RICHMOND, Va. (WRIC) — Are side effects to a COVID-19 vaccine something to celebrate? Nurse Manager for Richmond and Henrico’s health district Amy Popovich says they usually are.

“These are good signs,” she said. “That means your antibodies are preparing. They’re preparing that response to be able to fight off any [COVID] exposure.”

Popovich said side effects are varying so much among people simply because we all have different immune systems. Studies show most people have worse side effects after their second doses.

According to health experts, that’s because the body is already primed from the first shot and doing the hard work after getting the second.

“It’s not because the vaccine gave you the virus,” Popovich said. “It’s because your body is building up an immune response.”

One Minnesota-based doctor explained it in an easy way to understand.

When you take a two-dose vaccine, “the first dose is the first time for your body to see the spike protein that the COVID-19 vaccines produce, and your body begins to develop an immune response,” said Dr. Melanie Swift with the Mayo Clinic. “But that happens slowly. Then when you come back with a second dose, your body is ready to attack it,” she said.

Amy Sheets from Chesterfield said she had reactions to both Moderna doses. About a week after her first shot, hives appeared on her face. She also found a “really big red” rash at the injection site. That’s known casually by some as “COVID arm.”

“It was hot. It was a little itchy. I knew immediately what it was,” Sheets told 8News in an interview Thursday. After that went away and she got the second shot, Sheets said she woke up the next morning feeling pretty rough.

“I felt a little bit like a truck had hit me. I was really tired,” she said.

In about a week, she will be fully vaccinated and has no regrets.

“It’s just a gamble that we take,” Sheets said. “The tradeoff of feeling rotten for 12 or 24 or 48 hours is so much better than actually getting the illness.”

Health experts say if you didn’t have side effects, don’t worry. That doesn’t mean your vaccine didn’t work. Every body just reacts to things differently.

However, if you have really intense side effects like shortness of breath or severe pain, you’re told to see a medical professional as soon as possible.