CHARLOTTE, N.C. — Since the beginning of the pandemic scientists, doctors, and everyone in between has wondered how long robust immunity persists following recovery from a SARS-CoV-2 infection. Now, researchers from Yale University and the University of North Carolina at Charlotte have some deflating news. They report strong COVID-19 protection after recovery does not last very long.
“Reinfection can reasonably happen in three months or less,” explains lead study author Jeffrey Townsend, the Elihu Professor of Biostatistics at the Yale School of Public Health, in a university release. “Therefore, those who have been naturally infected should get vaccinated. Previous infection alone can offer very little long-term protection against subsequent infections.”
Study authors reached these less than ideal conclusions by analyzing reinfection and immunological data collected from close viral relatives of SARS-CoV-2 that cause “common colds.”
They also included immunological datasets from both SARS-CoV-1 and Middle East Respiratory Syndrome (MERS). By leveraging evolutionary principles, researchers believe they were able to accurately model COVID-19 reinfection risk over time.
COVID variants raise the risk of reinfection
While reinfections among those who have already recovered from COVID-19 are already somewhat common, the research team warns such events will likely become even more commonplace as more variants emerge.
“We tend to think about immunity as being immune or not immune. Our study cautions that we instead should be more focused on the risk of reinfection through time,” explains study co-leader Alex Dornburg, assistant professor of bioinformatics and genomics at the University of North Carolina at Charlotte. “As new variants arise, previous immune responses become less effective at combating the virus. Those who were naturally infected early in the pandemic are increasingly likely to become reinfected in the near future.”
According to the research, the reinfection risk associated with COVID-19 is very similar to that of endemic coronaviruses.
“Just like common colds, from one year to the next you may get reinfected with the same virus. The difference is that, during its emergence in this pandemic, COVID-19 has proven to be much more deadly.” Prof. Townsend adds.
“Due to the ability of SARS-CoV-2 to evolve and reinfect, it, too, is likely to transition from pandemic to an endemic disease,” Prof. Dornburg notes.
“A hallmark of the modern world is going to be the evolution of new threats to human health,” Prof. Townsend concludes. “Evolutionary biology — which provided the theoretical foundations for these analyses — is traditionally considered a historical discipline. However, our findings underscore its important role in informing decision-making, and provide a crucial stepping stone toward robust knowledge of our prospects of resistance to SARS-CoV-2 reinfection.”
The findings appear in The Lancet Microbe.