Scientists in Hong Kong have reported the first confirmed case of reinfection with the coronavirus that causes Covid-19, reportedly backed up by genetic sequences of the two episodes of the 33-year-old man’s infections in March and in August 2020. Naturally, people are worried what this could mean for our chances of resolving the pandemic. Here’s why they shouldn’t worry.

Nearly nine months after the first infection with the novel coronavirus, we have very poor evidence for reinfection. However, virologists understand that reinfection with coronaviruses is common, and immunologists are working hard to determine how long the hallmarks of protective immunity will last in recovered patients.

The rare reports of reinfection so far were not accompanied by virus sequencing data so they could not be confirmed, but they are quite expected and there is no cause for alarm.

Inhospitable hosts

Our bodies do not become impervious to viruses when we recover from infection, instead, in many cases, they become inhospitable hosts. Consider that beyond recovery, our bodies often still offer the same cell types – such as cells of the respiratory tract – that viruses latch on to and gain entry for a cosy haven to uncoat and begin producing more viruses. These target cells are not altered in any substantial way to prevent future infections months after the virus has been cleared by the immune response.

If antibodies and memory cells (B and T cells) are left behind from a recent infection, however, the new expansion of the virus is rather short-lived and the infection is subdued before the host suffers too much – or even notices at all.

Image Credit:   Loren Elliott/Reuters

Post by Amanda Scott. Follow her on twitter

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