Apollo's Arrow: The Profound and Enduring Impact of Coronavirus on the Way We Live

These changes occur at fairly regular intervals, like a molecular clock—one tiny mutation every two weeks, on average. Since those mutations happen at random places in the code, the genome of a virus in one part of the world will be slightly different than it is in other parts. By studying these cumulative, haphazard mutations collected from many t

In fact, in many cases, it seemed that the one to two days before a person manifested symptoms was when COVID-19 was possibly most contagious.

This image had first been conjured by an MIT professor of meteorology, Edward Lorenz, on December 29, 1972, at the 139th meeting of the American Association for the Advancement of Science. The details were not exactly the same; Lorenz had used the image of a butterfly flapping its wings in Brazil setting off a tornado in Texas.82 But the image was

The latent period is often shorter than the incubation period in SARS-2, but that was generally not the case in SARS-1. The difference between the latent period and the incubation period is sometimes known as the mismatch period; it’s calculated by measuring the incubation period and subtracting the latent period. The difference between these two p

Only seven types of the coronavirus are known to infect humans. Four of them cause the common cold. Two of those four, OC43 and HKU1, originally came from rodents, and the other two, 229E and NL 63, came from bats. The other three types that afflict human beings are SARS-1, SARS-2, and Middle East respiratory syndrome, known as MERS.

This variation in R0 across individuals in a population can be quantified, and this quantity can have subtle but important effects on the course of an epidemic. The higher this variation (or dispersion), the more likely an epidemic will feature both super-spreading events and dead-end transmission chains. That is, an epidemic involving a population

The disease also displays a great range of severity across patients. Perhaps half of those infected are entirely asymptomatic. For the remainder, the range of outcomes stretches from a mild illness (in most cases) to hospitalization (in perhaps 20 percent of cases) to death (in perhaps as many as 1 percent of cases).

The time between when a person is infected and when he or she shows signs or symptoms is called the incubation period. This ranges from two to fourteen days in SARS-2 (hence the recommended fourteen days of isolation) and is typically about six to seven days. For SARS-1, the incubation period was shorter, ranging from two to seven days. But there i

While COVID-19 patients on average take about seven days from exposure to show symptoms, a meaningful percentage of carriers can spread the disease for two to four days before they are symptomatic.