An expert panel that advises the Centers for Disease Control and Prevention voted unanimously on Saturday to recommend use of Moderna’s Covid-19 vaccine. When CDC Director Robert Redfield signs off on the recommendation — as he is expected to do before the weekend is out — Operation Warp Speed will be able to begin shipping doses of a second vaccine to administration sites across the country.
The Advisory Committee on Immunization Practices met in an emergency session to review data on the vaccine, which received an emergency use authorization Friday evening from the Food and Drug Administration. The ACIP, as the group is known, voted 11 to 0 to support use of the vaccine in people 18 years old and up. Three members of the committee recused themselves because of conflicts of interest.
“This represents progress towards ending this horrific pandemic,’’ Beth Bell, a member of the committee and chair of its Covid-19 vaccines work group, said after the vote was conducted.
Helen Keipp Talbot, an associate professor of infectious diseases at Vanderbilt University, smiled broadly as she voted yes. In an email after the vote, Talbot said she had had to forgo an opportunity to be vaccinated on Saturday in order to participate in the ACIP meeting, but said she could not have been happier to vote.
“I am so pleased we will have more vaccine. I’ll get back in line for my shot,” Talbot said.
The committee is scheduled to meet again on Sunday to vote on what are sure to be difficult recommendations on who should be in the next two priority groups to receive vaccine. Currently health care workers and nursing home residents and staff are being vaccinated in what is known as Phase 1a of the vaccine rollout.
A significant portion of Saturday’s meeting was devoted to rare reports of anaphylaxis in people who have been vaccinated with the Pfizer/BioNTech vaccine. Tom Clark, deputy director of CDC’s division of viral diseases, told the committee that to this point, six cases of anaphylaxis have been confirmed in the U.S. One was in a person who had experienced anaphylaxis after a rabies vaccine injection earlier in life.
A number of other possible anaphylaxis cases have been reported and are being investigated, Clark said, with some already discounted. As of early Saturday, 272,001 doses of the Pfizer vaccine had been administered across the country.
Clark, who is in charge of “post implementation” for the vaccine task force — in other words, monitoring vaccine safety and effectiveness — said the people who developed anaphylaxis after vaccination did not receive vaccine from the same production lot, which would rule out a problem with a particular batch of vaccine. He also said to date there haven’t been signs of geographic clustering of cases, even though the first two reported U.S. cases were nurses in Alaska.
Early in the session, Jacqueline Miller, Moderna’s senior vice president for infectious diseases development, told the ACIP that there had been three reports of anaphylaxis in its Phase 3 trial. Two cases were in the placebo arm of the trial; one vaccine recipient who had a shellfish allergy developed anaphylaxis 63 days after being vaccinated — too long an interval for the vaccine to be the trigger.
Still, anaphylaxis didn’t show up in the Pfizer vaccine’s Phase 3 trial either, but was seen within the first day of the vaccine’s rollout in the United Kingdom, where two nurses developed it.
FDA and CDC authorities are assuming receipt of the Moderna vaccine may also induce this reaction in rare cases and are instructing people who have had severe allergic reactions to any components of the vaccines to forgo vaccination.
Both vaccines consist of messenger RNA encased in lipid nanoparticles; there are no preservatives in these vaccines. In a call with physicians last weekend, a CDC scientist said people could be allergic to a part of the lipid nanoparticle known as polyethylene glycol, or PEG, which is a component in other injectable medicines.
(The full ingredients of the Moderna vaccine are listed on page 4 of the FDA’s letter confirming the issuance of the EUA for use of the vaccine.)
The CDC is instructing places that are administering vaccine to have on hand epinephrine — the drug contained in EpiPens — to treat allergic reactions if they occur. It is also recommending that everyone who is vaccinated should be monitored for 15 minutes; people who have had a history of anaphylaxis should be monitored for 30 minutes.
The ACIP was also told of the occurrence of a fourth case of what may be an unusual side effect of immunization with the Moderna vaccine — facial swelling in a person who had previously received cosmetic dermal filler injections. The issue was first raised on Thursday during the meeting of an FDA advisory committee.
Miller said the cases have all either resolved or are in the process of resolving; none of these people required epinephrine, but were treated with antihistamines.
During the meeting, ACIP members asked whether the Moderna vaccine vials are likely to contain extra doses of vaccine. Confusion occurred last week during the rollout out of the Pfizer vaccine when people administering the vaccine found they had significant amounts of vaccine left in the five-dose vials after drawing out all the prescribed doses. Without explicit approval from the company to use the extra vaccine, hospital pharmacists at some health care systems threw it away.
In some circumstances, it is not permissible to extract more doses from a vial than the label stipulates, but the FDA said in the context of a pandemic, extra doses should not be wasted. Some of the Pfizer vials contain six or seven doses.
Moderna executives said that while vials of all liquid vaccines contain a small amount of extra material, the company believes most will contain only 10 full doses. In some cases an 11th dose may be present and can be used, they said. Nancy Messonnier, director of CDC’s National Center for Immunization and Respiratory Diseases, said the agency will be issuing clinical guidance on this issue.