U.S.-based Pfizer and its Germany-based partner BioNTech plan to give volunteers who received a placebo in its COVID-19 vaccine trial an option to receive a first dose of the vaccine by March 1, 2021.
The U.S. Food and Drug Administration and a panel of its outside advisers have expressed concerns over Pfizer’s “unblinding” plan, saying it could make it harder to continue collecting data on safety and effectiveness needed to win full FDA approval of the vaccine.
The companies said that trial participants who received the placebo will have two doses of the vaccine reserved for them within the study.
Participants will be given the “Vaccine Transition Option,” the choice to learn whether they received the investigational vaccine or placebo. Those who find out they received the placebo will be given the option to receive the investigational vaccine while being able to stay in the study.
If they choose the vaccine option, they will receive the first dose by March 1, and the second dose about 21 days later, “and follow an updated study schedule that includes follow-up and illness visits.”
Britain’s medical regulator has said that anyone with a history of anaphylaxis, or severe allergic reactions to a medicine or food, should not be given the Pfizer-BioNTech COVID-19 vaccine.
The FDA has said that most Americans with allergies should be safe to receive the vaccine. It said that only people who have previously had severe allergic reactions to vaccines or ingredients in this particular vaccine should avoid getting the shot.
Pfizer said in a statement to news outlets in December that it was working to learn more details about the reported adverse reactions.
“We will closely monitor all reports suggestive of serious allergic reactions following vaccination and update labeling language if needed,” a Pfizer spokesperson said. “The prescribing information has a clear warning/precaution that appropriate medical treatment and supervision should always be readily available in case of a rare anaphylactic event following the administration of the vaccine.”
Common side effects of the vaccine include pain at the injection site, tiredness, and fever, according to the FDA.
“Of note, more people experienced these side effects after the second dose than after the first dose, so it is important for vaccination providers and recipients to expect that there may be some side effects after either dose, but even more so after the second dose,” the agency says on its website.
According to the FDA, the Pfizer-BioNTech COVID-19 vaccine contains messenger RNA (mRNA), which is genetic material.