Vaccines and booster shots offer superior protection from the Delta and Omicron variants, according to three new studies released by the Centers for Disease Control and Prevention.
The data back up earlier findings supporting booster shots and offer the first comprehensive insight into how vaccines fare against the Omicron variant. In one of the studies published Friday, a CDC analysis found that a third dose of either the vaccine from Pfizer Inc.
and BioNTech SE or Moderna Inc.
was at least 90% effective against preventing hospitalization from Covid-19 during both the Delta and Omicron periods.
During the Delta period, vaccine effectiveness against hospitalization from Covid-19 was 90% from two weeks until about 6 months after dose two, 81% from at least six months after dose two and 94% at least two weeks after a booster dose. When Omicron was dominant, vaccine effectiveness against hospitalization for the same periods were 81%, 57% and 90%, respectively.
“Those who remain unvaccinated are at significantly higher risk for infection and severe Covid-19 disease,” CDC Director Rochelle Walensky said. “Protection against infection and hospitalization with the Omicron variant is highest for those who are up to date with their vaccination, meaning those who are boosted when they are eligible.”
An additional study published in Nature Thursday also supports booster doses, and backs up previous findings from Pfizer and BioNTech showing that a third dose of their Covid-19 vaccine neutralizes Omicron but its two-dose regimen is significantly less effective at blocking the virus.
According to the study published Thursday, two doses of the Pfizer-BioNTech vaccine provided little neutralizing antibody immunity against Omicron infection even at one month after vaccination, but a third dose offered more than 50% protection against Covid-19.
Separate research the CDC published on Wednesday showed that among patients in California and New York during the Delta wave, prior infection provided more protection against Covid-19 than vaccination, though both offered significant defense from the virus. The data was collected before Omicron’s emergence and the widespread booster campaign, so many people were likely experiencing some degree of waning immunity from vaccination. The CDC said the findings couldn’t be applied to the Omicron wave.
The agency also said in that report that vaccination was the safest way to acquire immunity against the virus because contracting Covid-19 carries the risk of serious illness or death, even among people at lower risk.
The Food and Drug Administration approved Gilead Sciences Inc.’s
The antiviral drug remdesivir for people with mild-to-moderate Covid-19 symptoms who are at high risk of developing severe cases. The drug, known by the brand name Veklury, was first approved in 2020 to treat people hospitalized with Covid-19.
The FDA said the approval was based on a study showing that 0.7% of patients taking remdesivir required hospitalization, compared with 5.3% of subjects who received placebos. Remdesivir isnt as convenient as other treatments because it requires three days of intravenous infusions.
Some two months since Omicron began its rapid spread around the world after being identified in Africa, pressure on hospitals in southern areas of the US battered early by the variant’s spread has started to ease, while France became the second big European economy to set out plans to begin lifting Covid-19 restrictions.
Many hospitals in places like New York and Washington, DC, are reporting fewer Covid-19 patients and smaller numbers of staff absent with infection.
New admissions in the Northeast, where Omicron exploded after its first US detection in early December, appear to have been on the decline for at least a week, data from the US Department of Health and Human Services show. Nationally, the Omicron wave has yet to peak, and hospitals around the country remain under significant strain from Covid-19 patient counts that are still at record levels.
Nationally, the seven-day average for new, confirmed Covid-19 admissions appears to have at least leveled off, according to the HHS data. But hospitals in some parts of the US are still facing the worst of the Omicron surge.
In Oklahoma, four systems warned Monday that they are at the breaking point as their emergency departments overflow. By Monday, there were 107 patients in the Oklahoma City-area emergency rooms waiting for open inpatient or intensive-care beds, the hospitals said.
Hospital officials say they are seeing significant differences in Omicron-era cases based on a patient’s vaccination status. In Oklahoma, which has below-average vaccination rates, Kersey Winfree, the regional chief medical officer for SSM Health Oklahoma, one of the hospital operators, said about 80% of the Covid-19 patients requiring acute care are unvaccinated. “The vaccinated people that are affected by this are having a much better experience,” he said.
Nationally, the seven-day average for new daily cases—reporting of which has been affected recently by state and holiday-related reporting disruptions—was about 736,000 on Thursday, data from Johns Hopkins University show. Case counts have recently tripled the pre-Omicron record reached a year ago.
Seven-day averages in states like New York, New Jersey and Connecticut are showing sharp declines from recent Omicron-fueled peaks, Johns Hopkins data show.
In France too, the Omicron wave is receding in parts of the country hit first by the variant, including Paris, and the government is planning to begin lifting some of its Covid-19 restrictions beginning next month.
As of Feb. 2, the country plans to lift requirements, including the obligation to wear masks in the street and for most office workers to work from home at least three days a week, French Prime Minister Jean Castex said. In mid-February, nightclubs will be able to reopen and people will be allowed to drink and eat on public transportation, he added.
While infections are dropping in Paris, they remain at a high level, with 3.4% of the city population testing positive in the seven days ending Jan. 17. And at a national level, infections are continuing to rise, with 3.2% of people testing positive in the same period, compared with 2.9% of people in the seven previous days ending Jan. 10.
Despite the large numbers of infections, the number of people entering intensive care has been declining for more than a week, with the seven-day rolling average of new life-support admissions down 14% from a week earlier.
The UK, which was the first European country hit by Omicron, has led the way in lifting Covid-19 restrictions, with cases and hospitalizations in decline across the country. The government has removed its recommendation to work from home if possible and no longer requires face masks in shops and classrooms. Proof of vaccination or a negative Covid-19 test will no longer be needed from next week to enter nightclubs and other large venues in England.
—Renée Onque contributed to this article.
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