health

What COVID-19 vaccine side effects might you expect?

27 Comments
By Matthew Woodruff

A frequently asked question is what COVID-19 vaccine side effects a person might expect.

You might experience redness and soreness in the arm where you got the shot, tiredness, muscle aches, chills and nausea, but these symptoms won’t last long.

You will be monitored for 15-30 minutes after you get your shot for more serious side effects, which are rare.

Side effects do not mean that you have contracted COVID-19. Vaccines work by training your immune system to recognize and remember a pathogen in a safe way.

Talk to your doctor about over-the-counter pain relievers in case you do experience flu-like symptoms after the shot, but do not take pain relievers before you get the shot.

If you have not received your COVID-19 vaccination yet, chances are that your number is coming up soon. What can you expect when you get your shot? It’s not a day at the park for many, but others feel nothing. It’s impossible for experts to predict who’s going to feel fine and who’s not. In the vast majority of cases, any side effect you feel will be over within a few days, and there is no reason for concern.

But it is important that the medical and scientific communities talk about the temporary side effects from these vaccines – and that the public know that there is a very small percentage of adverse reactions.

I am an immunologist who studies the fundamentals of immune responses to vaccination, so part of that responsibility falls on me.

Receiving these vaccines will likely make a lot of people feel crappy for a few days. That’s a far better prospect than long-term illness or death. In case you may wonder why it makes anyone feel bad at all, I’ll explain.

Immunology’s ‘dirty little secret’

In 1989, immunologist Charles Janeway published an article summarizing the state of the field of immunology. Until that point, immunologists had proposed that immune responses were initiated when the immune system encountered anything foreign – bacteria, viruses, and parasites – that it determined to be “non-self.”

Janeway suspected that there was more to the story and famously laid out what he referred to as “the immunologist’s dirty little secret”: Your immune system doesn’t respond just to all foreign things. It responds to foreign things that it perceives to be dangerous.

Now, 30 years later, immunologists know that your immune system uses a complex set of sensors to understand not only whether or not something is foreign, but also what kind of threat, if any, a microbe might pose. It can tell the difference between viruses – like SARS-CoV-2 – and parasites, like tapeworms, and activate specialized arms of your immune system to deal with those specific threats accordingly. It can even monitor the level of tissue damage caused by an invader and ramp up your immune response to match.

Sensing the type of threat posed by a microbe, and the level of intensity of that threat, allows your immune system to select the right set of responses, wield them precisely, and avoid the very real danger of immune overreaction.

Vaccine adjuvants bring the danger we need

Vaccines work by introducing a safe version of a pathogen to a patient’s immune system. Your immune system remembers its past encounters and responds more efficiently if it sees the same pathogen again. However, it generates memory only if the vaccine packs enough danger signals to kick off a solid immune response.

As a result, your immune system’s need to sense danger before responding is at once extremely important and highly problematic. The requirement for danger means that your immune system is programmed not to respond unless a clear threat is identified. It also means that if I’m developing a vaccine, I have to convince your immune system that the vaccine itself is a threat worth taking seriously.

Scientists can accomplish this in a number of ways. One is to inject a weakened – what immunologists call attenuated – or even killed version of a pathogen. This approach has the benefit of presenting a pathogen almost identical to the “real” pathogen, triggering many of the same danger signals and often resulting in strong long-term immunity, as is seen in polio vaccination. It can also be risky – if you haven’t weakened the pathogen enough and roll out the vaccine too fast, there is a possibility of unintentionally infecting a large number of vaccine recipients.

A safer approach is to use individual components of the pathogen, harmless by themselves but capable of training your immune system to recognize the real thing. However, these pieces of the pathogen don’t often contain the danger signals necessary to stimulate a strong memory response. As a result, they need to be supplemented with synthetic danger signals, which immunologists refer to as “adjuvants.”

Adjuvants are safe, but designed to inflame

To make vaccines more effective, entire labs have been dedicated to the testing and development of new adjuvants. All are designed with the same basic purpose – to kick the immune system into action in a way that maximizes the effectiveness and longevity of the response.

To do this, we take advantage of the same sensors that your immune system uses to sense damage in an active infection. That means that while they will stimulate an effective immune response, they will do so by producing temporary inflammatory effects.

At a cellular level, the vaccine triggers inflammation at the injection site. Blood vessels in the area become a little more “leaky” to help recruit immune cells into the muscle tissue, causing the area to become red and swell. All of this kicks off a full-blown immune response in a lymph node somewhere nearby that will play out over the course of weeks.

In terms of symptoms, this can result in redness and swelling at the injection site, stiffness and soreness in the muscle, tenderness and swelling of the local lymph nodes and, if the vaccine is potent enough, even fever (and that associated generally crappy feeling).

This is the balance of vaccine design – maximizing protection and benefits while minimizing the uncomfortable, but necessary, side effects. That’s not to say that serious side effects don’t occur – they do – but they are exceedingly rare. Two of the most discussed serious side effects, anaphalaxis (a severe allergic reaction) and Guillain-Barré Syndrome (nerve damage due to inflammation), occur at a frequency of less than 1 in 500,000 doses.

Vaccination against SARS-CoV-2

Early data suggest that the Moderna and Pfizer mRNA vaccines against SARS-CoV-2 are highly effective – upwards of 90%. The Johnson & Johnson vaccine is also highly effective, although it was not developed using mRNA technology. All three are capable of stimulating robust immune responses, complete with sufficient danger signaling, to prevent severe COVID-19 in greater than 9 out of 10 patients. That’s a high number under any circumstances, and suggests that these vaccines are potent.

In an early release of the phase 3 trial data, more than 2% of the Moderna vaccine recipients experienced what they categorized as severe temporary side effects, such as fatigue and headache. However, more mild side effects are common – particularly after the second dose. These are signs that the vaccine is doing what it was designed to do – train your immune system to respond against something it might otherwise ignore so that you’ll be protected later. It does not mean that the vaccine gave you COVID-19.

It all comes down to this: By getting vaccinated, you protect yourself, your loved ones and your community from a highly transmissible and deadly disease. It may cost you a few days of feeling sick.

Matthew Woodruff is an instructor at the Lowance Center for Human Immunology at Emory University in Atlanta, Georgia.

The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.

© The Conversation

©2021 GPlusMedia Inc.

27 Comments
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I hope this article is widely read, not just the headline.

7 ( +7 / -0 )

I am a staunch believer in these vaccines and the science behind them. However, I do have my reservations about one of the vaccines. The Astra Zeneca vaccine and the issues with clotting that has led to deaths. It appears that there is a correlation between this vaccine and deaths related to clotting.

https://www.wsj.com/articles/scientists-say-they-found-cause-of-blood-clotting-linked-to-astrazeneca-vaccine-11616169108

Although there is a treatment for it. I am weary of being given this particular vaccine and then being in a situation where I might not be able to obtain timely treatment. I know the possibility is low, but I will not allow myself or my family to get this vaccine. I hope Japan takes steps to think about whether or not to approve this vaccines for those in Japan. Even in America, Dr. Anthony Fauci is now saying that America may not need the AZ vaccine.

My area will hopefully receive either the Pfizer or Moderna vaccines for myself and my family. If not, I will wait or go to the area where I can receive it. I know there is a chance of anaphylaxis, but the vast, vast majority of those cases appear within 30 minutes of receiving the vaccine while you are waiting in the hospital, where treatment is available.

1 ( +3 / -2 )

I hope this article is widely read, not just the headline.

Unfortunately it is too predictable the usual comments will appear, trying to mislead people into thinking the vaccines don't prevent infections, complications or death (they do) or that they don't even reduce transmission (also proved by now). Some may even come to contradict the whole article by exaggerating the risks of side-effects and present incomplete information (like the usual VAERS numbers) to make it seems important negative effects only happen to people that are vaccinated, carefully hiding that those important negative effects happen at about the same rates in unvaccinated people.

At least antivaxxers can't use the fake argument that vaccines are supposedly promoted as 100% safe and without side-effects, the article would prove them wrong immediately.

4 ( +10 / -6 )

Also, I wonder if not mentioning the AZ vaccine and its potentially deadly side effects was intentional or not.

-1 ( +4 / -5 )

And a second by the way, I ran into two Air Force service members on Saturday here in Iwate. In our brief conversation I asked how are things on the base regarding COVID-19 and vaccinations. They said that they had both received the Moderna vaccine and things on the base are becoming more relaxed. That has me wishing that I was still in the Air Force.

-1 ( +2 / -3 )

First dose (Moderna), really bad pain in the shoulder injection area that was far more painful and longer lasting than previous flu shots. Lasted two and a half days.

Second dose, initial pain in shoulder injection area but not as severe as first time. Felt a little light headed but after four hours felt fine. Then 16 hours later it hit, body aches all over, slightly feverish, felt out of it like the flu. Not as bad as the worst flu I have ever had, but still enough to put me out of action for a day. Then it quickly went away after a day.

Everyone else that I knew that had the same Moderna injections also had similar experiences on the second dose, though their symptoms seemed worse than mine's. I have read that those who get really sick after first shot may have been exposed to COVID-19 previously.

3 ( +4 / -1 )

I trust the data the doctors are using rather than newspapers:

https://www.bmj.com/content/372/bmj.n393/rr-4?s=08

-3 ( +3 / -6 )

In light of the risks of either receiving or not receiving the vaccine, let every person make their own decision without judgement from others.

-2 ( +6 / -8 )

At least antivaxxers can't use the fake argument that vaccines are supposedly promoted as 100% safe and without side-effects, the article would prove them wrong immediately.

Indeed, the "antivaxxers" no longer say that because the vaccine promoters had to stop saying they were 100% safe, with all the vaccine-induced side effects and deaths.

-7 ( +4 / -11 )

At least antivaxxers can't use the fake argument that vaccines are supposedly promoted as 100% safe and without side-effects, the article would prove them wrong immediately.

The article also proves what concerned people have been saying all along, that vaccine injury is real and are a recognized risk. Thus, where there is risk there must be choice without judgement or negative consequences.

-3 ( +5 / -8 )

In light of the risks of either receiving or not receiving the vaccine, let every person make their own decision without judgement from others.

The risks of receiving the vaccine are extremely low for the vast majority of the population, as even this article points out, especially comparative to the risks of covid itself. Unless you consider headaches a crippling side effect.

The reason people shouldn't just make a choice for themselves is it is a public health concern, not a personal choice. Someone who, for legitimate medical reasons, cannot receive the vaccine is put at risk by every person who chooses not to take it because they read a facebook post telling them not to. You are risking more than yourself by not getting vaccinated. I can't even call it selfish because it doesn't even benefit yourself.

2 ( +6 / -4 )

I trust the data the doctors are using rather than newspapers:

https://www.bmj.com/content/372/bmj.n393/rr-4?s=08

And why link to a comment by someone that is not a health care professional making a completely irrelevant comparison between actions directed to two very different populations. It is as "revealing" as finding out diapers for adults have a much higher rates of lethality than diapers for infants.

The really important comparison is between negative side effects with and without vaccines on populations of the same characteristics, but since that would prove the vaccines are safe probably the author of the comment (coming from a deeply antiscientific conspiracy supporting organization) would be against this very clear proof of safety.

In light of the risks of either receiving or not receiving the vaccine, let every person make their own decision without judgement from others.

Since the risk from the infection are much higher than those of the vaccine it is perfectly valid to qualify the decision of not vaccinating as deeply irrational. People are free to make it, but that doesn't make it less irrational.

Indeed, the "antivaxxers" no longer say that because the vaccine promoters had to stop saying they were 100% safe, with all the vaccine-induced side effects and deaths.

People that promote safe and effective measures have always made the argument that vaccines are simply much safer than the infection, antivaxxers were always the only ones misrepresenting this as "100% perfectly safe of everything" but that is just a strawman because they can never disprove the safety of vaccines, even if they try to now misrepresent COVID-19 as non dangerous (since close of 3 million deaths clearly disprove that).

The article also proves what concerned people have been saying all along, that vaccine injury is real and are a recognized risk. Thus, where there is risk there must be choice without judgement or negative consequences.

Why without judgment? it is very clear that choosing not vaccinating is illogical since it carries a much higher risk, why should people be immune from perfectly valid criticism? that is part of their decision. If someone is interested in not being qualified as making irrational decisions the easiest way would be choosing rationally, and if this person is prepared to make a wrong decision he should be also prepared to be called on that.

3 ( +7 / -4 )

Adjuvants are safe, but designed to inflame

No they are not. They cause encephalitis (brain swelling) 100% of the time. Ever wonder why some have seizures. Pharma says it's to kick start your immune system....well...it sure does but those adjuvants (or toxins) are not for the virus in particular.

It’s impossible for experts to predict who’s going to feel fine and who’s not. In the vast majority of cases, any side effect you feel will be over within a few days, and there is no reason for concern.

But it is important that the medical and scientific communities talk about the temporary side effects from these vaccines – and that the public know that there is a very small percentage of adverse reactions.

I am an immunologist who studies the fundamentals of immune responses to vaccination, so part of that responsibility falls on me.

Receiving these vaccines will likely make a lot of people feel crappy for a few days. That’s a far better prospect than long-term illness or death.

[RISKS of COVID vaccine injection #1, #2 and soon #3]: Let's dig into the Negative Side Effects shall we?

Chest pain, Headache, Nausea, Dizziness, Vomiting, Blood pressure increase, Hives, Facial swelling, Lip swelling, Whole body rash, Itchiness (eyes, throat), Analphylactic shock (get your epipen ready), Belle's Palsy (paralyzed on one side of face), Blood clots, Miscarriages, Permanent Disability, Emergency Room visit, Hospitalized, Birth Defect, Life Threatening, Death

Yes, these FDA unapproved, Emergency Use Authorization only, that may void your life insurance (being experimental - check with your provider) vaccines are perfectly 300% safe according to Pharma with a few major caveats here and there of course.

First, these injections do not fit the definition of a vaccine (which is supposed to prevent disease) -

You still can contract the disease and infect others - What in the world? CDC says now you are free to return move around (and infect others?)

Does not prevent hospitalization or death - What? All that waiting for nothing? I cough less. My headache is somehow feeling better than what I would have gotten?

Instead will reduce your cough or severe headache but can give you major headaches, severe fever, weakness and put you out for 24-48 hours PLUS risk of permanent disability, death WITH ZERO LONG TERM DATA (Pharma - Um, science says we don't need long term data so you should be fine and those deaths have nothing to do with the vaccine)

YOUR BODY YOUR CHOICE if you want to inject but make sure you get informed consent because these details will not be presented to you. Risk / Benefit is totally worth the reduction in headache and cough right?

-6 ( +5 / -11 )

No they are not. They cause encephalitis (brain swelling) 100% of the time. Ever wonder why some have seizures. Pharma says it's to kick start your immune system....well...it sure does but those adjuvants (or toxins) are not for the virus in particular.

Mistaken information, not supported by data and easily to demonstrate as false. You understand that many vaccines have adjuvants right? and the vaccinated people do not develop encephalitis as you said, much less 100% of the patients

https://www.cdc.gov/vaccinesafety/concerns/adjuvants.html

The vaccines do not void life insurance, nor they are experimental anymore. The vaccines do prevent disease, complications and death, and also prevent transmission of the disease. Almost everything you comment is easily demonstrated as false, there is no point in just repeating something false if you are not even able to defend that lie.

3 ( +6 / -3 )

It all comes down to this: By getting vaccinated, you protect yourself, your loved ones and your community from a highly transmissible and deadly disease. It may cost you a few days of feeling sick.

That's all that really needs to be said.

I have faced death four times in the last ten years.

The only thing that scares me be being responsible for somebody else's death.

That's what it comes down to. Responsibility to others.

Don't take the vaccine if it scares you, but if you really are that selfish then society owes you nothing in return.

2 ( +6 / -4 )

Some hapless victims are suffering from long-term effects like damaged lungs and hearts.

6 ( +8 / -2 )

nor they are experimental anymore.

They have yet to get regular FDA approval. They have only been approved for emergency use.

-6 ( +4 / -10 )

They have yet to get regular FDA approval. They have only been approved for emergency use.

The previous president fast tracked that. Take it up with him.

2 ( +6 / -4 )

They have yet to get regular FDA approval. They have only been approved for emergency use.

That has absolutely no importance, they are not being experimented on the general population but used for their therapeutic value so they are not experimental anymore. I know it defeats completely your argument but it is true.

1 ( +6 / -5 )

I guess this is good information for those of us living in Japan under age 65 who will be lucky to get vaccinated by around October or November...

2 ( +2 / -0 )

I expect it will have the same effects as the flu shot.

0 ( +2 / -2 )

I had my first Astra shot 3 weeks ago, was good for about 10 hours after then that evening started to feel a bit fatigued, like a cold coming on. Took some paracetamol, was still a bit tired the following day but the day after back to normal. Pretty similar to my 3 colleagues as well but I didn’t take a sickie... :)

2 ( +2 / -0 )

I don’t understand that discussion. All the vaccinations in childhood...nobody of us was asked or could complain or interrupt, society and parents simply knew the need and used their force and that was all. Have you survived it, not asked and taken away your own will and freedom for five minutes? Yes, obviously you have. The same thing has to be done now, because it is quite a global threat, for health, economy, education, everyone’s lifestyle. That has just to be done and enforced, you get your freedom back five minutes later. Of course, this is only meant, if the best vaccines are available and the process is monitored by real doctors with expertise, to avoid too many side effects or obvious dangers on some people with contradicting situations.

0 ( +1 / -1 )

No thanks... I've already had the virus (and only had the sniffles and short term loss of smell) and I trust anti bodies more than this "vaccine".

-1 ( +1 / -2 )

share

www.washingtonpost.com/technology/2021/02/12/china-covid-misinformation-li-meng-yan/

0 ( +0 / -0 )

zichiApr. 5  03:22 pm JST

Some hapless victims are suffering from long-term effects like damaged lungs and hearts.

From the vaccine???

-1 ( +0 / -1 )

My neighbour is a healthcare worker and suffered a fever after her 2nd shot of Pfizer.

Zichi, this thread is about vaccine side effects not covid side effects so your post is potentially misleading.

0 ( +1 / -1 )

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