How COVID will eventually expire and disappear

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A professor has explained the mathematical concept of why she believes the coronavirus pandemic could abate quickly in a new opinion piece Thursday.

Zoë M. McLaren, associate professor at the University of Maryland in Baltimore County, enrolled The New York Times on the mathematical concept of exponential decay in relation to COVID-19.

The United States is still a long way from achieving herd immunity, but it could improve a lot before then. The worst pandemic may be over sooner than you think, ”McLaren wrote.

However, McLaren – who is studying policies to combat infectious disease epidemics – said that just because there can be steep declines in cases doesn’t mean COVID-19 is nearing its end.

Exponential growth means the number of cases can double in just a few days. Exponential decay is the opposite. Exponential decay means that the number of cases can halve in the same time, ”McLaren wrote.

A graph shows the exponential growth and decay stages of the coronavirus pandemic in the United States

A graph shows the exponential growth and decay stages of the coronavirus pandemic in the United States

Zoë M. McLaren wrote that the mathematical concept of exponential decay shows how the virus may disappear soon

Zoë M. McLaren wrote that the mathematical concept of exponential decay shows how the virus may disappear soon

McLaren explained that “understanding the exponential dynamics makes it easier to know what to expect in the coming phase of the pandemic.”

She wrote that the situation “will improve quickly as vaccination coverage increases.” According to the Centers for Disease Control and Prevention, 243,463,471 doses of COVID-19 vaccines have been given in the United States as of Saturday.

McLaren stressed the importance of vaccines in ‘plunging the numbers’ by writing that ‘any case of COVID-19 that is prevented cuts off chains of transmission, preventing many more cases down the line.’

However, those declines will slow over time and cases are likely to increase again “if people take less action too soon.”

“ For example, if you cut 1000 cases by half every day, it means a reduction of 500 cases on Day 1 and 125 cases on Day 3, but only 31 cases on Day 5, ” she wrote.

McLaren noted that an exponential decline has already been observed in the United States, as it took only 22 days for the number of daily cases to drop by 100,000 from a peak of about 250,000 on January 8 to about 150,000 on January 31.

But it took more than three times as long for daily cases to drop another 100,000, McLaren wrote.

According to the CDC, the current 7-day moving average of daily new cases is 52,528, which means a 79% decrease from Jan. 8.

The concept of exponential growth and decline as applied to the coronavirus pandemic was already explained in a March article in Design News – a publication for the technical community.

No virus can grow exponentially forever. Virus growth is limited by available resources, such as uninfected hosts, transmission medium, nutrients, water, etc. Yet the initial exponential growth of viruses is increasing at an alarming rate, ”the outlet reported.

Fortunately, this kind of contagious growth rate does not go on indefinitely. As the growth rate peaks and begins to decline, the curve changes from an exponential to a normal distribution or clock curve … as the growth pattern begins to decline. ‘

McLaren wrote that “achieving herd immunity is an important goal.”

“It drives cases to zero by slowing the spread of the virus through a combination of vaccination and infection-acquired immunity to sustain an exponential decline – even as society resumes its normal activities,” she wrote.

A map of the United States shows that there have been a total of 32,369,584 coronavirus cases with 576,553 deaths

A map of the United States shows that there have been a total of 32,369,584 coronavirus cases with 576,553 deaths

A graph shows that there have been a total of 32,351,728 cases of coronavirus in the United States since the start of the pandemic

A graph shows that there have been a total of 32,351,728 cases of coronavirus in the United States since the start of the pandemic

A graph shows the daily number of coronavirus infections in the United States in March and April

A graph shows the daily number of coronavirus infections in the United States in March and April

A graph shows that there have been a total of 576,291 deaths from coronavirus in the United States since the start of the pandemic

A graph shows that there have been a total of 576,291 deaths from coronavirus in the United States since the start of the pandemic

A chart shows the daily number of deaths from coronavirus in the United States in March and April

A chart shows the daily number of deaths from coronavirus in the United States in March and April

However, McLaren warned that achieving herd immunity will not prevent all outbreaks – just that they can be easily “extinguished” until the “outbreaks themselves become less and less common.”

In another opinion piece in The New York Times on Saturday, Drs. Carl T. Bergstrom and Natalie Dean noted that “once sufficient immunity is built up in the population, each person will infect less than one other person.”

“But an epidemic already underway will continue to spread,” Bergstrom and Dean wrote. “If 100,000 people are contagious at peak and each infects 0.9 people, that’s still 90,000 new infections, and more after that.”

They added, “A runaway train does not stop when the track starts to slope uphill, and a rapidly spreading virus does not stop immediately when herd immunity is achieved.”

Bergstrom and Dean wrote that if the pandemic in the United States went unchecked, “it could continue for months after herd immunity was achieved, infecting many millions more in the process.”

“By the time the epidemic ended, a very large portion of the population would be infected – well above our expected herd immunity threshold of about two-thirds,” Bergstrom and Dean wrote.

In her article, McLaren said COVID numbers can be rapidly reduced by the concept of exponential decay “even before vaccination coverage reaches herd immunity.”

She explained that the way to do that is by wearing masks and other preventative measures.

She wrote, “ Anything people can do to slow transmission helps – including wearing masks, getting tested, and avoiding overcrowded interior spaces – especially given concerns about current and future variants, as this pushes us over the threshold. could bring an exponential decay. ‘

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