A report out of South Africa offered a first glimpse at how the Omicron variant of the coronaviruses might affect people.
Experiments show that Omicron seems to dull the power of the Pfizer-BioNTech vaccine, but also show that people who have received a booster shot might be better protected.
The study found that the Omicron variant of the coronaviruses was less effective at keeping it from infecting cells than other forms of the coronaviruses.
The scientists said the results were not cause for alarm. The data suggests that people who have been vaccined may be at risk of getting infections with Omicron, which has appeared in dozens of countries around the world.
The immune response that is stimulated by vaccines is more than just antibodies. The vaccine protects against hospitalization and death from Omicron, but these experiments don't offer a complete picture.
Alex Sigal, a researcher at the Africa Health Research Institute in South Africa, said in an interview that he was not sure if the infections would translate into systems collapsing. My guess is that it will be under control.
Dr. Sigal and his colleagues worked at a rapid pace over the past two weeks to grow and test the virus. He said he would die of exhaustion if he didn't die from the virus.
Dr. Sigal was worried that vaccines might not provide any protection at all. It was possible that the Omicron variant had evolved a new way of entering cells, which would have rendered the vaccine useless. He said that all their efforts would be trash.
That was not the case.
Six people who received the Pfizer vaccine did not have Covid-19. The Pfizer vaccine had caused six other people to get infections.
The researchers found that the volunteers' antibodies were less effective against Omicron than they were against an earlier version of the coronaviruses. The level of their antibodies against Omicron was one-fortieth of what it was when tested with an earlier version of the virus. The low level of antibodies may not be enough to protect against Omicron infections.
Theodora Hatziioannou was not involved in the research but she said that number was not surprising. She said it was more or less what they expected.
Some high-profile events were caused by Omicron. At an office Christmas party in Norway, half of the 120 people who were vaccined seem to have been affected by the virus.
Dr. Sigal announced the results on the social media site.
The two sets of volunteers were different. The six people who were unvaccinated were weak against Omicron. Five out of six volunteers who had Covid-19 before they werevaccinated still produced potent responses.
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The reason for the difference is that people who have been exposed to an infectious disease produce higher levels of their own immune system.
Dr. Sigal said that the experiments will not be able to say much about how well boosters protect against Omicron until researchers can test the people who have received them. He thought that the increased level of antibodies would give good protection. He said that the more you have, the better you will be.
The new study found that booster shots were likely to help fight off the new variant.
He said he expected boosters to restore better levels of protection. Early clinical data from South Africa suggests that immunity is still effective in preventing the more severe forms of Covid-19.
Dr. Hatziioannou wasn't sure about boosters. She and her colleagues are trying to find out if the same robust protection seen in people who got vaccines after infections can be obtained from boosters. She said that she wanted to say yes, but that she had to wait.
Pfizer and Moderna have said that they would be able to produce vaccines tailored to the variant in roughly three months.
The study reinforced the need to speed up the development of O-micron-specific shots, according to Jesse Bloom. The best way to protect against Omicron is to give people a vaccine containing Omicron's genetic information, even though there is some uncertainty about how widely the variant will spread.
He said that it would merit pushing forward as fast as possible with making Omicron-specific vaccines if it could spread widely.
