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You Asked: Do COVID-19 Vaccines Have Side Effects?

Iowa health officials say the first shipments of COVID-19 vaccines will go to the state's frontline health care workers and residents and staff of nursing homes.

As Iowa started seeing its first shipments of COVID-19 vaccinations this week, here are answers to some of your general questions about the vaccines.

Iowa began receiving the first doses of COVID-19 vaccines this week, and state officials anticipate receiving more weekly. The first doses will go to frontline health care workers and staff and residents of nursing homes, but officials haven't said what groups will be prioritized after. Meanwhile, here are answers to some of your general questions about the vaccines.

Will I have to pay for the vaccine?


Vaccine providers will be able to bill insurance for a fee to administer the vaccine, but will not be able to charge you. They can seek reimbursement for uninsured patients from the Health Resources and Services Administration’s Provider Relief Fund.

Can I get or spread COVID-19 from the vaccine?


There are several different types of vaccines. Rotavirus and MMR vaccines use a live but weakened version of the virus to teach your body to develop long-term immunity to a disease. Flu and rabies shots use an inactive version of the virus, but that’s why you don’t develop long-term immunity from those viruses.

The COVID-19 vaccine doses developed by Pfizer-BioNTech and Moderna use a new type of vaccine, an mRNA vaccine. This type of vaccine has been in development for about three decades, but is only now being used for COVID-19. According to the CDC, mRNA vaccines teach your cells how to make a protein – or even just a piece of a protein – that triggers an immune response inside our bodies. That immune response, which produces antibodies, is what protects you from getting infected if the real virus enters our bodies.

That being said, the Pfizer-BioNTech and Moderna vaccines require two doses to be effective – more similar to many childhood vaccinations than getting a flu shot. So, once you do receive a vaccination, you may have to receive a follow-up.

But experts say while evidence suggests the vaccine is very effective in preventing severe illness from COVID-19, it's still unclear if those who get the vaccine will be able to spread the virus.

"That's some of the research that still needs to be done," said Pat Winokur, executive dean of the University of Iowa's Carver College of Medicine, who oversaw UI's Pfizer vaccine trial. "We don't know that the vaccine reduces shedding. My guess is it does, at least partially."

Do I still have to wear a mask once I have the vaccine?


According to NPR’s Shots, studies of the new vaccines only measured whether vaccinated people developed symptoms, not whether they got infected. It's possible that they got mild infections — not enough to make them ill, but enough to pass the virus on to others.

The CDC is calling for those who are immunized to continue wearing masks and practicing safe physical distancing until more is learned.

Iowa health experts are calling on Iowans to continue to follow public health recommendations to slow the spread of the virus until the vaccine is widely distributed.

"What we are telling people is they do need to continue to practice social distancing, wearing masks and hand washing. Vaccines are not perfect. We know even from the data for Pfizer that 5 percent of people did not respond," Winokur said.

"And it's really important also to continue to set that kind of model for other people, because there are a lot of people out there that are not able to get vaccine."

What are the side effects of the vaccine?

Side effects include a sore arm, body aches, and a low-grade fever, Winokur said.

She said side effects are typically mild to moderate and said about 9 percent of people had side effects that disrupted daily activities.

"But that disruption was usually for 24 hours, maybe 48," Winokur said. "This is an expected side effect of this vaccine. It is actually not a bad thing. It suggests that your body is mounting an immune response to this vaccine. We want your body to do that."

WITF, a station in Pennsylvania, asked that question of Johns Hopkins Bloomberg School of Public Health’s Dr. William Moss.

He said at this point, we only know the short-term side effects – which appear in about 5-15 percent of participants.

Those include inflammation, soreness at the injection site, a low-grade fever, headaches, muscle aches and fatigue. These can last from 12 to 36 hours after vaccination.

How effective are the vaccines?

Only the Pfizer-BioNTech has been given emergency use authorization by the Food and Drug Administration. According to the FDA’s authorization letter, it is 95 percent effective seven days after the second dose. According to Moderna’s data, it is 94.1 percent effective.

Contact Lauren at lchapman@wfyi.org or follow her on Twitter at @laurenechapman_.

This story was produced by Side Effects Public Media, a news collaborative covering public health.