For many, COVID-19 vaccines have a number of side effects


Getting a COVID-19 vaccine has many benefits. There is the protection against a world-changing virus, the ability to travel more safely and hang out in people’s homes again. There are also donutsBut there is also a good chance that a vaccine is associated with some unwanted side effects. Most of these are quite benign, such as an aching arm or fatigue. Some are more serious, but they are also extremely rare.

Here’s a cheat sheet to help you figure out what to expect after your COVID-19 shot.

What Are Some Common Side Effects?

Your arm may feel painful after you receive the injection, and there may be some redness or swelling near the injection site. There is also a chance that you will get a headache, fever, muscle aches, chills, tiredness or nausea.

This is all according to the Centers for Disease Control and Prevention (CDC) that has a useful page about side effects.

What if I notice something else that isn’t on that list?

The CDC’s list includes the most common side effects – there may be others that are less common or that haven’t turned up in studies yet. Researchers are still collecting data on vaccines and their side effects. In fact, a brand new study is looking for a possible link between vaccines and irregular menstrual cycles.

As with any medical treatment, watch your symptoms and see your doctor if you have any concerns.

If you’re in the US and you want to help researchers collect data on vaccine side effects, you can also enroll in the CDC’s v-safe program as soon as you get your chance. It’s a smartphone-based system that ask about your side effects after you have been vaccinated.

I heard it’s the second shot you get – is that true?

Yes, if you are receiving a two-dose vaccine such as Pfizer or Moderna, your symptoms may be more intense after your second injection than after your first injection. It’s not necessarily a bad thing – it means your body has learned its lesson from the first dose and your immune system is now ready to fight the coronavirus that causes COVID-19.

“Your body is prepped by that first dose of vaccine.” said Melanie Swift, co-chair of the COVID-19 Vaccine Allocation and Distribution Work Group at Mayo Clinic in a Q&A“The second dose of vaccine enters your body, starts making that peak protein, and your antibodies jump on it and amplify the response of your immune system. It’s as if they studied for the test. And it passes the test. “

A person will receive their first injection of a COVID-19 vaccine in Los Angeles on April 9.
Photo by Mario Tama / Getty Images

Who is more likely to have side effects?

Younger people are more likely to have side effects. The immune system gradually weakens as you get older, this is called immunosesescence. Younger people’s immune systems are more likely to respond strongly to a vaccine, making them more likely to feel side effects if their bodies go through exercise to fight an infection.

Women are also more likely to report side effects after receiving an injection. Many women generally have a stronger immune response to vaccines, and the COVID-19 vaccines are no different. But other factors, including gender bias in study design and inconsistent reporting can also play a role

I know I’m going to be sore – do I have to take anything beforehand?

No. “It is not recommended to take over-the-counter medications – such as ibuprofen, aspirin, or acetaminophen – before vaccination to try to avoid vaccine-related side effects.” the CDCs page on preparing for your COVID-19 vaccination says. Researchers are not sure if those drugs can change the way the vaccines work, so they ask people to wait and not take those painkillers or antihistamines before your appointment.

After your appointment is a different story. While the CDC still recommends that you speak with your doctor before deciding to take any medications, it also says that you can take over-the-counter medicines ‘to relieve the side effects after vaccination if you have no other medical reasons that prevent you from taking these medicines normally’.

If you’re in pain after your injection, the CDC recommends putting a cool washcloth over the area and moving your arm around.

Are some vaccines more likely to have side effects than others?

Looking forward to it. A study published this week found that people who received Moderna’s vaccine were more likely to say they had side effects than people who received the Pfizer / BioNTech shot.

Both vaccines are still considered safe and effective.

California agricultural workers receive COVID-19 vaccination

People wait in a medical observation room after receiving their injection.
Photo by Mario Tama / Getty Images

What about the rare, scary side effects?

There have been a few instances where people had a severe allergic reaction to their injections – severe enough that they had to take epinephrine or go to a hospital. That’s one of the reasons people are asked to hang out for medical observation for about 15 minutes after getting their vaccine.

Other people may have what is still considered an ‘immediate’ allergic reaction (hives, wheezing, swelling) within four hours of their injection. In those rare cases, or if you are allergic to anything in the shotsdoctors may advise you to get a different vaccine.

Outside of the US, some researchers have noticed that in very rare cases, some people who receive AstraZeneca’s COVID-19 vaccine develop serious blood clots. This may be due to an unusual antibody response, but it is still not sure what is causing the clots, or who is most at risk, although it is seems to be safer in older peopleThis particular vaccine is not approved for use in the US.

When should I be concerned about side effects?

The CDC recommends that you speak with a doctor if your side effects don’t go away after a few days, or if you start to worry.

If I don’t have any side effects, does that mean it isn’t working?

While it’s true that side effects are a sign that your body is building up its COVID-19 defenses, that doesn’t mean the vaccine won’t work if you don’t have them. You are still protected, you just happen to be one of the lucky people whose immune system doesn’t totally hurt you.

Here’s what else happened this week.

Antivirus is taking a break next week, April 17. We are back on April 24th.


What are we waiting for?
This week my colleague Monica Chin asked a host of experts what kind of measures we were looking for to resume activities such as travel, theater and other things that were considered high risk in the past year. It is well worth reading. (Monica Chin /The edge

Has the era of overly diligent cleaning finally come to an end?
This week, the CDC updated its cleaning guidelines, highlighting that the odds of catching the virus from a surface are only 1 in 10,000. That’s a big change from earlier in the pandemic, when we were all washing everything that got into our homes. Cleaning is still important – especially around someone with an active infection, but many experts now believe the greater risk of transmission is airborne. (Emily Anthes /The New York Times


Researchers are hatching a cheap coronavirus vaccine
Some scientists are starting to test a cheap vaccine that is easier to make than alternatives. If it works, it can make a big difference in the push for global vaccination. (Carl Zimmer /The New York Times)

Scientists are working on an elusive dream: a simple pill to treat Covid-19
Antivirals are incredibly difficult to develop, but some researchers are still hoping to find “a Tamiflu for SARS-CoV-2”. It’s a very complicated mission that is definitely easier said than done. (Damien Garde /STAT)


She grew up in Hungary, the daughter of a butcher. She decided she wanted to become a scientist, although she had never met one. She moved to the United States in her twenties but never found a steady job for decades, clinging to the fringes of academia.

– In a moving profile for The New York Timesjournalist Gina Kolata describes the extraordinary life of Katalin Kariko, an mRNA researcher whose work has been critical to the current push to develop COVID-19 vaccines.

More than numbers

To the people who use it 748 million vaccine doses spread so far – thank you.

To the more than 134,719,328 people worldwide who have tested positive, may your path to recovery go smoothly.

The families and friends of the 2,915,972 people who have died worldwide – 561,074 of those in the US – are not forgotten about your loved ones.

Stay safe, everyone.