- Around the world people have tested positive for coronavirus after recovering from COVID-19.
- Doctors say people most likely have immunity against COVID-19 for at least several months.
- Immunity against COVID-19 likely won't last your enitre lifetime, according to experts.
Scientists have learned a lot about the novel coronavirus since it was discovered seven months ago. But there are still many unanswered questions, such as whether or not you can get COVID-19 twice.
Some people test positive for COVID-19, recover, and test positive again within a few months, according to data from South Korea. In the United States, numerous people have reported testing positive after recovering. However, this doesn't mean that people were re-infected with COVID-19.
"There’s very little evidence of people being reinfected a second time," says Richard Webby, Ph.D., an infectious disease expert at St. Jude Children's Research Hospital.
What we know about getting sick with COVID-19 twice
Doctors think patients who test positive for coronavirus multiple times had traces of the virus in their systems even after they recovered, says Dr. Webby. Inaccurate test results may also account for the phenomenon, says Michael LeVasseur, Ph.D., M.P.H. at Drexel University.
That's not to say the novel coronavirus can't infect you more than once in a lifetime, says LeVasseur.
After you get sick, your immune system creates antibodies to fight future infection of a particular invader, like the novel coronavirus. In this case, people who contract COVID-19 produce antibodies that attack the virus to ward off future infections, says LeVasseur.
The problem is that the novel coronavirus is too new to study how long immunity lasts. Plus, scientists don't yet know whether people who develop mild cases of COVID-19 produce a strong enough immune response to create these antibodies.
When will we know how long immunity lasts?
However, they can look to other coronaviruses, like SARS-CoV and MERS-CoV (SARS and MERS), for a clue.
"With SARS and MERS, the immune response lasts somewhere between four months and two years," says LeVasseur. If you recover from COVID-19, LeVasseur says you're unlikely to get reinfected within the next four months.
"There’s still so much that we don’t know about this virus and still so much we don’t understand about the immune response to this virus," says LeVasseur.
To determine the length of immunity, scientists need long term studies looking at whether people contract COVID-19 over the course of several years.