technologyreview | Starting in the fall of 2016 and continuing into 2018, researchers at
Columbia University in Manhattan began collecting nasal swabs from 191
children, teachers, and emergency workers, asking them to record when
they sneezed or had sore throats. The point was to create a map of
common respiratory viruses and their symptoms, and how long people who
recovered stayed immune to each one.
The research included four
coronaviruses, HKU1, NL63, OC42, and C229E, which circulate widely every
year but don’t get much attention because they only cause common colds.
But now that a new coronavirus in the same broad family, SARS-CoV-2,
has the world on lockdown, information about the mild viruses is among
our clues to how the pandemic might unfold.
What the Columbia researchers now describe in a preliminary report
is cause for concern. They found that people frequently got reinfected
with the same coronavirus, even in the same year, and sometimes more
than once. Over a year and a half, a dozen of the volunteers tested
positive two or three times for the same virus, in one case with just
four weeks between positive results.
That’s a stark difference
from the pattern with infections like measles or chicken pox, where
people who recover can expect to be immune for life.
For the
coronaviruses “immunity seems to wane quickly,” says Jeffrey Shaman, who
carried out the research with Marta Galanti, a postdoctoral researcher.
Whether covid-19 will follow the same pattern is unknown, but the
Columbia results suggest one way that much of the public discussion
about the pandemic could be misleading. There is talk of getting “past
the peak” and “immunity passports” for those who’ve recovered. At the
same time, some hope the infection is more widespread than generally
known, and that only a tolerable death total stands between us and high
enough levels of population immunity for the virus to stop spreading.
All that presumes immunity is long-lived, but what if it is fleeting instead?
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