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A new study found
previous infections prevent severe Covid infection. How should this
impact vaccine policy moving forward? Jason, Chicago
When
you get a Covid infection it functions a little in the same way a
vaccine does. It revs up your immune system to protect you from the
virus. The defenses it develops linger in your body. If you encounter
Covid again that so-called natural immunity can lower your risk of
severe disease, a February meta-study in the Lancet showed.
‘The
immunity conferred by past infection should be weighed alongside
protection from vaccination when assessing future disease burden from
Covid-19, providing guidance on when individuals should be vaccinated,”
the authors wrote. That
shouldn’t be interpreted as an endorsement for developing immunity to
Covid through infection, rather than vaccination, according to Katrine Wallace, an epidemiologist at the University of Illinois at Chicago.
“Covid can
cause chronic health problems,” she says. “So no one should
misunderstand this study to think vaccination in the first place is not
important.”
She also points out that the study looks at the
outcomes of reinfection. That means people who died of Covid aren’t
represented in the data, something epidemiologists refer to as
“survivorship bias.”
The best way to avoid severe infection or
chronic infection from Covid is to not get Covid. And the best way to do
that is to get vaccinated. New CDC data show the bivalent booster that
came out last fall — which only 16% of eligible Americans got — makes a huge difference when it comes to avoiding Covid, according to Wallace. If
it’s too late for you to avoid the virus, you should still stay up to
date on your shots. Both natural immunity and vaccine immunity wane over time. “Real-world
vaccine effectiveness data shows that adults who are vaccinated and
receive a bivalent booster are three times less likely to get infected
than someone who is unvaccinated, and almost 10 times less likely to
die,” Wallace says. — Kristen V. Brown |