The company’s finding is based on only a small study of blood samples in a laboratory, but others are sure to follow.
Pfizer and BioNTech said Wednesday that laboratory tests suggest a booster shot of their coronavirus vaccine offers significant protection against the fast-spreading Omicron variant of the virus. The companies said that tests of blood from people who had received only two doses found much lower levels of antibodies protecting against Omicron than against an earlier version of the virus. That suggests that two doses “may not be sufficient to protect against infection” by the new variant, the companies said. While limited in scope — to get fast results, the companies examined only about 39 samples — the findings provided a bit of hopeful news at a time of renewed uncertainty. Health departments are identifying close to 100,000 cases a day, hospitalizations are ticking up and deaths are again on the rise in the United States, almost all due to the Delta variant. The companies summarized their findings in a news release and did not release any data. Their study came on the heels of a preliminary report on laboratory experiments in South Africa that also found Omicron seemed to dull the power of two doses of the Pfizer vaccine. The Omicron variant has been detected in about 20 American states so far, with cases rising much faster in parts of South Africa and Europe. Early modeling and analysis suggest that it may move twice as fast as Delta. In South Africa, where Omicron already appears to be dominant, two large hospitals are reporting more children testing positive for the coronavirus after being admitted for other reasons, suggesting increased community transmission there. Around the world, cities are canceling Christmas and New Year’s Eve events amid unresolved questions about the transmissibility and virulence of the new variant. President Biden went out of his way to draw attention to Pfizer-BioNTech’s findings on Wednesday, calling them “very, very encouraging” and saying they showed that the vaccines remain a bulwark against the virus. “If you get the booster, you’re really in good shape,” Mr. Biden said. According to federal data, the United States has more than 200 million fully vaccinated people, but only about 50 million have gotten a booster dose. But Pfizer-BioNTech’s study of blood samples in a laboratory is not proof of how the vaccines will perform in the real world. While antibodies are the first line of defense against infection, they are only part of a wider-ranging and powerful response by the immune system. Because antibodies are the fastest and easiest part to measure, those results typically come first. “You have to start somewhere,” said Kathrin U. Jansen, a senior vice president and the head of vaccine research and development at Pfizer, while awaiting the results of more complex studies and “real-world evidence that tells you what we need to know.
