President Donald Trump's coronavirus vaccine czar said Tuesday that Pfizer's and Moderna's Covid-19 vaccines are safe, with only 10% to 15% of volunteers reporting side effects that were "significantly noticeable."
The side effects, which come from the vaccine shots, can last up to a day and a half, said Dr. Moncef Slaoui, who is leading the Trump administration's Covid-19 vaccine program Operation Warp Speed. The people who've suffered from side effects have reported redness and pain at the injection site as well as fever, chills, muscle aches and headaches, he said, adding most people have no noticeable side effects.
"The longer, more important kind of adverse events such as some autoimmune disease or others have not been reported in a different way between the placebo group and the vaccine group in these two trials, which is very reassuring," he told The Washington Post. "I always make sure we say that [while] we know the short term and I'm going to call it midterm effects of the vaccine is now well understood, the very long-term safety is not yet understood by definition."
Slaoui's comments come as states prepare to distribute a Covid-19 vaccine in as little as two weeks. A Centers for Disease Control and Prevention panel is scheduled to vote later Tuesday on who will be first to get a vaccine once one has been authorized by U.S. regulators.
Last month, doctors told the Advisory Committee on Immunization Practices, an outside group of medical experts that advise the CDC, that officials should talk more about the potential side effects of the vaccines so the public knows what to expect and aren't scared away from getting a second dose. Both companies' vaccines require two doses about a month apart to achieve maximum effectiveness.
"We really need to make patients aware that this is not going to be a walk in the park," Dr. Sandra Fryhofer of the American Medical Association told the CDC advisory group on Nov. 23. "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."
Moderna and Pfizer have acknowledged that their vaccines could induce side effects that are similar to symptoms associated with mild Covid-19, such as muscle pain, chills and headache.
Participants in Moderna's and Pfizer's coronavirus vaccine trials told CNBC in September that they were experiencing high fever, body aches, bad headaches, daylong exhaustion and other symptoms after receiving the shots. While the symptoms were uncomfortable, and at times intense, the participants said they often went away after a day, sometimes sooner, and that it was better than getting Covid-19.
While the long-term side effects are not well understood yet, Slaoui said it is important to get a vaccine deployed as soon as possible as the pandemic is "killing 2,000 or more than 2,000 people a day."
"These vaccines with 95% efficacy are an insurance against that," he said, adding the vaccines have already been tested in more than 50,000 people. "It will be very important for the most susceptible parts of our population get these vaccines. And we will be looking at the safety of these vaccines in real life through very elaborate ... processes and report on it on an ongoing basis."
During the advisory meeting last week, Patsy Stinchfield, a Children's Minnesota nurse practitioner, said officials and drugmakers could try talking about the side effects in a more positive way. She said they could use language such as "response" instead of "adverse reaction."
"These are immune responses," said Stinchfield, a past voting member of the committee. "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. It sounds like in some of these trials, maybe even having to stay home from work."