Coronavirus infects more than half of Americans, the CDC reports

Federal health officials reported Tuesday that 60% of Americans, including 75% of children, had been infected with the coronavirus by February. This is another notable milestone in the pandemic and continues to confuse expectations.

Highly contagious variants of Omicron accounted for the majority of the victims. In December 2021, when the subspecies began to spread, only half had antibodies that indicated a previous infection. According to new research From the Centers for Disease Control and Prevention.

The numbers shocked many Americans, but some scientists said they expected the numbers to be even higher given the infectious variants that marched nationwide over the past two years.

According to some experts, the data may have good news. Improving the immunity of the entire population may provide at least a partial breakwater for future waves. And this trend may explain why the surge that is currently booming in many countries in China and Europe is silent in the United States.

A higher proportion of previous infections may also mean that there are fewer cases of life-threatening illnesses and deaths compared to infections. Florian Kramer, an immunoscientist at Mount Sinai School of Medicine in New York, said:

“It will be more and more difficult for the virus to cause serious damage,” he added.

Government officials also believe that the data is taking a new step in the pandemic. At this stage, infections can sometimes be common, but less harmful.

At a press conference on Tuesday, Dr. Ashishger, the new White House coordinator, said stopping the infection was “not even a policy goal.” Obviously, the goal of our policy is to minimize infection as much as possible, but to prevent people from getting serious illness. “

Mean number of new cases per day confirmed in the United States (more than 49,000 as of Monday), according to the New York Times database. Comparable to the last level seen in late JulyIn some cases Increased by more than 50 percent Over the past two weeks, infectious disease experts have attributed it to a new Omicron submutant.

Dr. Ja and other officials warned of complacency and urged Americans to continue receiving vaccinations and booster shots, saying that antibodies from previous infections did not guarantee protection from the virus.

According to a new study, during the Omicron surge, infections increased most rapidly between children and adolescents. Adults over the age of 65, who had the highest immunization rates and were most likely to take preventive measures, had the least pre-increased infections.

“Evidence of previous Covid-19 infections has increased significantly in all age groups,” agency researcher Dr. Christie Clark, who led the new study, said at a press conference on Tuesday.

Widespread infections cause annoying prospects: potential increases in the case of long Covids, poorly understood constellations of protracted symptoms.

Up to 30% of people infected with the coronavirus can have persistent symptoms, such as anxious changes in the brain or heart. Vaccination is believed to reduce the probability of long Covids. I’m not sure How much.

Bill Hanage, an epidemiologist at Harvard TH Chan Public School, said: health.

Even a very small proportion of infected or vaccinated people who develop Covid represent millions nationwide.

Often the focus is on preventing the collapse of the healthcare system due to the surge, but we also need to be concerned that our healthcare system will be overwhelmed by the ongoing health needs of people with long Covids. There is, “says Zoë McLaren. Health policy expert at the University of Maryland, Baltimore County.

Dr. Tom Inglesby, director of the Johns Hopkins Bloomberg Health Security Center, said that tens of millions of Americans are still vulnerable to both short-term and long-term consequences of the infection, with tens of millions of Americans not immune to the virus. He said he would remain as it is. Faculty of Public Health.

“Beting that you are at 60 percent is a big bet,” he said. “For those who have not been vaccinated or boosted, I take this new data as a direct message and either do it or expect the virus to catch up if it hasn’t caught up yet. To do.”

Especially in the northeast, the number of cases is on the rise again, but the increase in hospitalizations is negligible and the number of deaths is still declining. According to the latest agency standards, over 98 percent of Americans live in low- or medium-level risk communities.

Dr. Rochelle Walensky, director of the CDC, said, “Lower oxygen use, lower ICU stays, and fortunately, increased deaths associated with them,” even among hospitalized people. I didn’t. ” “I hope the positive trend will continue.”

In this country, PCR testing for the virus has been reduced by about one-fifth since the peak of Omicron, making it difficult to track new cases. However, the reported numbers are much lower, about one-70th, Dr. Warensky said, reflecting “a true credible decline in our overall case.”

A new subvariant of Omicron, called BA.2 and BA.2.12.1, began to prevail in the country in late November and is a repeat before sending cases that surged to record highs within a few weeks. Replaced by .1.

“Of course, BA.2 will infect those who have previously avoided it, so more people are now infected,” said Dr. Hanage.

By February, three out of four children and adolescents in the country were already infected with the virus, while one-third of the elderly were infected with the virus, according to a new study.

The fact that so many children have antibodies is comfortable for parents under the age of 5 who are not eligible for vaccination, as many children may have acquired at least some immunity from the infection. May be provided.

However, Dr. Clark urged parents to immunize qualified children as soon as regulatory authorities approve the vaccine, regardless of previous infections. Among children hospitalized with the virus, she said, up to 30 percent may require intensive care.

Although many of those children also have other medical conditions, about 70% of cases of multisystem inflammatory disease, which is a rare result of Covid-19 infection, occur in otherwise healthy children. increase.

“As a pediatrician and parent, I absolutely support children to be vaccinated, even if they are infected,” said Dr. Clark.

Some experts said that even children with mild symptoms are concerned about long-term effects.

“Given the very high prevalence of child and adult infections earlier this year, I’m worried that there will be more long Covid cases,” said Yale University’s immunity studying this condition. Akiko Iwasaki, a scholar, said.

To measure the proportion of the population infected with the virus, this study relied on the presence of antibodies produced in response to the infection.

CDC researchers began assessing antibody levels in 10 people early in the pandemic. Expanded that effort All 50 states, in District of Columbia and Puerto Rico. Investigators used a sensitivity test sufficient to identify previously infected people for at least 1-2 years after exposure.

Researchers analyzed blood samples collected from September 2021 to February 2022 to look for antibodies to the virus and analyzed data by age, gender, and geographic location. Researchers specifically looked for the types of antibodies that were produced after infection, not after vaccination.

Between September and December 2021, the prevalence of antibodies in the sample increased steadily by 1-2 percentage points every 4 weeks. However, it surged after December and increased by nearly 25 points by February 2022.

The proportion of samples containing antibodies increased from about 45% in children under 11 years and adolescents aged 12 to 17 to about 75% in both age groups.

By February 2022, about 64% of adults aged 18-49, about 50% of adults aged 50-64, and about 33% of the elderly were infected, according to the survey.

Despite record high cases during Omicron surge, reported statistics may not capture all infections. You may have few or no symptoms, did not choose a test, or you may have tested it yourself at home.

According to a future CDC study, Dr. Clark said there could be more than one infection in each reported case.

Noah Wayland Contributed to the report from Washington.