A split Food and Drug Administration voted Tuesday to recommend including an omicron-fighting component in updated Covid boosters this fall. But vaccine stocks tumbled.
The Vaccines and Related Biological Products Advisory Committee voted 19-2 in support of omicron-targeted booster shots. This puts the FDA on the path to authorizing updated vaccines in time for a potential seasonal Covid surge in the fall.
But plenty of questions remain. Pfizer (PFE), Moderna (MRNA) and Novavax (NVAX) tested several boosters, including shots that target omicron alone and bivalent injections. The latter target omicron plus the ancestral strain of Covid. Complicating matters, omicron has its own sub-variants.
On Tuesday, the Centers for Disease Control and Prevention said two of those — known as B.A.4 and B.A.5 — make up a combined 52% of U.S. cases. The problem is, vaccine makers haven’t had a chance to test vaccines targeting those omicron spinoffs. Their updated shots target the earlier B.A.1 cousin.
It’s impossible to exactly pinpoint which variant will be dominant in the fall, Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said during the meeting.
“What we’re doing today is working on a very challenging area because none of us has a crystal ball,” he said. “Were trying to use every last ounce of what we can from predictive modeling and from the data we have that’s emerging to try to get ahead of a virus that’s been very crafty. For someone that’s only nanometers in size, it’s been pretty darn crafty.”
Vaccine Stocks Tackle Omicron
But in after-hours trading on today’s stock market, vaccine stocks were relatively muted, moving less than 1% in either direction. During the regular session, shares toppled.
Pfizer stock lost 2.4%, ending the day at 50.66. Shares of its partner, BioNTech (BNTX), tumbled 2.7% to 139.82. Moderna stock skidded 2.2% to 142.19. Novavax stock fell 5.1% to 51.06.
The matter now heads to the full FDA. The agency isn’t bound by the panel’s recommendation, but it often follows the advice. If successful at the FDA, the omicron vaccine matter will head to the CDC.
Two panelists voted against recommending an omicron update. Drs. Paul Offit and Henry Bernstein. Neither offered an explanation following the vote. However, prior to the vote Bernstein noted data are still limited for boosters targeting B.A.4 and B.A.5. And Offit said he was uncomfortable with the level of protection the omicron boosters have.
In recent testing, Pfizer said its omicron booster led to a 13.5-19.6 fold increase in antibodies capable of blocking omicron and its spinoffs. A bivalent vaccine — which could target omicron and the first strain — generated a 9.1-10.9 fold increase in antibodies, depending on the dosage. The vaccine stock inched a fraction higher on Monday following its booster news.
Moderna Tests Bivalent Vaccine
Similarly, Moderna tested a bivalent vaccine that includes an omicron-fighting component. It resulted in a 5.4-fold increase in antibodies capable of handling the B.A.4 and B.A.5 sub-variants of omicron.
In people previously infected with Covid, it led to a 6.3-fold increase. Officials currently expect those specific sub-variants to soon dominate Covid cases in the U.S.
Novavax doesn’t yet have authorization for a primary Covid series in the U.S. Nevertheless, the biotech is still testing an omicron booster as well as a bivalent booster that contains an omicron-fighting component. In testing, both options led to “high levels” of effectiveness, the company said in briefing documents.
Dr. Amanda Cohn, another panelist, said the recommendation doesn’t necessarily mean boosters will be suggested for everyone in the fall. But the vote is an important step toward authorization. Panelist Dr. Arthur Reingold made a similar assessment.
“Who gets what and when?” he asked.
Panelist Dr. Wayne Marasco also questioned the ultimate effectiveness of the messenger RNA vaccines from Pfizer and Moderna. Novavax’s Covid vaccine, on the other hand, uses a different technology based on proteins.
“We can do better and I’m not sure the mRNA vaccines are giving us the best kind of immunity we can get here,” he said during the discussion.
Taking Care Of The Kids
Another important piece for the vaccine stocks: children. The FDA is only a week out from signing off on primary shots for children under the age of 5. There are little data in the pediatric population. That fact is unacceptable, panelist Dr. Archana Chatterjee said.
“The pediatric studies need to be done and they need to be done now,” she said.
Similarly, panelist Dr. Michael Nelson said immuno-bridging — a process that infers effectiveness of a vaccine under different circumstances — wouldn’t be sufficient for children. Because boys and young men are susceptible for heart inflammation following vaccination, dose response and safety studies should be completed in young children, he argued.
He worried about young children “always being behind the power curve in receiving vaccines.”
Panelist Dr. Cody Meissner also suggested repeated booster doses could ultimately lead to mounting side effects. He suggested the matter could be particularly tricky in children.
A Moderna representative said the company expects to have updated data from its omicron shots — an injection focused solely on omicron and a bivalent containing an omicron-fighting component — in babies and young children in October or November. However, these shots target B.A.1, not the more dominant B.A.4 and B.A.5 sub-variants.
Follow Allison Gatlin on Twitter at @IBD_AGatlin.
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