Covid-19 vaccine side effects are signs that the shots are helping to protect against the disease, said former FDA chief Dr. Margaret Hamburg on Thursday opposite CNBC.
"The data tell us that this vaccination produces a fairly routine response at the time of administration, but it is noteworthy when you receive the vaccine," she said on Squawk Box. "You will know when you will receive the vaccine, but that will also show you that it works and that your body is reacting," added Hamburg, who headed the regulator in the Obama administration from 2009 to 2015.
The Hamburg statements come when the vaccine committee of the Food and Drug Administration meets on Thursday whether Pfizer and German partner BioNTech should vote for the emergency approval of the Covid-19 candidate. The non-binding decision by the panel of experts is a final step before the FDA is expected to approve the vaccine for limited use.
The agency will meet next week at the request of Massachusetts-based Moderna to obtain the same approval. The vaccine is similar to Pfizer's in that they both take a new approach that uses genetic material to trigger an immune response.
Pfizer's vaccine was approved by regulators in the UK last week, where the first shots were given on Tuesday for non-trial participants. However, the two allergic reactions reported by UK health workers prompted UK regulators to advise people with a history of "significant" allergic reactions to avoid the vaccine for the time being.
Coronavirus vaccine development deadlines have been hastened this year by drug makers and governments alike in hopes of finding a solution to the devastating pandemic that killed at least 1,571,890 people worldwide, according to Johns Hopkins University. The US recorded a record 3,124 deaths on Wednesday.
Both Pfizer's and Moderna's vaccines were shown to be more than 94% effective in preventing symptomatic Covid-19, according to data from large-scale clinical trials.
Some of the reported side effects are "local swelling, irritation, pain, fatigue, sometimes headache," said Hamburg. "A percentage of the patients had chills and a slight fever."
Dr. Moncef Slaoui, who leads the Trump administration's vaccine development efforts, has defended the safety of Pfizer and Moderna vaccines. He said earlier this month that "significantly noticeable" side effects from the admissions were reported in only 10% to 15% of study participants, which may lasted up to a day and a half.
Both Pfizer's and Moderna's vaccines require two doses. Some doctors have tried to raise awareness of the side effects so that vaccine recipients aren't deterred from getting the second shot.
"We really need to make patients aware that this is not going to be a walk in the park," said Dr. Sandra Fryhofer of the American Medical Association in November at an advisory panel meeting of the Centers for Disease Control and Prevention. "You will know you had a vaccine. You probably won't feel wonderful. But you have to come back for that second dose."