What are the side effects of the COVID vaccines? Here’s what to expect

Infectious diseases experts agree the only way to overcome the pandemic is for the majority of the population to receive a coronavirus vaccine when one becomes available.

But like most regularly recommended vaccines, the one for COVID-19, which will be administered in two doses weeks apart, doesn’t come without side effects. Most people who have participated in clinical trials report fevers, headaches, fatigue, muscle aches and soreness around injection sites.

“Severe” side effects of one of the coronavirus vaccine candidates from biotechnology company Moderna included fatigue in 9.7% of participants, muscle pain in 8.9%, joint pain in 5.2%, headaches in 4.5% and redness at injection sites in 2%, according to the company.

The vaccine from Pfizer/BioNTech reported similar, slightly lower numbers. Most of the reported reactions are short lived, both companies say.

Arnold Monto, an epidemiologist at the University of Michigan School of Public Health, told Science that the rate of reactions COVID-19 vaccine trial participants experienced is higher than what the public may be used to, like with the flu vaccine.

Still, experts say the side effects seen are normal and not dangerous, and should not scare people away from getting vaccinated.

“These are immune responses,” Patsy Stinchfield, a nurse practitioner at Children’s Hospitals and Clinics of Minnesota, said during a meeting Monday with Centers for Disease Control and Prevention advisors, according to CNBC.

“And so if you feel something after vaccination, you should expect to feel that. When you do, it’s normal to have some arm soreness or fatigue, some body aches and maybe even a fever,” Stinchfield added.

‘Any vaccine can cause side effects’

The CDC says that “any vaccine can cause side effects. For the most part these are minor… and go away within a few days.”

For example, common side effects for the flu vaccine include soreness, headache, fever, nausea, muscle aches and occasionally fainting — much like those of the COVID-19 vaccine candidates.

Side effects of another regularly recommended vaccine, the MMR (measles, mumps, rubella) shot, include soreness, redness or rashes around injection sites or all over the body, fever or swelling of the cheek and neck glands.

The DTaP (Diphtheria, Tetanus, Pertussis) vaccine commonly causes fever, fussiness, fatigue, loss of appetite and vomiting on occasion, the CDC says.

Chicken pox vaccines are known to cause sore arms, fever, mild rashes at injection sites and temporary joint pain and stiffness.

Some clinical trial participants experienced intense reactions from the COVID-19 vaccines, media outlets report. Some said they felt blindsided by the severe side effects.

“I started shaking. I had cold and hot rushes,” Luke Hutchison, a computational biologist who volunteered in the Moderna COVID-19 vaccine trial, told Science. “I was sitting by the phone all night long thinking: ‘Should I call 911?’”

He told the outlet his muscle aches and 102 degree Fahrenheit fever were “unbearable… Nobody prepared me for the severity of this.”

However, 12 hours after his injection, Hutchison’s symptoms resolved.

This is why some health experts say transparency about the vaccination process is key to gaining the public’s trust in the vaccine and to ensure them what they may feel is normal.

“We really need to make patients aware that this is not going to be a walk in the park,” Dr. Sandra Fryhofer, an internal medicine physician and board member of the American Medical Association, said during a virtual meeting with the Advisory Committee on Immunization Practices, CNBC reported.

“They are going to know they had a vaccine. They are probably not going to feel wonderful. But they’ve got to come back for that second dose.”

Second dose usually more intense than first

John Yang, a journalist for PBS NewsHour who volunteered in Moderna’s Phase 3 COVID-19 vaccine clinical trial, told NPR the first dose “really wasn’t that bad….fatigue was the main issue.”

But the second dose “really laid me low and very quickly,” Yang told the outlet. “But as that came on faster, it also resolved faster. I got the shot on Tuesday. By Thursday, I was fine.”

More intense side effects after the second shot “mean the vaccine is working well… [It] means you had such a good immune response to the first dose and now you are seeing the effects of that,” Drew Weissman, an immunologist at the University of Pennsylvania who co-invented a technique used in both the Moderna and BioNTech vaccines, told Science.

“We’re going to have to accept that there are going to be risks — nothing we do in this world is risk-free,” Dr. Grace Lee, a professor of pediatrics at the Stanford University School of Medicine and a member of the Advisory Committee on Immunization Practices for the CDC, told NBC.

“We could wait six months, a year or two years to have sufficient data, but should we withhold the vaccine from the population for two years because we want perfect data?” Lee said, according to NBC. “Of course, we want perfect data, but given where we are in the pandemic right now, we have to find that balance.”