As the U.S. looks ahead for the next steps in its coronavirus pandemic response, one question looms arguably above all others: Are people who have already recovered from the virus immune to it? The answer is frustratingly complicated, and evidence is severely lacking. However, according to a new analysis by The New York Times, it seems that people may be able to catch COVID-19 more than once.
In an op-ed published by The Times on Monday, epidemiologist Marc Lipstitch rounded up the best evidence on COVID-19 immunity currently available to make some educated guesses. However, he noted that it requires much more studying and research to draw any real scientific conclusions. With that in mind, he pointed to two studies on general coronavirus immunity, as well as studies on immunity to SARS and MERS. The result did not look promising for long-term immunity to COVID-19.
Very little study has been done on SARS and MERS, the building blocks of SARS-CoV-2 which, in turn, leads to COVID-19. However, Lipstitch pointed out two studies on seasonal coronaviruses of the past, and how people acquire immunity to them. Researchers infected groups of less than 20 people with coronaviruses, then tested their responses to those same viruses a year later. A few people showed no symptoms at all, while others showed slightly reduced symptoms.
Meanwhile, there have been such experiments for SARS and MERS, although scientist have gathered measurements of antibodies in people who have survived those infections. The data showed that some level of increased defenses to these infections persists over about two years, but not absolute immunity as far as they could tell.
"These studies form the basis for an educated guess at what might happen with Covid-19 patients," Lipstitch explained. Scientists are hopeful that people who have survived COVID-19 will have a stronger immune response to it if they are exposed again, but that response will vary greatly from person to person. Those defenses "will offer some protection over the medium term — at least a year — and then its effectiveness might decline," Lipstitch wrote.
Lipstitch provided more evidence to support this inference, but emphasized that it has not been scaled up to the worldwide population. He also pointed out that it is frustratingly hard to gather new data on SARS-CoV-2 or COVID-19 in the midst of a pandemic.
For the general public, this means that it is not safe to assume that people who have had COVID-19 already are immune or resistant to it now. This is a factor that could extend protocols like social distancing into 2021 — until scientists are able to develop a vaccine. The other hopeful option is to make antibody testing widely available, allowing those with up-to-date tests to go out without fear. However, even that would be a massive undertaking, and a big change to day-to-day life.
"I can only hope that this article will seem out of date very shortly — as much more is soon discovered about the coronavirus than is known right now," Lipstitch concluded. For the latest information on the coronavirus pandemic, visit the CDC's website.