VaxFacts Side Effects

What are the most common side effects of COVID-19 vaccination?
Our bodies' immune system produce a variety of mild symptoms when introduced to a vaccine. It's a sign our body is producing antibodies to fight the virus. These symptoms are often extremely mild and can include: Sore arm, swollen lymph nodes, chills or fever fatigue, body aches, or feeling run down, joint pain, headache, nausea, vomiting or diarrhea. These symptoms normally resolve within 1-2 days.

Will I miss work because of my side effects?
Everyone is affected differently. While there are a set of common side effects, some individuals can be hit harder than others. The vaccine does not introduce the COVID-19 virus into your body, so you are not infectious even if you feel sick. Your employer should accommodate you during this short period of time.

Even with the vaccine, I can still get COVID, so what's the point?
No vaccine is 100% effective, but this does not mean you are not protected. Clinical trials showed that new mRNA COVID-19 vaccines are 90%+ effective at preventing symptomatic infection [5]. Breakthrough infections are to be expected and many of these breakthrough cases are from variants like Delta. The small minority of people who become infected with COVID-10 after vaccination and develop symptoms are infectious for a smaller duration of time and have lower viral levels in their bodies, reducing transmission, while also reducing risk of hospitalization and death [6,7]. Vaccines provide the necessary protection for both your own personal health, but also reduces the community transmission that allows for the virus to mutate and the pandemic to continue.

What side effects from the COVID-19 vaccine are considered normal or expected?
Most people will experience mild short-term side effects, such as pain at the injection site. Vaccines, the COVID-19 vaccine in particular, activate the immune system which then gets to work on creating a blueprint on how to fight and protect the body against infection. While the body is creating this plan, our immune system believes it is fighting an actual virus and this can cause side effects like fever, chills, muscle pain, etc. This is completely normal and may last a day or two [1].

How do we know the COVID-19 vaccine won't have long-term side effects?
History! Billions of people throughout time have been vaccinated and while extremely rare side effects can happen with any vaccine, nearly all these side effects can also occur more seriously through normal infection of a virus. Records show that side effects, if any, occur within 2 months of vaccination [2]. They do not develop years after they are used. mRNA, which is the technology used in the Pfizer and Moderna vaccines, degrades in the body naturally after a few days, and the spike protein it creates only stays for a couple weeks [3]. If a severe side effect were to occur, like myocarditis, it would be during that time [6]. Only the anti-bodies your body creates to fight the disease are left behind.

Should I be worried about other adverse side effects being reported?
No! As it stands, millions of people have been vaccinated already, and Moderna (18 and older) and Pfizer/BioNTech (16 and older) vaccine have even received full FDA approval. Adverse events can be reported to the Vaccine Adverse Event Reporting System (VAERS), an early warning system designed to provide surveillance of safety concerns related to vaccination. While it’s very useful in finding safety signals and finding hypotheses, it’s a passive surveillance system. This means anyone can report a case here and it’s not verified. In multiple places on the VAERS website you can find warnings like: “The reports may contain information that is incomplete, inaccurate, coincidental, or unverifiable” or “The inclusion of events in VAERS data does not imply causality”. VAERS is not comprehensive and certainly not rigorous enough to make sweeping statements about the safety of vaccines [4].

COVID-19 infections, on the other hand, do come with a risk of long-term side effects...
COVID-19 has documented long term side effects and while vaccines do not have prolonged side effects, this virus does. This is known as post-COVID-19 syndrome, or "long COVID-19." The virus infects and damages not only the lungs but also the heart, brain and various other bodily systems leading to a variety of long-term side effects [5]. A recent study estimates that 1 in 8 people develop Long COVID after a COVID-19 infection [7].