This is from a NYTimes article but they have a paywall. Can people develop immunity to COVID-19 after catching it?
It’s one of the most pressing questions: Do people who recover from Covid-19 develop immunity to the virus?
So far, evidence points to a qualified yes. If that bears out, it will have big implications.
Survivors could return to work before the outbreak is over and help reboot the economy; immune doctors and nurses could care for the critically ill without fear.
Crucially, the antibodies their bodies produce could speed the search for an effective treatment. But a lot is still unknown. For instance: Do the antibodies give lifelong immunity — as with polio or measles — or is the protection narrow and likely to fade, as with antibodies for colds and the flu? (Even if you can get reinfected, it’s likely the symptoms would be milder the second time.)
Another critical question: Do people who get the coronavirus but do not become very sick produce enough antibodies to protect them, at least until a vaccine can be introduced?
The quickest answers lie in blood tests, which can detect the antibodies. These tests have been used in China, Singapore and some other countries, but are not yet widely available.
Researchers in New York have an antibody test that they say can be scaled up quickly, but it is not yet approved. Here’s another link that was written on 23 March, 2020
https://www.newscientist.com/article/mg24532754-600-can-you-catch-the-coronavirus-twice-we-dont-know-yet/