Federal health officials reported Tuesday that 60 percent of Americans, including 75 percent of children, were infected with the coronavirus in February — another notable milestone in a pandemic that continues to cause turmoil expected.
The highly contagious Omicron variant was responsible for most of the damage. In December 2021, when the variant began to spread, only half of the people showed antibodies to have had a previous infection, According to new research from the Centers for Disease Control and Prevention.
While the numbers are shocking to many Americans, some scientists say they expected the number to be even higher, given the contagious variants that have raged across the country over the past two years.
Some experts say there may be good news in the data. An increase in immunity across the entire population may provide at least a partial wall against future waves. And this trend may explain why the surge that is taking place through China and many countries in Europe has been muted in the United States.
A high rate of infections in the past may also mean that there are now fewer cases of life-threatening illness or death from infection. “We’re going to see less and less severe disease, and more and more of a shift toward clinically mild disease,” said Florian Krammer, an immunologist at the Icahn School of Medicine at Mount Sinai, New York. .
He added: “It will be increasingly difficult for the virus to cause serious damage.
Regulatory officials also believe the data reinforces a new phase of the pandemic, in which infections can sometimes be common but are less harmful.
At a press conference on Tuesday, Dr Ashish Jha, the White House’s new Covid coordinator, said that containing infections “is not even a policy goal. The goal of our policy should be: to be clear, to minimize infections wherever possible, but to make sure people don’t get very sick.”
Average number of new confirmed cases per day in the US – more than 49,000 on Monday, according to the New York Times database – comparable to levels last seen at the end of Julyeven as the case has increased by more than 50 percent In the past two weeks, infectious disease specialists have tended to be due to new Omicron sub-variants.
Jha and other officials warn against complacency, and urge Americans to keep getting vaccinated and booster shots, saying antibodies from previous infections don’t guarantee protection from the virus.
According to a new study, during periods of increased Omicrons, infections increase the most in children and adolescents. Previous infections increased the least among adults 65 years of age and older, who had the highest vaccination rates and were able to take the most precautions.
Dr Kristie Clarke, researcher at the agency that led the new study, said: “The evidence for previous Covid-19 cases has increased significantly across all ages.”
The widespread contagion raises a worrying prospect: the possibility of a sustained increase in cases of Covid, a group of lingering symptoms that are not well understood.
Up to 30 percent of people infected with coronavirus may have persistent symptoms, including worrisome changes to the brain and heart. Vaccination is said to reduce the incidence of long-term Covid, although it’s not clear how much.
“The long-term effects on health care are unclear but certainly worth serious consideration, as a small fraction of the population,” said Bill Hanage, an epidemiologist at Harvard TH Chan School. will struggle with the consequences in the long run. Health.
Even a very small percentage of people who are infected or vaccinated develop Covid, which can infect millions of people across the country.
While the focus is often on preventing the healthcare system from being impacted by a spike, “we should also be concerned that our health care system will be overwhelmed.” by the ongoing health care needs of a population with long-term Covid,” said Zoë McLaren, a health policy expert at the University of Maryland, Baltimore County.
Dr. Tom Inglesby, director of the Center for Health Security at Johns Hopkins Bloomberg, said there are still tens of millions of Americans without immunity to the virus and they remain vulnerable to the short-term consequences and long-term infection. School of Public Health.
“Betting that you are in the 60s is a big gamble,” he said. “For anyone who hasn’t been immunized and boosted, I would take this new data as a direct message to get that done, or to hope that the virus has the potential to catch up to you if it hasn’t already.”
Although cases are on the rise again, especially in the Northeast, the increase in hospitalizations has been minimal, and the number of deaths is still falling. According to the agency’s most recent criteria, more than 98 percent of Americans live in low- or moderate-risk communities.
Even among those hospitalized, “we see less oxygen use, fewer ICU stays, and fortunately we haven’t seen any increase in the number of deaths related to them.” ,” said CDC director, Dr. Rochelle Walensky. “We expect that the positive trends will continue.”
The country has seen a 5-fold decrease in PCR testing for the virus since Omicron’s peak, and as a result, tracking new cases has become difficult. But the reported number is much less, about 70 times lower, Dr Walensky said, reflecting “a real and reliable drop in our overall cases.”
Omicron’s new subvariables, called BA.2 and BA.2.12.1, have replaced the previous version, BA.1, which began circulating in the country at the end of November and caused cases to skyrocket. record high in several weeks.
“Of course, even more have been infected now, because BA.2 will infect some of the people who have avoided it so far,” said Dr. Hanage.
In February, three out of four children and adolescents in the country had contracted the virus, compared with one-third of older adults, according to new research.
The fact that so many children are carrying antibodies can be comforting to parents of children 5 years of age and younger who are not eligible for immunization, as many may have obtained at least one number of immunity through infection.
But Dr. Clarke recommends that parents vaccinate eligible children as soon as regulators approve the vaccine for them, regardless of whether they have been infected before. Of children hospitalized with the virus, up to 30 percent may need intensive care, she noted.
Although many of these children also have other medical conditions, about 70% of cases of multisystem inflammatory disease, a rare consequence of Covid-19 infection, occur in otherwise healthy children.
Dr Clarke said: “As a pediatrician and a parent, I would wholeheartedly endorse vaccinating children, even if they are already infected.
Some experts say they are concerned about the long-term consequences, even in children with mild symptoms.
“Given the high rates of infection in children and adults that occurred earlier this year, I am concerned about an increase in infections,” said Akiko Iwasaki, an immunologist at Yale University who is researching the condition. increased cases of prolonged Covid disease.
To measure the percentage of the population infected with the virus, the study relies on the presence of antibodies produced in response to the infection.
CDC researchers began assessing antibody levels in people at 10 early pandemic sites, and have since extend that effort to all 50 states, the District of Columbia and Puerto Rico. Investigators used a test sensitive enough to identify people who had been previously infected for at least one to two years after exposure.
The researchers analyzed blood samples collected between September 2021 and February 2022 for antibodies against the virus, then analyzed the data by age, sex and geographic location. The investigators looked specifically at an antibody that is produced after infection but not after vaccination.
From September to December 2021, the percentage of antibodies in the samples steadily increased by one to two percentage points every four weeks. But it surged after December, up nearly 25 points in February 2022.
The proportion of samples with antibodies increased from about 45% in children 11 years of age and younger and in adolescents 12 to 17 years of age, to about 75% in both age groups.
By February 2022, about 64 percent of adults aged 18 to 49, about 50 percent of those aged 50 to 64 and about 33 percent of older adults had been infected, according to the study.
Despite the record high number of cases during the Omicron surgery, the reported statistics may not capture all infections, as some people have few or no symptoms, possibly do not choose to be tested or can test themselves at home.
According to an upcoming CDC study, there could be more than three infections for every reported case, Dr. Clarke said.
Noah Weiland Contribution report from Washington.