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

If most transmission occurs before disease is apparent (as happens in HIV), reactive control measures (where public health workers wait for cases to appear in order take measures like contact tracing and quarantine) will be ineffective. Conversely, successful disease control (as happened with SARS-1) is facilitated by low transmission by asymptomat

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

Because the SARS-1 pandemic is well behind us, it is very easy to compute its CFR by simply dividing all observed deaths by all observed cases. Since the disease killed 916 out of 8,472 people that came to medical attention worldwide, that’s a crude CFR of 10.9 percent. But for some populations, such as elderly people in Hong Kong, as many as 50 pe

But the ship still offered observable evidence, and in the confusing early days of the pandemic, scientists pored over the data in dozens of papers, searching for any kind of signal in the noise. This defined and contained population of 3,711 people who were not allowed to disembark allowed epidemiologists to ascertain what fraction of a population

The initial “imported” cases set off local outbreaks via cascades of what epidemiologists term community transmission.

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.

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.

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

Why did the SARS-1 outbreak die out after its extraordinary opening act—featuring rapid global spread, many super-spreader events, and rising alarm—whereas the SARS-2 outbreak did not? It was not just that there was somehow a more efficient public health response in 2003. After all, SARS-1 spread to many countries and it did so in many places, from