If you have COVID-19, do you still need to get vaccinated? How long should you wait before vaccination? Hello and welcome to Science in 5. I’m Vismita Gupta-Smith and these are WHO’s conversations in science. We are talking to WHO’s Chief Scientist, Dr. Soumya Swaminathan.

Let’s start with if I have COVID-19, do I still need to get vaccinated?

After getting COVID, people do get an immune response, but this varies from person to person and it depends on whether you had a mild infection or whether you had more severe infection. And we know from many studies now that if you’ve had a very mild or asymptomatic infection, then many people may have very low levels of antibodies that they form. So this is why we still recommend that even if you’ve had COVID infection, that you should go ahead and take the vaccination when it’s available to you, because the vaccine then serves as a boost to the immune system.

Soumya, how long should I wait after a COVID infection to get vaccinated?

Well, you can take the vaccine actually, once you’ve recovered from COVID. So waiting for a few weeks is recommended. You should have no symptoms at all and you should feel perfectly well when you take your vaccination. However, there are differences between countries. Some countries recommend that people wait for three months or six months till after the infection. And this is because you have natural antibodies which will keep you protected for at least that long. And because there are shortages of vaccine supplies in many countries, they are requesting people who’ve had the infection to wait for three or six months. But from a scientific and a biological point of view, you can take the vaccine as soon as you’ve fully recovered from COVID. At this point of time, we are not sure of exactly the level of neutralizing antibodies that offer protection against an infection. And therefore, we do not recommend that individuals go and get antibody testing done in order to confirm whether they have immunity or not. We have to wait again for more data on what the correlate of protection is.

Soumya, what have we learned so far about immunity that is induced after an infection of COVID-19 versus immunity induced by the vaccines?

The type of immunity that’s developed after natural infection varies from person to person, and it’s very difficult to predict. Vaccines have been standardized in terms of the dose of the antigen that’s being administered, and this was based on many clinical trials that have been done. And so when someone receives a vaccine, we can be fairly confident and predict the kind of immune response they will get – of course in the majority of people. So that’s the main difference between natural infection induced immunity and vaccine induced immunity. There are very interesting studies going on now to look at the immune response when somebody has a dose of a vaccine after having had natural infection and also when two different vaccine types are given one after the other,  so the so-called mix and match approach. And scientists believe that perhaps this type of a hybrid approach might actually give us a much stronger immune response than just natural infection alone, or giving a vaccination with the same vaccine alone. But these are interesting ideas and we have to wait for the data to come from the studies. We’re very confident now that all the vaccines that have received emergency use listing from WHO prevent severe disease and hospitalization due to all the existing variants of SARS-CoV-2 virus. However, we still believe that taking the personal precautions like wearing a mask, maintaining distance, maintaining hand hygiene and avoiding crowded and closed places, as well as the other public health and social measures that governments have put in place are necessary because not enough people in the world are vaccinated. And so wherever you live, it is good to take those precautions in addition to being vaccinated because that’s what’s going to drive infection rates in the community down.