Science & Technology

One in three Americans will be infected with COVID-19 in 2020, the study says

One in three Americans will be infected with COVID-19 in 2020, the study says

Undocumented case consisting of about three-quarters of infection

New research published in the journal Nature By the end of 2020, it is estimated that 103 million Americans, or 31% of the US population, will be infected with COVID-19. Researchers at Columbia University have modeled the epidemic of the coronavirus and found that it is less than a quarter of the infection, or only 22 people. Percentage-explained in cases identified through test-based public health reports.

This is the first study to comprehensively quantify the overall burden and characteristics of COVID-19 in the United States in 2020. Researchers used population, mobility, and confirmed case data to simulate the transmission of SARS-CoV-2 within and between all 3,142 counties in the United States.

“The majority of infectious diseases were not explained by the number of confirmed cases,” said Jeffrey Shaman, a professor at the Mailman School of Public Health at the Institute for Humanity and Nature. “These undocumented cases are often mild or asymptomatic infectious and allow the virus to spread rapidly to a wider population.”

The study found that infectious diseases were more prevalent in some parts of the country. In the Midwest and upper Mississippi Valley areas, including Dakotas, Minnesota, Wisconsin, and Iowa, it was estimated that more than 60% of the population was infected by the end of 2020. In the same time frame, 52 percent of Chicago residents, 52 percent of Los Angeles, 42 percent of Miami, 44 percent of New York City, and 27 percent of Phoenix people were infected.

Over time, more tests were done in areas of increased infection, but they still gave an incomplete picture, the researchers said. The portion of confirmed cases reflected in the survey estimates increased from 11% in March to 25% in December. This reflects increased test competence, relaxation of initial restrictions on the use of tests, and increased awareness, concern, and care pursuit among the general public. However, individuals with mild or asymptomatic infections that could spread the virus were less likely to be tested, so detection rates were well below 100%.

The study also found that on December 31, 2020, about 1 in 130 Americans (0.77 percent) were infected with the virus. A similar proportion (0.83 percent) was estimated to be infected, but not yet transmitted. However, in some metropolitan areas, the proportion of individuals infected at the end of the year was much higher.

Case fatality was reduced by increased treatment and public health measures. The proportion of infectious disease patients who died of COVID-19 decreased from 0.8% in the spring wave to 0.3% by the end of the year. Urban areas such as New York City, which peaked in the spring, have seen the worst numbers due to delays in availability testing and masking of mandates, overwhelming hospitals, and lack of effective treatments. I did.

Different cities peaked at different times of the year. New York and Chicago experienced strong spring and autumn / winter waves, but were less active during the summer. Los Angeles and Phoenix were hit by summer and autumn / winter waves. And Miami experienced all three waves. Los Angeles County, the largest county in the United States with a population of over 10 million, was hit particularly hard in the fall and winter, with a regional infection rate of 2.4% on 31 December.

Looking to the future, the authors write that several factors will change the population’s susceptibility to infection. The virus continues to spread to people who have not yet been infected. Vaccines protect against serious and deadly illnesses, but breakthrough infections, including mild or asymptomatic ones, contribute to the spread of the virus. This study provides evidence that antibodies can decline over time, and while some people are definitely re-infected, for possible reinfections among those who are already ill. Not explained. Newer, more contagious variants will increase the likelihood of reinfection and breakthrough infections, the authors write.

SenPei, an assistant professor of environmental health sciences at Mailman, said:

Additional authors include Teresa K. Yamana, Sashiki Lankandura, Malta Galanti, and All Mailman Schools. This study was supported by the US National Science Foundation and the Morris-Singer Foundation.

Quoted from a press release by the Mailman School of Public Health.


One in three Americans will be infected with COVID-19 in 2020, the study says

https://news.climate.columbia.edu/2021/08/24/one-in-three-americans-had-contracted-covid-19-by-the-end-of-2020-says-study/ One in three Americans will be infected with COVID-19 in 2020, the study says

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