Is a stable immunity to the coronavirus infection COVID-19 formed in the body of an ill person? This question is of interest to many today, and scientists have no clear answer to it yet.

Researchers found that in people who have had other coronaviruses (not those that cause COVID-19), the infection often recurs within a year.

Of 86 New York City residents infected with those coronaviruses, 12 tested positive for the same bug again, US News and World Report said.

A big caveat is, the study looked only at the four coronaviruses that are endemic in humans - the kind that cause nothing worse than cold symptoms.

"They're kind of wimpy," said researcher Jeffrey Shaman, a professor of environmental health sciences at Columbia University Mailman School of Public Health. "People rarely have to go to the doctor for these infections."

For the study, Shaman and his colleague Marta Galanti looked at data on 191 healthy adults and children living in New York City. Between fall 2016 and spring 2018, the participants regularly gave nasal swab samples and reported on any respiratory symptoms they were having.

Eighty-six people tested positive for a coronavirus infection at some point. Of those, twelve (or about 14%) tested positive for the same virus within a year.

"The challenge with this new coronavirus is that it behaves differently," said Dr. Bruce Y. Lee, professor of health policy management at City University of New York Graduate School of Public Health.