Public health officials in Los Angeles County have strongly recommended that local residents wear masks indoors in public places due to increased circulation of the highly transmissible Delta Covid-19 variant across the US.

The Los Angeles County Department of Public Health said in a statement on Tuesday that places include such settings as “grocery or retail stores; theatres and family entertainment centres, and workplaces when you don’t know everyone’s vaccination status”, Xinhua news agency reported.

It’s the second day in a row for the Department to urge people to mask up again in all indoor public places, regardless of vaccination status.

Masks are no longer required for fully vaccinated individuals in most public settings in California after the state announced its decision to fully reopen its economy on June 15.

In the week ending June 12, Delta variants accounted for nearly half of all variants sequenced in Los Angeles County, according to the Department.

Health officials pointed out that fully vaccinated people appear to be well protected from infections with Delta variants, but people with only one vaccine dose of Pfizer or Moderna are not as well-protected.

The US Centers for Disease Control and Prevention said that Delta variants are now responsible for about one in every five new infections across the country, up from approximately one in every 10 the week before.

“Fully vaccinated people are well protected against serious illness and disease caused by variants of concern including the Delta variant,” said the county’s Public Health Director Barbara Ferrer in the statement on Tuesday, adding that she encourages everyone eligible and unvaccinated to take another look at all of the mounting information on the vaccines’ safety and effectiveness.

“Ninety-nine per cent of all new cases of Covid-19 and hospitalizations since January have been among unvaccinated individuals and 99.8 per cent of the people who have tragically died have been unvaccinated. Getting vaccinated is the most powerful protection for you and your community,” Ferrer noted.

Los Angeles County, home to over 10 million residents, was once an epicenter the pandemic in California and the country.

But new cases, related deaths, and hospitalizations have plummeted in the county amid vaccine rollout.

The Los Angeles County Department of Public Health reported a total of 1,249,835 confirmed cases, with 24,482 deaths.