Researchers at Harvard University say an on-again, off-again approach to physical distancing may be the best bet for fighting COVID-19.

In a study in The Harvard Gazette, infectious disease experts at the school say barring the development of a vaccine, staggering periods of physical distancing is better than a “one and done” strategy because it does not allow immunity to build in the population. It would also prevent hospitals from being overwhelmed by patients.

The frequency of the staggered periods is not known until it is determined whether COVID-19 is seasonal like the common cold or flu, but experts say it is very likely to return.