The Pfizer vaccine decreases the risk of hospitalization with the Omicron variant by 70%, according to new South African data. But the risk of infection is only reduced by 33%, which makes the experts consulted by Press that hospitals will be overcrowded again. Their position on the third dose of vaccine has also changed dramatically, which suggests a return to mass vaccination like last summer.
“The vaccine machine is not at the speed that would be desired,” explains Gaston De Serres, epidemiologist at the National Institute of Public Health of Quebec (INSPQ). “We need vaccinators like in the summer, Minister Dubé said today. The third doses should be given as soon as possible, not in February. In early December, an Australian study published on MedRxiv showed that in a test tube, a third dose of Pfizer vaccine improved the immune response to the Omicron variant.
The Omicron variant is “Formula 1” in the ability to infect, according to Dr From Serres.
It is a terribly contagious virus. It will be necessary to review the measures put in place to slow down transmission.
Gaston De Serres, epidemiologist at the INSPQ
The rate of protection against hospitalization for the Delta variant is over 90% and over 75% for infection, according to the latest data from the INSPQ.
The South African data has been published in broad outline by the country’s largest medical insurer, Discovery Health, and the South African Medical Research Council, but not as a scientific prepublication. “We spoke to the Committee on Immunization this morning, we could not get the study,” said Andrés Finzi, immunologist at the University of Montreal. The study stems from 78,000 infections with the Omicron variant, but it is not known what the proportion of hospitalizations was, deplore Mr Finzi and the Dr From Serres.
Quebec lagging behind
In Canada, 2.8 million people have received a third dose of the vaccine, but in Quebec, the total is less than 450,000 people. Should we have been more proactive? “To the relief of those who are in charge of the vaccination system, two weeks ago, the fire was not caught in the cabin, as it could happen when Omicron sets off in Quebec,” says Dr.r From Serres. He emphasizes that the last evaluations of vaccine protection, in November, were very good because the longer time between the first two doses in Quebec ensured better efficacy than elsewhere in the world.
Mr. Finzi is currently performing analyzes of the reaction of the immune system of people vaccinated in Quebec, on the basis of blood samples, to see how he will react to Omicron. “We should know more next week,” says the Montreal immunologist.
Could the lower severity of the Omicron variant infection, suggested by some preliminary studies, compensate for its greater contagion? Last week, a Center for Disease Control and Prevention (CDC) study of 50 Omicron variant infections reported a hospitalization rate of 2%, among largely vaccinated patients, sometimes even three. time. Among the unvaccinated in Quebec, the hospitalization rate is 1.7% for 18-29 year olds and 3.4% for 30-30 year olds, notes the Dr From Serres. “But even if we had two to three times as many hospitalizations, if we have 20 times as many cases, that doesn’t help. ”
44%: proportion of those over 65 who had received three doses of the vaccine in the United States by November 19
Source: CDC
Promising Pfizer drug
Pfizer confirmed on Tuesday that its anti-COVID-19 pill reduced hospitalizations and deaths among those at risk by nearly 90% when taken in the first few days after symptoms appeared, according to clinical trials. No deaths were recorded among those who received the treatment. Participants were unvaccinated and at high risk of developing a severe case of COVID-19. Pfizer also announced that its antiviral treatment, which will be marketed as Paxlovid, is expected to remain effective against the Omicron variant.
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“New rhythm”
More than 75 countries have reported cases of the Omicron variant, and it is likely to be found in even more countries, World Health Organization (WHO) director-general Tedros Adhanom Ghebreyesus told a press conference. “Omicron is spreading at a rate that we have never seen with any other variant” and should replace Delta, even as the latter is responsible for cases that plague many countries, according to the head of the WHO.
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