Terrific balanced reporting here by @apoorva_nyc

It’s very important to make some points clear - the article discusses these...

As I and other immunologists have been saying for months, #COVID19 reinfection is likely but what it means is not what many people might think...
1/ https://twitter.com/apoorva_nyc/status/1297934551986180097

Immunity to viruses is not binary. It’s not 0% or 100%.

We have immune memory and like regular memory, immune memory must learn.

Just as repetition is beneficial to learning or to building muscle memory, repetition helps build immune memory...

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In the case of reinfections with #COVID19, or rather, the SARS-CoV-2 virus, it’s likely that reexposures will occur. The important thing is what happens upon reexposure...

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Ideally, for most people who become infected, they will build immune memory. But like learning something just once, it may not fully stick.

When you get reexposed, the virus might infect a bit. But your body will recognize it. It will recall that it has already seen it...

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As a result of that recall or secondary response, it will keep the virus from causing significant disease. At the same time, your immune memory is better solidifying it’s recognition of the virus (boosting immune memory) so it can act even more quickly upon the next exposure

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This is actually the premise of booster vaccine shots and why kids grow up and eventually stop getting sick all the time. They have to build memory through repeat exposures. Each repeat is a mild infection and each less bad than the previous and builds immune memory.

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So while repeat infections may sound scary, they are a natural and expected part of building immune memory against many viruses like coronaviruses.

The big question is whether people are likely to transmit upon second or third infections...

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This is something that is not entirely worked out and there won’t be a single answer. Some people will do better at battling the virus on a second exposure and some people will do less well and maybe will need a bit more training before being able to fully contain it.

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So while some transmission could theoretically occur, and I am surmising, it is likely that transmission will be greatly curtailed during second or third reinfections and instead these will serve primarily as immune boosting events rather than forces of onward transmission.

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