Four reasons cited by experts to explain the drastic drop in COVID-19 infections in the United States

In recent weeks, data on coronavirus cases in the United States – which has long been a barometer of the severity of the pandemic – have sent encouraging signals: The rate of new recorded infections is collapsing from coast to coast to coast. ‘other. Coastline and the worst wave but is finally disappearing. But scientists are divided on the exact reason for this phenomenon.

Some point to the rapid pace of vaccine administration against the coronavirus, others say it is due to stationary variationThe natural nature of respiratory viruses and others attribute it to social distancing measures.

However, all explanations come with two important caveats: the country is still in a bad situation, as it continues to register more than 90,000 new cases every day, and recent progress could be undone, either by new variants of the rapidly spreading virus, or by relaxing social distancing measures.

The daily average for new infections in the United States hit an all-time high of 248,200 on January 12., on the basis of data collected and analyzed by The Washington Post. Since, the figure fell daily, hitting 91,000 on Sunday, its lowest level since November.

A former director of the Centers for Disease Control and Prevention endorsed the idea that Americans are now seeing the effect of their good behavior, not the increase in vaccines. “I don’t think the vaccine has a huge impact on case rates“, He said Tom peace in an interview on Sunday on the show Zakaria priced GPS of CNN. “That’s what we do well: stay apart, wear masks, don’t travel, don’t mix with others inside“.

However, Frieden noted, the country’s numbers are still higher than during the waves that took place in the spring and summer and “we are by no means out of the woods.” “We had three waves,” Frieden said. “Whether we have a fourth wave or not is up to us, and the stakes couldn’t be higher.“.

The current director of the CDC, Rochelle Walensky, said in a series of televised interviews on Sunday morning that the behavior of the population will be crucial to avert a new spike in infections and that it is too early for states to cancel warrants calling for the use of masks. Walensky also noted the drop in numbers, but said cases were still “more than two and a half times what we saw in the summer.”

“It is encouraging to see these trends decline, but they are doing it from an extraordinarily high place.”He said in the program Meet the press of NBC.

Researchers at the University of Washington’s Institute for Health Measurement and Evaluation (IHME), which publishes a popular model of the coronavirus, are among those who attribute the drop in cases to vaccines and the seasonality of the virus, which scientists say can allow it to spread faster in cold weather.

In the IHME’s latest report, released Friday, the authors write that cases have “declined considerably,” down nearly 50% since early January. “Of the [factores] they reduce transmission, ”the report said. “1) the continuous increase in vaccination, helped by the fraction of adults ready to accept the vaccine, which reaches 71%, and 2) the decrease in seasonality, which will contribute to reducing the transport potential by August ”.

The model predicts 152,000 more deaths from covid-19 by June 1, but predicts that the vaccine rollout will save 114,000 lives.

Over the past week, the country has collectively administered 1.6 million doses of vaccine per day, according to analysis by The Washington Post from state and federal data. It was the best week yet for the campaign, even surpassing President Biden’s lofty goal of administering 1.5 million vaccines per day.

Nearly 40 million people have received at least their first dose of the coronavirus vaccine, a figure that represents about 12% of the American population. Experts said between 70% and 90% of people need to be immunized, either through vaccination or through a previous infection, to end the pandemic. And some leading epidemiologists agree with Frieden, saying there aren’t enough people vaccinated to reduce case rates.

It also emerged a fourth, less optimistic explanation: there are simply more new cases that go undetected. On Twitter, Eleanor Murray, professor of epidemiology at the Boston University School of Public Health, said that increased focus on vaccine distribution and administration could make testing more difficult. “I’m concerned that this is, at least in part, an artifact of resources going from testing to vaccination,” Murray said of the declines.

The Covid Tracking Project, which collects and publishes data on coronavirus tests, has indeed observed a steady decline in testing, from over 2 million a day in mid-January to around 1.6 million a month later. The latest project update attributes this drop to “a combination of reduced demand, as well as lower availability or accessibility of testing.”

“The demand for testing may have declined because fewer people got sick or were exposed to infected people, but also maybe because testing is not encouraged as muchThe authors write.

They noted that an accumulation of evidence over the holidays likely produced an artificial spike in notifications in early January, but that, even adjusted, it’s still “clearly the wrong direction for a country that needs to understand the moves. virus during a downturn, vaccine deployment and release of multiple new variants. “

Most experts agree on one thing: mutated variants of the virus may be the biggest threat to the country’s recovery. One of them spreads quickly and another, known as B.1.351 – commonly referred to as the South African variant, after the country where it was first detected – contains a mutation that may help the virus to partly escape the natural antibodies and the antibodies induced by the vaccine.

In the United States, fewer than 20 infections with the latter strain have been recorded, but the case of a man in critical condition in France highlights the potentially dangerous consequences of the variant. The 58-year-old man had a mild coronavirus infection in September and was re-infected with the B.1.351 strain four months later.

Whatever the cause of the current decline in new infections, experts have urged Americans not to be complacent.

“Masks, distancing, ventilation, avoiding meetings, getting vaccinated when possible. These are the tools we have at our disposal to continue the long journey through the high mountainsCaitlin Rivers, an epidemiologist at Johns Hopkins University, said on Twitter. “Variations can challenge us, but if we keep reducing transmission we can come to a better place.

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