All essential employees in San Francisco now have access to COVID-19 coronavirus testing, as well as any resident who is experiencing symptoms and can't otherwise get tested, Mayor London Breed announced Wednesday.

The expanded testing has begun at the city's two CityTestSF sites and all residents and essential workers, regardless of their insurance status, can make an appointment online.

Also starting this weekend, a coalition will launch a massive testing campaign in the city's Mission district.

A partnership between UCSF, the Latino Task Force for COVID-19 and SF's Department of Public Health is offering free coronavirus testing as part of a study for all persons age 4 and older in part of the Mission. The area includes about 5,700 people living between South Van Ness and Harrison and Cesar Chavez and 23rd streets.

Testing will be held Friday through Tuesday at Garfield Park and Parque Niños Unidos. At-home testing for homebound residents will be on April 29. More community testing locations are pending.

According to Breed, increased testing for the virus is critical to slow its spread.

"Our goal is for every San Francisco resident who has symptoms of COVID-19 to have access to testing. We want to ensure all frontline and essential employees that leave their homes every day to serve our residents have a fast, easy, and accessible option for testing," Breed said in a statement.

"We also want those who don't have insurance, or who lack access to health care or access to basic services to know they can be tested through CityTestSF and receive the support and health care they need," she said.

One CityTestSF site is located at Piers 30-32 and the other is in the South of Market neighborhood. Combined, the two sites are capable of testing as many as 1,500 people experiencing COVID-19 symptoms a day.

The Piers 30-32 site functions as a drive-thru and walk-thru testing facility for health care workers, first responders and all essential workers, including essential workers at private companies and small businesses like grocery store workers, social workers, restaurant employees, transit providers and delivery workers.

The site was previously reserved for first responders and health care workers, but last week expanded to also test all city contractors and non-profit providers, including janitorial staff, street cleaners, homeless service providers and in-home supportive service workers.

The SoMa site, located at 600 Seventh St., is available to all residents who have symptoms regardless of their age, and also offers drive-thru and walk-thru testing as well as language translation services.

The site was previously only tested high-risk populations.

"The expansion of CityTestSF is a leap forward in our fight against the coronavirus," Health Director Dr. Grant Colfax said.

"Since the beginning, our response to the coronavirus emergency has focused on protecting vulnerable populations, health care workers and first responders, and intervening where it can make the most difference. It is critical to test essential workers and other people with symptoms, so that swift action can follow to provide care, contact investigation, and isolation and quarantine to reduce the risk of further exposure and slow the spread of the virus," Colfax said.

The expanded testing is made possible through a partnership with Burlingame-based company Color and San Francisco-based company Carbon Health, the mayor's office said. One Medical is also involved.