Scientists: COVID-19 vaccine expected to have flu-like side effects

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It will also require two doses to work

The COVID-19 vaccine is slowly making progress toward becoming available, but experts say the side effects may pose a problem with getting everyone on board with taking it.

Kaiser Health News reported via NBC News that like many other vaccines, it will require two doses to work with injections that must be performed weeks apart, according to Pfizer protocols. Energy-draining flu-like symptoms are expected to occur in some people, scientists expect.

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Among the symptoms are fever, muscle aches and sore arms that could last for days and cause some people to have to take off from school or work.

Early trials of several COVID-19 vaccines have data indicating consumers should be ready for side effects that could disrupt daily life, although they’re technically mild.

William Gruber, Pfizer’s senior vice president of vaccine clinical research and development, told health-oriented news website Stat he believed the side effects were similar to standard adult vaccines, but likely worse than a flu shot or Pfizer’s pneumonia vaccine, Prevnar.

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Adult side effects for vaccines include mild fever, chills and feelings of tiredness according to, which is managed by the Office of Infectious Disease and HIV/AIDS Policy, U.S. Department of Health and Human Services.

“We are asking people to take a vaccine that is going to hurt,” Dr. William Schaffner, a professor of preventive medicine and health policy at Vanderbilt University Medical Center, told Kaizer Health News. “There are lots of sore arms and substantial numbers of people who feel crummy, with headaches and muscle pain, for a day or two.”

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He said that convincing people who have those symptoms to come back for a second dose in the next few weeks could prove difficult.

According to Saad Omer, director of the Yale Institute for Global Health, the way health experts explain the side effects to the public will be important.

“There’s evidence that suggests that if you frame pain as a proxy of effectiveness, it’s helpful,” he said. “If it’s hurting a little, it’s working.”

Data from Pfizer released earlier this week indicates that the COVID-19 vaccine is 90% effective at preventing the disease caused by the coronavirus. It’s anticipated that the pharmaceutical company will file an emergency-use application with U.S. regulators by the end of the month.

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