A woman wears a face mask outside after the Michael Kors FW20 Runway Show on February 12, 2020 in New York City. Photo by John Angelillo/UPI | License Photo

Feb. 27 (UPI) -- City and state health departments have asked hundreds of Americans to "self-quarantine" to protect against community spread of the novel coronavirus, as fears of the potential pandemic reaching the United States continue to grow.

In New York state, health officials acknowledged that more than 700 residents have been asked to remain in isolation, either because they have traveled to China since the start of the outbreak there, or because they have had close contact with someone who has.


Many already were released from quarantine, which typically lasts for 14 days, provided they remained symptom free and didn't test positive for the virus.

As many as 8,400 people in California also have been asked to take similar measures, while health officials in Ohio have confirmed that 175 state residents have done so.

Many of those on self-quarantine in California arrived on domestic flights, although their travel itineraries may have included China or they may have been exposed to other passengers who traveled there.

In California, the self-quarantine measures have been complicated by the shortage of test kits capable of confirming COVID-19, according to Gov. Gavin Newsom. He said Thursday that the state has 200 test kits, a number he called "inadequate" to assess all the suspected cases.

The governor added that state public health officials have been in "constant contact with federal agencies" and new kits should arrive by early next week. Earlier this week, the U.S. Centers for Disease Control and Prevention confirmed that the test kits it shipped out to states were flawed and needed to be replaced.

So far, 33 people in California have tested positive for the virus, but five have since left the state. On Wednesday, health officials there reported the first known case of the virus in the United States of unknown origin -- meaning the person had no history of travel to an area with a reported outbreak and was not exposed to another known infected person.

On Monday, health officials in Massachusetts indicated that they were monitoring 231 people in self-quarantine.

"When we look at this current COVID-19 situation, we don't speculate on how or when it will spread, so the most important thing I can tell people today is that we at the Department of Public Health are prepared," State Public Health Commissioner Monica Bharel told WBUR radio.

"We are prepared to address what comes our way. People should live their lives normally and go about their normal activities."

Several other states, including Illinois and Wisconsin have asked residents to self-isolate, but are not releasing figures to protect their privacy and limit potential panic.

The self-quarantine measures are in accordance with policy recommendations by the CDC and the State Department. Both agencies have overseen quarantines for Americans evacuated from Wuhan, China -- epicenter for the outbreak -- and the Diamond Prince cruise ship, where an outbreak occurred.

In fact, COVID-19 marks the first time the United States has had to implement quarantines in more than 50 years -- since smallpox in the 1960s.

According to the CDC's guidance, updated Thursday, agency teams are working with the Department of Homeland Security at 11 airports across the country to which all flights from China are being directed so that travelers returning to the United States can be screened.

Passengers with suspected COVID-19 are referred to their local health departments for oversight of self-monitoring.

CDC also has been working with other U.S. government agencies, including the Department of Defense, Health and Human Services and the State Department, to "safely evacuate" U.S. citizens, residents and their families from international locations where there is "substantial, sustained transmission of COVID-19," including roughly 600 from Wuhan and more than 300 from the Diamond Princess cruise ship.

All of these evacuees have been housed on military bases and monitored for symptoms of the virus for the recommended 14-day quarantine period.