An estimated 94% of people in the United States have been infected with the COVID-19 virus at least once, according to a new paper by researchers at the Harvard School of Public Health.
What is the main reason for the unexpected surge? There was a record-breaking case rate for the omicron variant earlier this year and a modest booster rate below what experts expected.
This is far from good news, but there is a silver lining. According to the authors, as of early November, the proportion of people with some degree of protection from new infections and serious illnesses is “significantly higher than in December 2021.”
“Moving forward is probably the best thing we’ve ever done,” said Dr. Peter Chinhong, a professor of medicine at the University of California, San Francisco who specializes in infectious diseases. It doesn’t mean that you don’t or that you are less likely to get infected. Indeed, cases are on the rise again, public health officials warn.
A preprint of the paper, which has not yet been peer-reviewed, appeared this week on the website MedRxiv. Findings are based on statistical analyzes of diagnoses, hospitalizations, and vaccinations reported by the Centers for Disease Control and Prevention, rather than antibody testing of a representative sample of Americans, and are therefore subject to uncertainty.
The team found that 29.1% of Americans were vaccinated and became infected, 55.7% were vaccinated and became reinfected, 2.4% became infected without being vaccinated, and 7% became infected without being vaccinated. I presumed that I was re-infected. Of those who have never been infected, 3.5% have been vaccinated and 2.1% have not.
Researchers at Harvard, Yale, and Stanford University set out to understand how immunity to the virus has changed since December 2021. The calculations studied the “competing effects” of new vaccinations and infectious diseases, and the reduced immunity they confer.
They compared the situation in November 2022 with the situation 11 months ago, and found that the prevalence of COVID fluctuated by time and region, the degree and speed of immunity decline, reinfections, and vaccination rates. conditions, and the effectiveness of their vaccinations.
They estimate that in December 2021, 59.2% of people had the COVID-19 virus.
“Between December 1, 2021 and November 9, 2022, protection against new Omicron infections increased nationally from 22% to 63%, and protection against Omicron infections leading to serious illness increased from 61% to 63%. increased to 89%,” the analysis found.
The authors warn that “despite high levels of protection in the winter of 2022-2023, the risk of reinfection and subsequent severe disease still exists.” And they warn that the introduction of “more contagious or immune-evading (sub)variants, changes in (human) behavior, or ongoing immune decline” could change the calculus. ing.
The study estimated that 116 million people in the country were initially infected and 209 million were reinfected in less than a year.
As the virus mutates, so does our understanding of how herd immunity affects the spread of COVID.
California’s biggest surge each year of the pandemic occurred during the winter holidays, but the fact that so many people contracted COVID earlier this year means fewer people may be vulnerable this holiday season. Earlier this year, the first Omicron wave shattered all previous case records, sickening millions of people, but also Raised the population’s immunity levels, at least for a while.
Even with high levels of immunity, COVID remains a killer virus.
“In the United States, we have an unbelievable number of deaths per day,” Chin-Hong said. “
California’s weekly COVID death toll has remained below 200 each week so far this month, a far cry from the more than 3,779 deaths reported in a week in early January 2021.
While this is a big improvement, “it’s still not something to celebrate,” Chinhong said, noting that the virus remains the leading cause of death in the country.