On Monday, the Los Angles County Department of Public Health announced it “strongly recommends everyone, regardless of vaccination status, wear masks indoors in public places as a precautionary measure” in light of the increasingly transmissible Delta variant.

The precautionary recommendation comes just two weeks after the full reopening of California’s economy. Across the country, the Delta variant is responsible for about one in every five new infections. Last week, the rate was approximately one in every 10. However, it appears that fully vaccinated people appear to be well-protected from the Delta variant. In L.A. County, 10 of the 123 people identified with the Delta variant were fully vaccinated. Of the small number of fully vaccinated people who got sick with the Delta variant, the experiences have been mild, and none of the fully vaccinated were hospitalized.

“While COVID-19 vaccine provides very effective protection preventing hospitalizations and deaths against the Delta variant, the strain is proving to be more transmissible and is expected to become more prevalent,” public health director Barbara Ferrer said. “Mask wearing remains an effective tool for reducing transmission, especially indoors where the virus may be easily spread through inhalation of aerosols emitted by an infected person.”

“This is a pandemic of unvaccinated people,” she emphasized.

The DPH noted transmission of the Delta variant seems to happen within households, as 34 of the 64 cases lived in a household with one or more Delta cases. There is no evidence so far that the Delta variant causes more serious illness.

Until the DPH better understands how and to whom the Delta variant is spreading, it emphasizes the need to focus on maximum protection, such as wearing masks indoors at grocery or retail stores, workplaces, theaters and family entertainment centers.

Los Angeles County data shows a steady increase in COVID-19 cases over the last week, jumping from 172 on June 22 to 366 on June 26.