- The shots were generally better tolerated by people over 64 who are also among the most vulnerable to the disease than for younger people.
- A handful of people experienced rare side effects like intractable nausea or vomiting and facial swelling, the FDA said.
Fatigue, headaches and muscle pain are the most common side effects from Moderna's Covid-19 vaccine, along with some rare symptoms like intractable nausea or vomiting and facial swelling that are likely triggered by the shots, according to new data released Tuesday by the Food and Drug Administration.
On a positive note, the data shows the shots were generally better tolerated by people over 64 who are also among the most vulnerable to the disease than for younger people.
Side effects to vaccines are common. It's actually an immune response that indicates the shots are working as intended, doctors say. Many physicians are advising the public to brace for some stronger-than-usual side effects from the Covid-19 shots than, say, a typical flu shot, and to possibly take a day or two off work to recover.
Moderna's vaccine, which was endorsed by FDA staff Tuesday, is more than 94% effective and safe enough to meet agency's bar for emergency use, according to the report. But the regulatory agency's analysis noted that the vaccine is associated with common and unpleasant, but not necessarily dangerous side effects.
More than 9 in 10 participants who received the vaccine felt pain at the injection site, almost 7 in 10 felt fatigued and roughly 6 out of 10 had headaches or muscle pain, the FDA said.
More than 44% of people who received the vaccine reported experiencing joint pain and over 43% reported chills. The FDA noted that more severe "serious adverse reactions occurred in 0.2% to 9.7% of participants" and were more common after the second dose than the first. Like Pfizer's Covid vaccine, which the FDA authorized last week, Moderna's vaccine similarly requires two shots separated by a few weeks.
Nearly 15% of vaccine participants got a fever after either the first or second dose, according to the FDA.
Some side effects were hard to shake, though most resolved within a week, the FDA said. Fewer than 6%, reported symptoms that persisted for at least a week after getting the shot, but that was similar to the placebo group. Some of the trial participants had a fever that lasted more than a week; seven were in the vaccine group and four got the placebo, the FDA noted.
The FDA said there were seven "serious adverse events" in the trial, but none of them was fatal. Four were attributed to the vaccine by trial investigators and Moderna, including intractable nausea and vomiting, facial swelling and rheumatoid arthritis.
The FDA staff also recommended monitoring people who get the vaccine for possible cases of Bell's palsy, saying it's not necessarily a side effect but worth watching out for after four of the trial's 30,000 participants got the condition, which causes half of your face to droop.