How Long Does Immunity Last After You Have Had COVID?
Throughout the pandemic, one of the biggest unknowns about the coronavirus has been how long people are immune after they contract and recover from it. Early indications were that it must provide some immunity , as if multiple infections were possible, they would probably be common. But even a year after the health crisis, the exact duration of this protection is unclear.
A recent study from the UK provides some more data suggesting that after a person recovers from COVID-19, their chance of contracting the virus is reduced by at least 83% for at least five months. The study involved 20,000 healthcare professionals, including 6,614 participants who were found to have antibodies. Compared to those who did not get COVID, those who did get infected are 83% less likely to be reinfected. The actual protection may be higher, as the researchers found 44 “possible” re-infections in this group.
The study has not been peer-reviewed, but you can read reviews from several experts here at the UK Science Media Center, as well as in-depth news articles like this from Nature that provide context.
The study results are more or less consistent with previous work, including this study, which showed that healthcare workers with antibodies to spike proteins had better than 90% protection at 6 months.
The CDC states that people who have had COVID in the past three months do not need quarantine if they are exposed again. Sure, it sounds like people are immune for three months, but they go on to elaborate:
The evidence does not indicate definitively no reinfection during this period, only that the risks of potential transmission of SARS-CoV-2 from recovered individuals are likely outweighed by the personal and social benefits of avoiding unnecessary quarantine.
In other words, it may be possible to get infected again within three months, but this does not seem to be likely.
What does it mean if I have had COVID?
We are going through a time of such uncertainty, with so many unanswered questions, and unfortunately, this is another gray area. In the next year or two, we’ll probably get a better understanding of how long the defense lasts. (This also applies to the vaccine: we know that it works for at least two months, but it is not enough for us to know if the immunity weakens after months, years, or lasts a lifetime.)
So, here’s what the experts recommend: First, you may be comforted by the knowledge that you probably have some protection. This is good news. But this is not important news: you still have to do basically the same thing that we all do.
For example, it is still important to wear masks and follow all normal social distancing guidelines. Don’t feel like you can stand by and cough freely on people or anything like that.
You should also get the vaccine when it becomes available to you. The CDC says you shouldn’t get vaccinated while you have COVID, but it’s okay to get vaccinated after you recover. If you were treated with antibodies while you were sick, this could be the reason for the delay in vaccination, but the infection itself is not.