Justin Sullivan | Getty Images
The Centers for Disease Control and Prevention’s independent committee on vaccines recommended reformulated booster vaccines that target the latest omicron subvariants.
The panel voted 13 to 1 Thursday in favor of the shots after reviewing available safety and effectiveness data in a nearly seven-hour meeting. CDC Director Dr. Rochelle Walensky has yet to give the final sign-off before pharmacies can begin administering the boosters, but approval is expected to follow quickly.
Pfizer’s omicron boosters are for people 12 years of age and older, while Moderna’s updated shots are for adults 18 years of age and older. Eligible age groups can receive boosters at least two months after completing their main series or most recent booster with old dams.
Pfizer plans to ask the Food and Drug Administration to also authorize the new boosters for children ages 5 to 11 in early October, company executives told the committee Thursday.
The original vaccines will no longer be used as a booster in people 12 years of age and older now that the reformulated vaccines are online.
Public health officials expect another wave of Covd infection this fall as immunity from old vaccines wanes, more contagious omicron subvariants spread and people spend more time indoors as the weather it gets colder and families get together for the holidays.
The CDC and FDA hope the new boosters will provide longer-lasting protection against infections, minor illnesses, and serious illnesses. The reformulated traits target omicron BA.5, the dominant variant of Covid, as well as the strain that emerged in China more than two years ago.
The United States has so far gotten 171 million doses of the new boosters from Pfizer and Moderna. More than 200 million people are eligible for the shots, according to the CDC. CDC official Dr. Sara Oliver told the committee Thursday that there should be enough vaccine supply to meet demand this fall.
There are no human data for omicron BA.5
There is no human trial data on the new BA.5 boosters, so it is unclear how they will perform in the real world. The CDC and FDA used human data from clinical trials to target the original version of omicron, BA.1, which elicited a stronger immune response than older vaccines.
Pfizer and Moderna were originally developing omicron drivers to target BA.1, but the FDA asked the companies to switch gears in June and develop BA.5 traits after the subvariant became dominant. The decision to focus on BA.5 did not leave enough time to wait for data from human trials before the fall vaccine launch.
The lack of human data for BA.5 vaccinations has caused some controversy, but Dr. Peter Marks, a senior FDA official, said the agency followed the same process used for years with strain changes to to flu shots. Flu vaccine strains are also being changed without human clinical data, Marks said Wednesday.
Dr. Pablo Sanchez, the only committee member to vote against the shots, called the recommendation premature and said the US should have waited for human data before proceeding with reinforcements.
“There are already a lot of vaccines — we need the human data,” said Sanchez, a professor of pediatrics at Ohio State University. But Sanchez said he believes the new reinforcements are safe and will likely get one himself.
CNBC Health and Science
Read CNBC’s latest global health coverage:
Panel member Dr. Oliver Brooks, chief medical officer of Watts HealthCare Corporation in Los Angeles, asked why the FDA decided to go with a BA.5 vaccine when clinical data are available for BA.1 injections that the vaccine manufacturers were originally developing. Brooks ended up voting in favor of the firings.
But Dr Sarah Long, also a member of the committee, said there was no reason to expect the BA.5 boosters to be inferior to the old shots, as they also included the original strain of Covid, and had the potential to reduce hospitalizations and deaths towards autumn and winter. Long also voted in favor.
Mouse studies
FDA and CDC officials have said that the omicron BA.1 and omicron BA.5 boosters are similar enough that the immune response data from the BA.1 shot should give a good indication of how the BA injections are performing. 5. Omicron BA.1 and BA.5 are closely related with a difference of four mutations, according to Dr. Jacqueline Miller, who works in vaccine development at Moderna.
Moderna completed enrollment in clinical trials on BA.5 injections last week and should have results by the end of the year, Miller told the CDC committee Thursday. Pfizer’s clinical trial is also ongoing, although the company has not said when it expects results.
The health agencies also reviewed data on BA.5 traits from mouse studies. Moderna presented data showing that BA.5 injections boosted antibodies in mice more than fourfold compared to the old ones. Mice express the same cellular protein as humans that the virus attaches itself to. Pfizer’s BA.5 booster boosted antibodies 2.6-fold in mice compared to the original vaccine.
security
According to the FDA, the most common side effects in human trials of BA.1 injections were pain, redness, swelling at the injection site, fatigue, headache, muscle pain, joint pain, chills, nausea, vomiting, and fever .
Oliver, the CDC official, told the committee that health officials do not expect any difference in the safety profile of the BA.1 and BA.5 traits because the subvariants differ by only a few mutations.
But Oliver noted that the risk of myocarditis after a BA.5 booster injection is unknown. There is an elevated risk of myocarditis among young men and teenagers after the second dose of the Pfizer and Moderna injections, but the risk of myocarditis from Covid infection is greater, according to the CDC.
“We know that the risk of myocarditis is unknown, but we anticipate a risk similar to that seen after monovalent vaccines,” Oliver said. Monovalent vaccines are the older vaccines that have been given to millions of people in the US over the past two years.
Old vaccines losing effectiveness
The original vaccines, which were first licensed in December 2020, no longer offer significant protection against infection because the virus has mutated so much over the past two years. The traits were developed against the first strain that emerged in China, so they no longer fit the omicron subvariants that are spreading.
Infections, hospitalizations and deaths have declined dramatically since the massive wave of omicron infections last winter, but have plateaued this summer at a stubbornly high level. Omicron BA.5 is the most contagious and immune evasive variant to date, and breakthrough infections have become increasingly common as a result.
The effectiveness of the old vaccines against hospitalization also declined after the BA.5 omicron became dominant. A third dose was 77 percent effective in preventing hospitalization four months after receiving the vaccine, but protection declined after 120 days to 34 percent, according to CDC data. A fourth dose in people aged 50 and over was 56% effective in preventing hospitalization after four months.
Covid deaths and hospitalizations among people 65 and older have increased since April, according to Heather Scobie, a CDC epidemiologist who presented data during Thursday’s meeting. Deaths have increased especially among people 75 and older, Scobie said.
The CDC has shifted to a more targeted public health response with an emphasis on protecting the most vulnerable: the elderly, people with serious medical conditions and those with weak immune systems. Although there is no data on the actual effectiveness of the new boosters, the United States is moving quickly to implement them in hopes that they will protect people this fall.