A woman receives a booster dose of the Moderna coronavirus (COVID-19) vaccine at a vaccination center in Antwerp, Belgium, February 1, 2022.
Johanna Geron | Reuters
The independent panel of advisers to the US Food and Drug Administration on Thursday recommended those updated Covid shots for fall and winter focus on one of the XBB variants, which are now the dominant strains of the virus across the country.
The Commission voted unanimously that the new jabs should be monovalent – meaning they are designed to protect against one variant of Covid – and target a member of the XBB family.
Those tensions of Covid are descendants of the omicron variant, which caused cases to rise to record levels early last year. They are among the most immune-evasive species to date.
Advisors also generally agreed that the new shots should specifically target a variant called XBB.1.5. The panel only discussed that specific species selection and did not vote on the matter.
XBB.1.5 accounted for nearly 40% of all Covid cases in the US in early June, according to facts of the Centers for Disease Control and Prevention. That share is slowly declining, and cases of the related XBB.1.16 and XBB.2.3 variants are on the rise.
Advisors noted that XBB.1.5 seems most ideal for the fall, as vaccine makers Pfizer, Moderna and Novavax have already started developing jabs targeting the strain.
“The 1.5 looks good. It seems the most feasible thing to do is cross the finish line early without causing delays and availability,” said Dr. Melinda Wharton, a senior official with the National Center for Immunization and Respiratory Diseases. “The vaccine we can use is the vaccine we can get. And so it feels like this would be a good choice.”
The FDA generally follows the advice of its advisory committees, but is not required to do so. It is unclear when the agency will make a final decision on species selection.
There is also uncertainty about which age groups the FDA and the GGD have will advise getting the updated photos this fall.
But the panel’s recommendation is already a win for Pfizer, Moderna and Novavax – all of whom have conducted early trials on their respective XBB.1.5 shots ahead of the meeting.
“Novavax expects to be ready for commercial delivery of a protein-based monovalent XBB COVID vaccine this fall in line with current [advisory committee] recommendation,” said John Jacobs, the company’s president and CEO.
The US is expected to shift vaccine distribution to the private sector this fall. That means the vaccine makers will start selling their new Covid products directly to healthcare providers and compete for commercial market share.
The panel’s recommendation coincides with a broader shift in how the pandemic is affecting the country and the world at large.
Having Covid cases and deaths dropped to new lows, governments have rolled back strict health mandates such as masking and social distancing, and many people believe this is the case pandemic is over all together.
But dr. Peter Marks, head of the FDA’s vaccine division, said the agency is concerned the US will have another Covid surge “at a time when the virus has continued to evolve, the immunity of the population has continued to decline and we going in for the winter. .”
Updated Covid vaccines that are updated periodically to target a high-circulating variant will restore protective immunity against the virus, said Dr. David Kaslow, a senior official in the FDA’s vaccine division.
It’s a similar approach to how the species are selected for the annual flu shot. Researchers are assessing the strains of the virus in circulation and estimating which ones will be most prevalent in the coming fall and winter.
But it’s unclear how many Americans will roll up their sleeves later this year to get the updated photos.
Only about 17% of the US population According to the CDC, about 56 million people have received the boosters from Pfizer and Moderna since they were approved in September.
More than 40% of adults age 65 and older have received a boost with those injections, while the percentage among younger adults and children varies between 18% and 20%.
Those boosters were bivalent, meaning they targeted the original strain of Covid and the omicron subvariants BA.4 and BA.5.
Pfizer, Moderna and Novavax shot data
At the meeting, Pfizer, Moderna and Novavax presented preliminary data on updated versions of their shots designed to target XBB variants.
Moderna has evaluated shots targeting XBB.1.5 and XBB.1.16 — another transmissible omicron lineage, according to Rituparna Das, the company’s vice president of Covid vaccines.
Data from preclinical studies in mice suggest that a monovalent vaccine targeting XBB.1.5 produces a more robust immune response against the currently circulating XBB variants than the authorized bivalent vaccine targeting BA.4 and BA.5, Das said.
She added that clinical trial data from more than 100 people similarly show that the monovalent XBB.1.5 vaccine produces protective antibodies against all XBB variants. All trial participants had previously received four doses of Covid vaccine.
Das said extensive protection against XBB strains is likely due to the fewer unique mutations between the variants, meaning their makeup is similar.
According to Darin Edwards, the leader of Moderna’s Covid vaccine program, there are only three unique mutations between the XBB.1.5 and XBB.1.16 variants. In comparison, there are 28 mutations between omicron BA.4 and BA.5.
That means the immune response an updated shot produces against XBB variants will likely be similar, regardless of which specific variant it targets, Edwards said.
Pfizer also presented early trial data indicating that a monovalent vaccine targeting an XBB variant provides enhanced immune responses against the XBB family.
The company provided specific timelines for delivering an updated vaccine, depending on the strain the FDA selects.
According to Kena Swanson, the company’s senior chief scientist, Pfizer will be able to deliver a monovalent shot targeting XBB.1.5 by July and a punch targeting XBB.1.16 by August.
Pfizer can’t hand out another shot until October if the FDA chooses a completely different strain, Swanson said.
Novavax gave no specific timeline for delivering a shot targeting XBB.1.5, but noted that an XBB.1.16 shot would take eight weeks longer.
Novavax revealed preclinical study data indicating that monovalent vaccines targeting XBB.1.5 and XBB.1.16 induce higher immune responses to XBB subvariants than bivalent vaccines.
Data also shows that an XBB.1.5 injection produces antibodies that prevent XBB.2.3 from binding to and infecting human cells, according to Dr. Filip Dubovsky, Novavax’s medical director.
Dubovsky said the trial results support the use of a monovalent XBB.1.5 shot in the fall.
Novavax’s jab used protein-based technology, a decades-old method of fighting viruses used in routine vaccinations against hepatitis B and shingles.
The vaccine works differently than the messenger RNA vaccines from Pfizer and Moderna, but achieves the same result: teaching your body how to fight Covid.