A landmark Israeli trial is expected to show that four shots of vaccine didn't stop the Omicron variant.
The extra dose of Pfizer of Moderna vaccine seemed to have some effect, but the rates of infections in the study were not different to those who had three doses of Pfizer.
According to The Times of Israel, Gili Regev-Yochay, a lead investigator on the study, told reporters that the vaccine was good against Alpha and Delta, but not good enough for Omicron.
The results of the trial are preliminary, so the investigator did not release data. She said she shared the findings because there was a large public interest.
If the findings are confirmed, it will bolster calls for a new version of the COVID-19 vaccine. Some vaccines are in the early stages of development.
The Sheba Medical Center launched a trial a month ago that is looking at the effect of Pfizer and Moderna on 154 people.
There was an increase in the number of people who got the fourth shot.
Many people who received the fourth dose of Omicron have been diagnosed with Omicron. The Times of Israel said that it was a bit less than the control group, but still a lot of infections.
The people who were in the control group had three doses of the Pfizer vaccine.
The Times of Israel reported on Sunday that 500,000 fourth shots of vaccine had been given in Israel.
Vaccines are still effective against disease.
The second shot of the vaccine reduced the risk of hospitalization by over 70% within 24 weeks, according to figures published by the UK health security agency.
A third shot boosted the protection back up, reducing the risk of hospitalization by at least two weeks.
Scientists hoped that the increased levels of antibodies after a booster shot would mean that the body would be able to ward off infections.
Lab studies have shown that the Omicron variant is very good at evading the antibodies that block previous coronaviruses.
"We know by now that the level of antibodies needed to protect is too high for the vaccine, even if it's a good vaccine," said Regev-Yochay.
Israel, which has already given a third shot of vaccine to more than 45% of its people, has seen a surge in cases driven by Omicron.
There were trends in deaths and cases in Israel as of January 16.
Data is our world.
The graph of their Omicron wave infections isn't encouraging vs with 3rd booster, according to Eric Topol.