If you feel lousy for a day after you get your second COVID-19 shot, there’s a reason why, the head of Maine’s CDC said Tuesday.

“Here’s what’s going on,” Dr. Nirav Shah said.

“The feeling you feel after you get your shot, whether it’s your first or second shot, of being rundown, a little flu like, that is your body’s immune system” at work, he said. “The reason that more folks feel it after their second shot as opposed to their first shot, is that the first shot primes the pump. It tells your immune system, ‘be ready. Get ready.”

The second shot fortifies, or makes stronger, the body’s immune system to actually go into high gear, Shah said. “That’s why you feel a little bit crummier after your second shot.”

Typically the crummy feelings last six to 12 hours. “The next day you’re OK,” Shah said.

If you don’t feel sick, tired, or have body aches, “it’s OK,” Shah said. It doesn’t mean the vaccine isn’t working.

It does not mean one vaccine is working better than another, he said. “The vaccine is working regardless of whether you feel crummy after your first or second dose,” he said.

Shah emphasized that when doctors talk about adverse side effects from the vaccine, they are not talking about feeling poorly for a day.

“Don’t be scared of getting the shot,” he said. “You might feel a little crummy a bit, but it’s absolutely worth it compared to the benefit you get.”

Related Headlines


Only subscribers are eligible to post comments. Please subscribe or to participate in the conversation. Here’s why.

Use the form below to reset your password. When you've submitted your account email, we will send an email with a reset code.

filed under: