A fourth dose of Pfizer and BioNTech's Covid shot is only partially effective against omicron, according to an Israeli study released Tuesday that sent the vaccine stocks diving.
The test was conducted at the Sheba Medical Center and involved 154 medical staff members. Vaccine recipients showed an increase in virus-blocking antibodies. Still, there were "a lot of infections" in that group, said Gili Regev-Yochay, a lead researcher in the study.
"The bottom line is that the vaccine is excellent against the alpha and delta (variants), for omicron it's not good enough," she said, according to the Times of Israel.
On today's stock market, both vaccine stocks toppled. Pfizer stock lost 1.5% and ended the regular session at 54.11. BioNTech stock dropped 13.7% to 169.23.
Vaccine Stocks: A New Challenge In Covid
The challenge for vaccine stocks is in how omicron evolved. The strain contains mutations to the spike protein, a protrusion on the outside of the virus. Antibodies that arise from vaccination — and earlier infections — no longer recognize the mutated protein. As a result, the antibodies can't effectively lock onto the protein, preventing the virus from replicating.
The hospital didn't provide more specific information. Regev-Yochay suggested giving a fourth shot to higher-risk people, including the elderly. The news could limit the financial opportunity for the vaccine stocks working on boosters.
Meanwhile, the current omicron wave is showing signs of having peaked in the U.S., CNBC reported. The U.S. has reported a daily average of nearly 800,000 cases over the past week. That's well above the last winter surge. But a handful of states and cities appear to have hit plateaus or fallen in recent days.
Vaccine stocks Pfizer and BioNTech are working on an omicron-specific shot. U.S. health officials still say it might not be necessary. Pfizer says the variant-specific booster will be ready in March. It will still have to pass muster with regulators before launching.
Follow Allison Gatlin on Twitter at @IBD_AGatlin.
