A research team at Imperial College in London used cell phone location data covering more than 10 million people and publicly available information on the spread of the virus to calculate which age groups were most responsible for the spread of the virus in most of the United States.
Children represent very little spread, the researchers said, as do older adults. This may mean that the opening of schools may not contribute to the spread if transmission is controlled among younger adults, they said.
“Unlike pandemic flu, these adults were responsible after the school reopened in October 2020 for about 72.2% of SARS-CoV-2 infections in the U.S. locations considered, while less than 5% originated children from 0 to 9 years old and less than 10% of teenagers from 10 to 19 years old. “
And it may be adults aged 35 to 49 who are the biggest factor in driving the pandemic, unlike younger adults, concluded Oliver Ratmann of the COVID-19 Response Team at Imperial College and his colleagues.
“Before the implementation of COVID-19 interventions, the concentrated contacts between individuals of similar age, were greater among school-age children and adolescents, and also common among children / adolescents and their parents, and middle-aged and elderly adults. at the beginning of the pandemic, these contact patterns changed substantially, “wrote the team.
“This study indicates that in places where new highly transmissible SARS-CoV-2 strains have not yet been established, additional interventions among adults aged 20-49, such as mass vaccination with transmission blocking vaccines, can bring epidemics of COVID-19 resurgents under control and avoid deaths “, they added.
They estimated that people aged 35 to 49 were responsible for 41% of new transmissions by mid-August, and adults aged 20 to 34 were responsible for another 35%. Children and adolescents accounted for only 6% of the spread. People aged 50 to 64 represent 15% of the transmission.
“Over time, the proportion of age groups among reported deaths has been remarkably constant, suggesting that young adults have probably not been the main source of epidemic resurgence since the summer of 2020 and that, instead, changes in mobility and behavior among the broadest group of adults aged 20 to 49 years underlies the resurgent COVID-19 in the U.S. in 2020, “wrote the team.
Efforts to control the spread of the virus
The researchers said that efforts to control the spread of the coronavirus – including vaccination – should probably focus on people aged 20 to 49 years.
But there is still not enough vaccine to immunize everyone, and the federal government is working with state and local governments to try to vaccinate people in an orderly, fair and logical manner.
Current guidelines from the US Centers for Disease Control and Prevention put health care professionals on the front lines and fragile residents of long-term care facilities at the front of the vaccine line. The White House, under Presidents Trump and Biden, suggested that states open vaccination for anyone over 65, as this age group is considered most vulnerable to Covid-19’s death and serious illnesses.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said on Tuesday that although older people are at higher risk for serious illnesses, experts have long suspected that younger people are causing the spread of the disease. virus in the United States.
Fauci did not dismiss the idea that the United States should ensure that people aged 20 to 49 are vaccinated, but noted that this should not happen at the expense of vaccinating older people, especially those with underlying health problems.
“You don’t want to deprive them to get the youngest, because they are the ones who will end up in the hospital and have a higher mortality rate,” Fauci told Don Lemon of CNN. “What we don’t want to do is neglect them.”
Dr. Jonathan Reiner, professor of medicine at George Washington University and medical analyst at CNN, said that while it is important to vaccinate older people, younger adults should not necessarily be behind the line.
“I thought for a while now that the priority groups are just not working and that we have to open them up for everyone,” Reiner told CNN’s Jake Tapper on Wednesday.
“We can now reserve, perhaps, a higher percentage of vaccines for older Americans, but I think we need to start distributing the vaccine to younger people for exactly this reason – the youngest are the people who spread the virus,” Reiner added.
The Moderna and Pfizer Covid-19 vaccines currently available in the United States provide protection against serious illnesses, although it is not clear whether they prevent transmission of the virus.
The researchers suggested that the type of protection provided by vaccines may play a role in deciding who should get the vaccine and when.
“Ultimately, everyone has to be vaccinated,” said Reiner. “And if you end up vaccinating older people, it will save their lives because they are at greater risk. And if you vaccinate younger people, it will also save lives because they are spreading the virus ”.