LOS ANGELES (CBSLA) — Health officials in Los Angeles are joining a growing number of jurisdictions urging people to wear cloth masks whenever they go out in public — even as they simultaneously warn the public not to buy surgical masks needed more urgently by health care professionals.

Barbara Ferrer, head of the county Department of Public Health, issued the new guideline while reporting 11 new deaths Wednesday due to COVID-19, nine of whom were over the age of 65 and nine of whom also had underlying health conditions.

As of Wednesday afternoon, Los Angeles County had a total of 3,518 total COVID-19 cases with 513 new cases. Five of those cases involved homeless people, she added.

According to Ferrer, health officials are investigating coronavirus cases at nursing homes, skilled nursing

centers, assisted living facilities, residential treatment programs, shelters, jails, and other “institutional settings.”

She said there have been a total of 207 positive cases at those 43 facilities, and seven people have died.

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When it comes to masks as a form of coronavirus prevention, Ferrer echoed new guidance that people with the virus can potentially spread it 48 hours before they show any symptoms, and said “there may be a benefit” for people to wear a mask when going out in public.

However, Ferrer stressed that residents should not be buying surgical or high-tech N95 masks typically used by front-line health-care providers, but can instead use household items such as scarves, bandannas or fabric.

“Please don’t go out and try to get N95s. We need to protect that supply for our health care providers,'” Ferrer said.

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To be clear, Ferrer said the masks could help those who are unknowingly carrying the virus from spreading it to others.

“But wearing a mask is not a shield, and it doesn’t replace our request that you stay at home, that you always are practicing social distancing, that you’re using handwashing as your major means to make sure you’re not infecting yourself after touching something or someone who may be infected, and that you’re self-isolating and self-quarantined when it’s appropriate,” she said.

In neighboring Ventura County, officials reported an additional 11 cases, bringing the county’s total to 160 cases.