Safety of the COVID-19 vaccines

Definitions & Key takeaways

The COVID-19 vaccines have undergone extensive testing in clinical trials involving tens of thousands of participants. Candidate vaccines have to go through both animal trials, and several human clinical trials before they are FDA-approved for distribution. The trials have shown that the vaccines are safe and effective at preventing COVID-19. Common mild side effects of the vaccines include pain and swelling at the injection site, fever, fatigue, and headache. Serious side effects are rare but have been reported in a very small number of people. The benefits of getting vaccinated to protect against COVID-19 outweigh the potential risks of side effects.

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There’s a lot of pressure on researchers and pharmaceutical companies to create a vaccine for COVID-19. You might be wondering, how can we be sure that the vaccine will be safe?
To start, this isn’t the first time we’ve made a vaccine. There are currently over 50 vaccines covering 26 diseases used within the United States alone.
Many of the candidate COVID-19 vaccines being tested right now are based on the ideas and technology used to make vaccines that are already approved.
This is how in the span of just a few months we’ve had so many vaccines enter preclinical and clinical trials. Researchers are not starting from scratch.
In addition, the Food and Drug Administration (also called the FDA) in the United States has given specific guidelines to researchers on how to develop COVID-19 vaccines.
Once we have a candidate vaccine, researchers subject that vaccine to a gauntlet of animal and clinical trial tests, to ensure that it’s both safe and effective.
Researchers initially test candidate vaccines on animals first in preclinical trials, and if testing goes well, the candidate vaccine can begin human clinical trials, starting with Phase I, then Phase II, and finally Phase III.
With each phase, more and more participants are recruited to be vaccinated with the candidate vaccine. Researchers want to test the vaccine in a large and diverse group of people, to make sure that it’s safe and effective for the whole population.
Researchers need to test the candidate vaccine in people who differ in age, sex, race, and exisiting health status, like people who have asthma or are pregnant.
If a candidate vaccine successfully passes Phase III clinical trials, that means researchers are very confident the vaccine will be effective for everyone.
As of October 1st, 2020, there are 10 COVID-19 vaccines currently in Phase III trials, 13 in Phase II, 17 in Phase I, and 151 in preclinical trials.
That’s a lot of vaccines, but that’s on purpose. Researchers expect that some vaccines will not pass all the trials.
Rather than completely betting on one promising vaccine, researchers have many candidates they can fall back on if a leading vaccine doesn’t work out.
If you’ve been watching the news, you can see these checks and balances are at work. For example, in early September 2020 Phase III clinical trials were temporarily halted for the Oxford/AstraZeneca vaccine because an individual who received the candidate vaccine developed spinal cord inflammation.
Researchers are actively investigating if the inflammation was caused by the vaccine, or if it was caused by something else entirely.
It’s possible that the individual had early stage multiple sclerosis that was undetected, and it was a coincidence that symptoms for the disease began to appear near administration of the vaccine.
That said, this would be the second adverse event to occur with this candidate vaccine, with another event occurring back in July.
This is exactly why lots of clinical trials are conducted, and we’ll soon learn the conclusion of both those investigations.
You may have also heard on the news that Russia approved one candidate vaccine for widespread manufacturing and administration.
While the initial results of the clinical trials of this vaccine are promising (like many of the other vaccines in development) Russia chose to skip Phase III trials.
There’s concern amongst the global medical community that insufficient testing might not detect a safety risk and that may be dangerous in the wider population, and so it is unlikely that this particular vaccine will be used outside of Russia.
##Summary As a quick recap, the COVID-19 vaccines currently in development have strong guidelines from the FDA on how researchers should develop the vaccines, and researchers are heavily relying on previous vaccine research and technology to quickly create candidate vaccines.
Candidate vaccines have to go through both animal trials, and three human clinical trials before they are approved for distribution.
Many different vaccines are currently in production, so if one vaccine doesn’t work out, we have more candidates to work on.
By watching trusted news sources, you can keep up to date on the progress, and the delays of each vaccine.