Feature Article: Long-term Side Effects of COVID-19 Vaccine? What We Know.
Published on in Parents PACK
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Published on in Parents PACK
Since COVID-19 vaccines are new, some people have asked about their effects on those who take them. Short-term side effects (i.e., those that happen in the days after a vaccine has been given) are readily apparent because of clinical trial reports and personal experiences, but people also wonder about possible long-term effects of these vaccines. To answer this question, scientists study the available evidence, and while the rules of science do not allow scientists to say that long-term effects can never happen, the evidence is strong that these vaccines will not cause long-term harm.
The history of vaccines shows that severe effects following vaccination can occur. But when they do, these effects tend to happen within two months of vaccination:
These experiences demonstrate two important findings. First, when these events occurred, the onset was within eight weeks of receipt of the vaccine. Second, in all of these cases, except narcolepsy following H1N1 vaccine, the side effect of the vaccine was something that could be caused by the infection, meaning that getting infected with the virus also carried a risk of experiencing these outcomes. In the narcolepsy experience, the cause was determined to be related to the adjuvant used in that preparation of vaccine.
Regardless, this history humbles vaccine scientists. They know that they hold people’s lives in their hands. As stated by Dr. Maurice Hilleman, perhaps the most prolific vaccine scientist in history, “I never breathe a sigh of relief until the first few million doses are out there,” (Personal communication, Paul Offit, 2004). For this reason, scientists and public health officials carefully analyze and continually monitor the data related to every vaccine before, during and after it becomes available.
Even with this history in mind, some reasonably wonder about the COVID-19 vaccines because they have not previously been approved for use in people. Now that millions of doses have been administered, we have learned about a few rare but severe side effects. They all occur shortly after vaccination:
In each of these cases, the side effect occurred within a few days up to a few weeks of vaccination, but all occurred well before two months after vaccination. Likewise, COVID-19 infection also causes myocarditis and GBS and is associated with a variety of blood clotting issues, and the risk of experiencing them is greater following infection than following vaccination.
Some still wonder what might happen months or years after receipt of these vaccines, but we can also be reassured by what we know about how these vaccines are processed:
Because of the knowledge gained with other vaccines, the FDA required companies making COVID-19 vaccines to follow trial participants for a minimum of eight weeks before they could submit their data for approval. Likewise, the participants in the vaccine trials continue to be followed even though the vaccines have been approved for use.
While concerns about long-term effects of vaccines are legitimate, it is important to be aware that the organized anti-vaccine industry has targeted this issue as a way to sow doubt and confusion about COVID-19 vaccines. According to the Center for Countering Digital Hate, professional anti-vaccine activists organized a meeting in the fall of 2020 to create messaging that would decrease acceptance of COVID-19 vaccines once available. These organized efforts aim to move people to extreme positions about vaccines — that is to say, from having legitimate questions about vaccines to becoming “anti-vaccine,” refusing all vaccines and believing conspiracy theories and false narratives. In some cases, individuals in these groups do not believe the science, and in other cases, they are seeking to profit from this hesitancy by encouraging the use of other products to “protect” against COVID-19.
With this in mind, we recommend carefully vetting sources of information, and the statements they are making, to ensure that you are getting answers from reliable sources. Find out more about evaluating information and recognizing false narratives using these tools:
Watch this short video of Dr. Offit discussing, "What Are the Long-term Side Effects of COVID-19 Vaccine?
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Last updated: March 9, 2022
Categories: Parents PACK February 2021, Feature Article
Materials in this section are updated as new information and vaccines become available. The Vaccine Education Center staff regularly reviews materials for accuracy.
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