COVID-19 vaccine side effects: what to expect + tips for care

Digital generated image of COVID-19 vaccine bottle standing on multi coloured circles on purple background.

Every day we make choices on what we put into or onto our bodies – often without much thought of how we’ll feel afterwards. But when it comes to taking a medication or getting a shot like one of the available COVID-19 vaccines, we want to know what to expect right after getting one – and long-term.

In fact, nearly 38% of people polled on BlueCross BlueShield of Tennessee social channels were most interested in learning about COVID-19 vaccine side effects.

And now that more than 150 million people in the U.S. have been vaccinated – under the most intense safety monitoring in our history, here’s what you need to know.

Common, short-term side effects happen soon after vaccination

More often than not, many people simply experience a mild immune response (short-term side effects), if anything at all. These side effects are normal – a sign your immune system is working to build protection against the germ – and should go away in a couple days, if not sooner:

  1. At the injection site: soreness or pain, redness, swelling, or
  2. Throughout the rest of your body: tiredness or fatigue, headache, muscle pain or aches, chills, fever or nausea.

Tips for care:

  1. Try an ice pack after your injection to ease any inflammation and light movement of your arm to alleviate soreness.
  2. Practice good health-promoting behaviors like: getting plenty of sleep, drinking water and eating healthy foods along with avoiding excessive drinking.
  3. Talk to your doctor about over-the-counter medications for any discomfort and be sure to update them if your side effects don’t seem to go away after a few days.

Bottom line: Side effects are normal, but not everyone will experience them – and some could experience them more intensely, especially after the second dose of a Pfizer or Moderna vaccine. So, don’t hesitate too much, but it’s okay to plan your vaccination on a day you can take it easy and relax afterwards.

After COVID-19 vaccination, register for V-safe so you can report any side effects you experience.

Rare allergic reactions happen within hours of vaccination

The CDC reports that a severe allergic reaction (anaphylaxis) after COVID-19 vaccination is rare and has occurred in around 2 to 5 people per 1 million vaccinated in the U.S.

  1. A severe allergic reaction requires treatment with epinephrine (or EpiPen) and almost always occurs within 30 minutes after vaccination – anaphylaxis includes a drop in blood pressure, a rapid but weak pulse, skin rash and nausea and vomiting.
  2. An immediate, non-severe allergic reaction doesn’t require epinephrine (or EpiPen) and happens within 4 hours of getting vaccinated and can include: hives, swelling, wheezing (respiratory distress).

Bottom line: Allergic reactions are extremely rare but can happen, so be sure stay at your vaccination site for the recommended amount of time so you can be monitored for a reaction in a safe environment. If you do have an allergic reaction, talk to your doctor or pharmacist first before moving forward with follow-up doses.

What the history of vaccines taught us about long-term effects

Even though there’s strong medical evidence that the benefits of vaccines far outweigh the risks, it’s understandable to have concerns about possible negative effects. Any treatment, medication – or a disease itself, can cause long-term effects.

But when it comes to vaccines, their history has provided evidence that informed experts on long-term effects and when to expect them. Delayed effects from vaccines have been rare, but they have occurred in the past.

When delayed effects did occur, they happened within 8 weeks of vaccination:

  • During the H1N1 pandemic in 2009, one influenza vaccine in Finland had an adjuvant (ingredient) that caused narcolepsy in about 1 in 55,000.
  • A swine influenza vaccine in 1976 was a rare cause of Guillain-Barré Syndrome, which is also a 17 times more frequent side effect from natural infection than vaccination.
  • A few other traditional vaccines – polio, MMR, yellow fever also had rare occurrences of causing delayed symptoms like ones caused by getting infected naturally by the germs.

Bottom line: There hasn’t been a vaccine in history that has seen a delayed effect happen after 8 weeks of vaccination. The very nature of how vaccines work and how our immune system builds protection by using them suggests they don’t remain in our bodies for a long period of time.

What that meant for COVID-19 vaccine development and testing

While it’s normal to have concerns about long-term effects of vaccines, it’s important to understand experts have applied knowledge learned from the history of vaccines to today’s COVID-19 vaccines:

  • The Food and Drug Administration (FDA) required a minimum of 8 weeks of monitoring the tens of thousands of volunteers after full COVID-19 vaccination during clinical trials.
  • This 8-week time frame allowed them to have a good understanding of short-term and potentially delayed side effects from these vaccines.
  • These same tens of thousands of clinical trial participants will continue to be monitored even after vaccines are authorized for use.

Bottom line: All authorized COVID-19 vaccines have been held to the same rigorous safety and effectiveness standards as other vaccines. Even after millions of people in the U.S. and around the world have been vaccinated the past several months, results continue to be positive.

There’s no evidence that COVID-19 vaccination has contributed to death

While severe allergic reaction (anaphylaxis) can lead to death if left untreated, there is no evidence that COVID-19 vaccination has contributed to deaths among those vaccinated. Here’s what we know right now:

  • More than 150 million doses of COVID-19 vaccines have been given in the U.S. since December 2020.
  • During this time, the Vaccine Adverse Event Reporting System (VAERS) received less than 2,000 reports (0.0018%) of death among people who have been vaccinated.
  • Medical experts reviewed clinical information including death certificates, autopsy, and medical records of these VAERS reported deaths and these extensive reviews revealed no evidence that vaccination contributed to these deaths. 

Bottom line: These vaccines are undergoing the most intensive safety monitoring in our history and results from these efforts have been reassuring. With more than 500,000 COVID-19 infection deaths in the U.S., among nearly 30 million infected people, these vaccines are our best hope to save lives and return to normalcy as soon as possible.

Need more advice?

First, get to know exactly how vaccines work and what to expect when you get one. If you have questions or concerns about vaccines based on your health status, speak to a provider who knows your medical history. Your friends and family may have good intentions, but they may not know your body like you and your doctor, so it’s important to speak to a provider who knows you well.

If you do decide to go online to learn more about vaccines, do seek reputable sources like the CDCFDA or World Health Organization (WHO). You can also visit to get the latest facts on and support for COVID-19 and vaccines, along with information on how BlueCross BlueShield of Tennessee is supporting its members and communities through the COVID-19 pandemic. 

More COVID-19 vaccine stories from WellTuned


Suzanne Corrington, M.D.

Dr. Corrington serves as medical director of care management services for BlueCross BlueShield of Tennessee where she directs teams and programs related to medical management and quality care initiatives. Before joining BlueCross in 2016, Dr. Corrington worked in emergency medicine, internal medicine for a private practice, and in clinic and hospital services.

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Filed under: Health Topics, Mind & Body


Dr. Corrington serves as medical director of care management services for BlueCross BlueShield of Tennessee where she directs teams and programs related to medical management and quality care initiatives. Before joining BlueCross in 2016, Dr. Corrington worked in emergency medicine, internal medicine for a private practice, and in clinic and hospital services.