The Connecticut Department of Public Health issued an alert Sunday, saying that it is “strongly recommending” that all Connecticut residents return to wearing masks indoors, regardless of vaccination status.

From the Connecticut DPH:

“Given the rapid increases in cases of COVID-19 in Connecticut over the last 14 days due to the spread of the Delta variant, the Connecticut Department of Public Health is strongly recommending that ALL CONNECTICUT residents over aged two years, whether vaccinated or unvaccinated, return to wearing masks when in indoor public spaces.”

MORE: Connecticut Department of Public Health

The alert was already in place for Fairfield and New Haven counties as of Friday.

According to the health alert, “Vaccination remains the most important defense against illness and hospitalization from COVID-19.  So-called ‘vaccine breakthrough’ cases have occurred in Connecticut, but they remain rare, and the majority of hospitalizations and deaths in Connecticut and around the country are in unvaccinated individuals.”

Gov. Ned Lamont has not issued a statewide mask mandate.