So THAT’S Why You Feel Like Crap After Your COVID Or Flu Shot

A new COVID-19 shot is here, and the Food and Drug Administration is recommending everyone 6 months old and up get it. Infectious disease experts have said the new vaccines, which target the KP.2 variant that’s behind the most recent wave of infections, do a better job at preventing serious outcomes like hospitalization and death.

If it’s been a second since you’ve gotten a booster shot, then let this serve as a quick reminder that it’s very normal — and common — to feel under the weather for a day or two after you get vaccinated, and flu-like symptoms are a sign the shot is doing its job.

“These symptoms may be reflective of a more robust immune response to the vaccine, which leads to longer-lasting and stronger protection,” Dr. Scott Roberts, a Yale Medicine infectious disease specialist, told HuffPost.

According to the FDA, the new shots are expected to trigger side effects similar to those of the previous COVID-19 vaccines: headaches, fatigue, mild fevers and muscle pains.

Pain at the injection site is frequently reported, as is a red, itchy rash, which has been nicknamed “COVID arm.” Some individuals may also experience gastrointestinal issues, like diarrhea and nausea, as well as swollen lymph nodes.

The vaccine essentially tricks the body into responding as if you have an infection. As a result, “the side effects of the vaccine or booster can feel like a milder version of a COVID or flu infection when the immune system is stimulated, even though there is no actual infection happening,” Dr. Anne Liu, an infectious disease and allergy/immunology specialist with Stanford Medicine, told HuffPost.

The side effects vary from person to person, according to Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security and an infectious disease expert. And if you recently had COVID-19? Well, you might have a stronger reaction since your immune system was recently primed to go after the coronavirus, Adalja said.

When the immune system is stimulated, as it is when you’re vaccinated, it releases various molecules that trigger symptoms like muscle aches, Adalja said.

These side effects indicate the vaccine is doing its job. One study found that the more post-vaccine side effects you have, the stronger your immune response is. The study also found that experiencing chills, tiredness and headaches after getting one of the COVID-19 vaccines was linked to higher levels of neutralizing antibodies up to six months later.

With that said, many people don’t experience any symptoms after getting vaccinated — and that’s OK, too.

“Most people have minimal side effects to the COVID vaccination, but almost all of them form excellent memory responses to the vaccination,” Liu said.

Adverse events are uncommon, but they do happen. If you experience chest pain, shortness of breath or an irregular heartbeat, you should seek medical treatment immediately. These symptoms could be due to serious cardiovascular complications, like myocarditis or pericarditis.

“These are very rare, and in almost all cases the benefits of the vaccine outweigh the risk of these side effects,” Roberts said.

If you want to knock out your COVID-19 and flu shots at the same time, go ahead. The Centers for Disease Control and Prevention confirmed it’s safe and effective, but don’t be alarmed if you feel extra crummy after.

According to the CDC, you’re more likely to experience these common side effects — fatigue, headaches and muscle aches — if you get the two shots together. Fortunately, these side effects are typically mild and should clear up within a few days.

“Most people tolerate getting the COVID booster and the flu shot at the same time with no or only mild side effects,” Liu said.

The best thing you can do, according to the CDC, is get some rest. Data has suggested that laying low after the shot boosts your immune response and helps your body restore and repair itself.

If your arm’s sore or itchy, apply an ice pack and try to move it up and down throughout the day. You’ll also want to drink plenty of fluids if you have a high temperature since a fever can dehydrate you.

For those with a fever or aches and pains, Roberts suggested taking ibuprofen and acetaminophen. Just make sure to check in with a doctor first to see if it’s safe for you to take the medication. If you do use them, make sure to swallow the pills after the shot. Some doctors recommend not taking them before vaccination since they may blunt the immune response, Roberts said.

Other than that, remember that time is on your side. These side effects are typically short-lived and you should bounce back within a couple days.