If You Had COVID, You're Protected for at Least This Long, New Study Says
Recent research has given more insight into the protection from natural infection.
Time and time again, experts have told us that getting vaccinated is the safest and most effective way to protect against the coronavirus. A prior COVID infection will also trigger antibodies, but getting COVID can put you at serious risk, and research about how long you're protected from reinfection has been mixed. Most experts, including the Centers for Disease Control and Prevention (CDC), still recommend that those who have had COVID get vaccinated as well. Now, a new study has given a little more insight into how long you might be protected from the virus if you've already had COVID.
The study, which was published July 19 in the Nature Communications journal, tested nearly an entire Italian town of 3,000 residents in Vo', Italy for infection with COVID between Feb. and March 2020. The researchers from the University of Padova and Imperial College London then tested them again in May and Nov. 2020 for antibodies against the virus.
According to the study, 98.8 percent of the people who had tested positive for COVID in February or March showed detectable levels of antibodies in November—which means that COVID antibodies persist for at least nine months after infection. But study co-author Enrico Lavezzo, PhD, associate professor at the University of Padova in Italy, said that the antibodies were diminished.
"At the follow-up, which was performed roughly nine months after the outbreak, we found that antibodies were less abundant, so we need to continue to monitor antibody persistence for longer time spans," he said in a statement.
The researchers for the Italian study found that persistent antibodies after nine months were present in patients who had both symptomatic and asymptomatic cases. "We found no evidence that antibody levels between symptomatic and asymptomatic infections differ significantly, suggesting that the strength of the immune response does not depend on the symptoms and the severity of the infection," lead author Ilaria Dorigatti, PhD, a lecturer at Imperial College London, said in a statement.
The researchers tracked antibody levels using three different tests. Dorigatti said that her team found varying levels of antibodies depending on the test used, so "caution is needed when comparing estimates of infection levels in a population obtained in different parts of the world with different tests and at different times."
Protection from vaccination is likely still warranted, even if you've been naturally infected with the virus. A recent study published June 28 in Nature found that both the Pfizer and Moderna vaccines could offer years-long protection against COVID—significantly longer than just nine months. The CDC has also warned that reinfection with COVID does happen.
"Even if you have already recovered from COVID-19, it is possible—although rare—that you could be infected with the virus that causes COVID-19 again," the agency explains. "Studies have shown that vaccination provides a strong boost in protection in people who have recovered from COVID-19."