A Mayo Clinic health care team examined more than 31,000 people in four states who received at least one dose of any of the vaccines – and found that their vaccines were more than 80% effective in preventing infection 36 days after the first dose. .
The vaccine’s effectiveness was 75% 15 days after the first dose and appeared 89% effective from 36 days after the second dose, according to the research, which has not yet been peer-reviewed.
More than 59 million doses of vaccines have been administered so far in the United States, according to data from the United States Centers for Disease Control and Prevention.
But Dr. Christopher Murray, director of the Institute of Metrics and Health Assessment at the University of Washington, said on Friday that the United States is unlikely to achieve collective immunity to the virus before winter.
“We know Covid is really seasonal, so when the next winter comes, we need to have a much higher level of protection to stop Covid on its tracks than we are likely to achieve,” he said.
Herd immunity does not come into effect until 80% or more of the population has immunity, either through infection or vaccination. And the new variants could complicate the picture, Murray said. If people can be reinfected with the new variants, the pandemic can take off again.
While officials hope to have the vaccines widely distributed by the end of the summer, President Biden said on Friday that issues such as weather, mutant strains and delays in manufacturing make it difficult to set a timetable.
Too risky to give single doses, Fauci says
One way to protect more people quickly, some experts suggest, is to prioritize the administration of the first doses of the vaccine.
“That would really be a problem, because if we could do that, we could vaccinate a lot more people at high risk, quickly … Everyone needs a second dose, but I think we can do it in a way that is still safe and protects much more people, “Jha told CNN’s Poppy Harlow.
But Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said on Friday that a single dose plan would be too risky.
Fauci said he was concerned that if a large number of people received a single injection and had suboptimal immune responses, they could be exposed to the virus and start incubating viral mutations. In theory, new variants may emerge, he said.
“We will continue with scientifically documented efficacy and an ideal prime response, followed by reinforcement with mRNA vaccines,” said Fauci at a briefing at the White House.
Jha, for her part, said that she agreed that everyone needed a second dose: “I think the point is, now let’s wait four weeks between the first and the second dose. And if it were six weeks or eight weeks or 10 weeks – no much more than that. “
The school can reopen regardless of the spread of the virus, says the director of the CDC
In the hope of returning to some sense of normalcy, a priority for many families and authorities has been to allow students to resume face-to-face learning.
And the director of the CDC, Dr. Rochelle Walensky, said on Friday that, given the right precautions, schools can open, no matter how many viruses are spreading in the community.
On Tuesday, the CNN analysis indicated that about 90% of children live in the so-called red zones under the guidance of the CDC – meaning that there is a high level of spread of the virus in the community. But even under these conditions, schools can reopen safely if they take precautions, Walensky said at a briefing at the White House.
The CDC said schools could reopen if they ensure that they are reducing the risk of spreading with the use of universal masks, measures to keep children and staff within two meters, frequent cleaning and disinfection and testing and contact tracking.
The CDC director’s assurances came when Fauci announced that the United States should have vaccine safety data for schoolchildren in the early fall.
The companies are just beginning testing with younger age groups, but have been testing their vaccines on young people aged 12 to 17, Fauci said in an interview with the White House. Safety data for young children is unlikely to be available until early next year, he said.
Vaccination hesitation is no excuse for inequities
Meanwhile, vaccine testing and distribution has shed light on inequalities in the medical field.
People of color have been largely underrepresented in vaccine testing in the United States for the past decade, according to a new study released Friday by researchers at the Fred Hutchinson Cancer Research Center, Harvard, Emory and other institutions.
The study found that whites made up the majority, or 78%, of participants in tests conducted between June 2011 and June 2020.
The study, published in the JAMA Network Open, comes at a time when the country is fighting a pandemic that has disproportionately affected people of color. Health leaders are working to combat mistrust of vaccines among blacks and browns, saying the injection is the key to preventing further devastation in their communities.
But this hesitation should not be an excuse for officials to explain racial disparities in vaccination, said Fauci.
“We really need to reach out to the community to have access to minority populations that they don’t have,” said Fauci in an interview with MSNBC.
CNN’s Christopher Rios, Amanda Sealy, Lauren Mascarenhas, Kevin Liptak, Maggie Fox, Nicholas Neville and Nicquel Terry Ellis contributed to this report.