVID-19 vaccines have been shown to be extremely safe for most people. More than 40,000 patients participated in J & J’s clinical trials before the company applied for emergency use authorization, reflecting the sample sizes of the Pfizer and Moderna studies. About 0.4% of J&J trial participants experienced serious adverse events unrelated to COVID-19 infection. In contrast, the trial showed that people who get vaccinated are 85% less likely to contract severe COVID-19 than those who are not vaccinated.

The extremely rare side effects associated with COVID-19 vaccines were discovered because the safety reporting tools were used appropriately. Being aware of the risks of treatment, however rare, can help people make the health decisions that are best for them. However, these risks must be placed in context. And in the case of COVID-19 vaccines, they must be weighed against the consequences of staying unvaccinated and letting the pandemic rage.

Justin Vesser is director of outpatient pharmacy services at the University of Virginia.

This article was originally published by The conversation and has been republished here under a Creative Commons license.


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