观察Omicron发展趋势，Omicron引起的死亡人数在渥太华，安省，加拿大和美国都已经超过Delta。

[lindamy]

1 hr 1 min ago

Boosters provide the best protection against Omicron, large CDC studies show​

From CNN's John Bonifield and Elizabeth Cohen

A registered nurse draws up a dose of the Pfizer Covid-19 vaccine in Arlington, Massachusetts, on November 9. (Jessica Rinaldi/The Boston Globe via Getty Images)
Three new studies from the US Centers for Disease Control and Prevention highlight the importance of getting a booster shot to provide the best protection against the Omicron coronavirus variant.
This is the first real-life data to examine the effect boosters against Omicron, which now accounts for more than 99% of coronavirus cases in the United States. The studies, released Friday, raise the question of whether people with just two vaccine doses should still be considered fully vaccinated.
“I think we have to redefine fully vaccinated as three doses,” said Dr. William Schaffner, a longtime CDC vaccine adviser who was not involved with the studies.
The studies have an enormous scope, involving millions of cases, hundreds of thousands of visits to emergency departments and urgent care centers, and tens of thousands of hospitalizations among adults.
Getting boosted was 90% effective at preventing hospitalizations during a period in December and January when Omicron was the dominant variant, according to a CDC study that looked at nearly 88,000 hospitalizations across 10 states.
In comparison, getting two shots was 57% effective when it had been at least six months past the second shot.
Getting boosted was 82% effective at preventing visits to emergency rooms and urgent care centers, according to the study, which looked at more than 200,000 visits in 10 states.
In comparison, getting two shots was only 38% effective at preventing those visits when it had been at least six months past the second shot.
"I think it's the third dose that really gives you the solid, the very best protection,” Schaffner said.
That study was published Friday in the CDC’s Morbidity and Mortality Weekly Report. A second study, also published in Friday’s MMWR, concluded that people with three shots were less likely to get infected with Omicron. Looking at data from 25 state and local health departments, the CDC researchers found that among those who were boosted, there were 149 cases per 100,000 people on average each week. For those who had only two doses, it was 255 cases per 100,000 people.
A third study, to be published in the medical journal JAMA, showed that having a booster helped prevent people from becoming ill with Omicron. That study of just over 13,000 US Omicron cases found that the odds of developing a symptomatic infection were 66% lower for people who were boosted compared to those who had only received two shots.
All three studies found that unvaccinated people faced the highest risks of becoming sick with Covid-19.
The CDC currently says a person is considered fully vaccinated when they’ve received their primary Covid-19 vaccines – two weeks after receiving their second dose of an mRNA vaccine, or two weeks after their first dose of the Johnson & Johnson vaccine. Booster doses are recommended for everyone age 12 and older.
Less than half of those eligible to receive booster shots have gotten one, and only about a quarter of the total US population is fully vaccinated and boosted, according to CDC data.
Nearly 20% of the US population eligible to be vaccinated – those age 5 and older — has not received any dose of Covid-19 vaccine.

 

[lindamy]

2 hr 42 min ago

JUST IN: Pfizer and BioNTech begin clinical trial for Omicron-specific vaccine​

From CNN's Amanda Sealy

Pfizer and BioNTech have begun a clinical trial for their Omicron-specific Covid-19 vaccine candidate, they announced in a news release on Tuesday.

The study will evaluate the vaccine for safety, tolerability and the level of immune response, as both a primary series and a booster dose, in up to 1,420 healthy adults ages 18 to 55.

The study is broken up into three groups:

• Participants in the first cohort have received two doses of the current Pfizer Covid-19 vaccine at least 90 to 180 days before the study. They will receive one or two doses of the Omicron-specific vaccine.
• Participants in the second cohort have received three doses of the current Pfizer Covid-19 vaccine at least 90 to 180 days prior to the study. They will receive one dose of the current Pfizer Covid-19 vaccine or the Omicron-specific vaccine.
• Participants in the third cohort have not received any Covid-19 vaccine. They will receive three doses of the Omicron-specific vaccine.

The Omicron-specific vaccine will be administered as a 30-microgram dose, the same as the current vaccine.

"In the wake of Omicron, we are proactively investigating and manufacturing at risk an Omicron-based vaccine should it be needed, but we of course need to have results and discussions with health authorities as well as approvals before it would be deployed," a spokesperson told CNN.

Read the full story here.

 

[lindamy]

Omicron drives US deaths higher than in fall’s delta wave​

By CARLA K. JOHNSON21 minutes ago

Omicron, the highly contagious coronavirus variant sweeping across the country, is driving the daily American death toll higher than during last fall's delta wave, with deaths likely to keep rising for days or even weeks.

Omicron引起的死亡人数在渥太华，安省，加拿大和美国都已经超过Delta，这个差距加拿大比美国更加显著，应当是加拿大普遍接种疫苗比美国晚，而且比例高，对Delta波的爆发具有更有效的保护作用。​

 

[何 不]

The experiments showed that T cells elicited by vaccination or prior infection both "remain largely intact" against Omicron — but the overall magnitude of response among those who had a previous infection was lower than among those who had been vaccinated.

疫苗比自然感染还好。