Clarity urged on side effects of new vaccines

US public health officials are calling on drugmakers to release detailed information on the side effects of their coronavirus vaccines after participants in trials complained of high fever, body aches, headaches and exhaustion.

Given that Pfizer's and Moderna's vaccines need to be taken in two separate doses, Sandra Fryhofer of the American Medical Association fears that if people have severe side effects with the first shot, that could deter them from getting the second one.

"We really need to make patients aware that this is not going to be a walk in the park," Fryhofer said in an online meeting with the Advisory Committee on Immunization Practices, or ACIP, a group that advises the Centers for Disease Control and Prevention, or CDC.

"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."

Three COVID-19 vaccines－from Pfizer and BioNTech; AstraZeneca and Oxford University; and Moderna－have been found to have efficacy of more than 90 percent. The producers are seeking approval for emergency use by the US Food and Drug Administration.

On Wednesday, Pfizer's vaccine was approved for use in the United Kingdom, a first in a Western country.

Participants in Moderna's and Pfizer's coronavirus vaccine trials experienced side effects that cleared up in a day or more.

A 30-year-old woman, who didn't want to be named but who is taking part in trials for AstraZeneca's vaccine in New York, said she experienced several adverse symptoms.

"I had body aches, fatigue and a headache. I also experienced mild pain and soreness at the injection site," she told China Daily."I experienced symptoms approximately 12 hours after I received the injection. The body aches and headache were alleviated by taking ibuprofen. I would say the symptoms lasted about 12 hours. Soreness at the injection site lasted about 24 hours."

'A little off-guard'

A nurse checked her vital signs, did a physical examination and asked about her medical history before giving her the initial injection. She will visit the same center for a second shot in four weeks although she doesn't know if she was given a placebo or the vaccine. In trials, half the people are given the vaccine and the other half a placebo.

She added:"I was made aware of exactly what to do in the event that I experienced more serious side effects (for example, shortness of breath or fever). The side effects I experienced, while uncomfortable, were mild and nothing beyond what one might expect during a mild case of the flu. I've never had the flu, or body aches and general fatigue, so I was caught a little off-guard."

All of the vaccine makers have said patients could experience mild coronavirus symptoms. But doctors want them to explain further how it could affect different patients.

Luke Hutchison, 43, a computational biologist, volunteered for a trial of Moderna's vaccine. After he got the second injection, his arm swelled up.

He also experienced bone and muscle aches, a 38.9 C fever, shaking and cold and hot flushes. While his symptoms went away in 12 hours, he told the journal Science: "Nobody prepared me for the severity of this."

Pfizer's vaccine, the fastest ever produced, took nearly 10 months to develop. In the past, similar vaccines usually took a decade.