Dr. Paul Offit explains why people previously infected with SARS-CoV-2 can benefit from receiving the COVID-19 vaccine.
Should I still get a COVID-19 vaccine if I was previously infected?
Paul Offit, MD: Hi, my name is Paul Offit. I'm talking to you today from the Vaccine Education Center at the Children's Hospital of Philadelphia. Probably the most common question I get asked these days is, if I've been naturally, or if my child has been naturally affected, do they still need a vaccine? In other words, does natural infection protect against diseases associated with this virus?
Well, when the virus first came into this country, when SARS-CoV-2 virus, the virus that causes COVID first came into this country in January of 2020, that's what everybody wanted to know. So we looked, for example, at people who were infected, had moderate symptoms, severe symptoms to see whether or not when they then were re-exposed to the virus, did they still again get moderate to severe disease, because sometimes natural infection doesn't protect. For example, children who have strep throats can get that strep throat infection again and again and again. People who have gonorrhea can get gonorrhea again and again and again, which is to say natural infection doesn't protect. And when that's true, it's very hard to make a vaccine.
What we did see, however, it was very unusual for people who'd been naturally infected to then get moderate to severe disease the second time. That was good. That meant that now all you had to do was mimic the immune response it was induced by natural infection to then protect against disease, so people could have what the advantage of all vaccines, which is to acquire the immune response, the protective effect of natural infection without having to pay the price of natural infection.
So, there have been a number of recent studies showing that natural infection does offer protection against disease, at least moderate to severe disease.
Now, what vaccination does for people who are naturally infected is it boosts that immune response, and to some extent broadens that immune response. So, there is an advantage to getting a vaccine even after you've been naturally infected, especially as more and more variants come to this country, it is of value to have a broader response, so there is an advantage to having this. But I think it's fair to say that the answer to the question can natural infection protect against moderate to severe disease associated with re-exposures is, yes. But vaccinating people who've been naturally infected offers an even greater immunity, so-called hybrid immunity that offers a broader protection.
Related Centers and Programs: Vaccine Education Center
Last Reviewed on Feb 17, 2022