Two more cases of the new strain of coronavirus have been confirmed at the San Antonio military base where some evacuees from a cruise ship were quarantined Monday, the Centers of Disease Control and Prevention said at a press conference Friday. This brings the number of confirmed Texas cases of the strain named COVID-19 to three.

The two evacuees were among 329 Americans repatriated against the CDC's recommendation after disembarking from the Diamond Princess off of Japan. Another 16 cruise ship evacuees quarantined in California and Nebraska have also been confirmed to have coronavirus.

"[The passengers] are considered at high risk for infection, and we do expect to see additional confirmed cases of COVID-19 among the passengers," said Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases, during the press conference.

There are also several Americans hospitalized in Japan who are "seriously ill," she said.

The first Texas case was confirmed Feb. 13 when one of 91 Americans evacuated from the Hubei province of China, the epicenter of the outbreak, was hospitalized. The remaining 90 Americans were released from the San Antonio base Thursday because they showed no symptoms after a 14-day quarantine.

The World Health Organization declared COVID-19 a public health emergency by last month. According to the latest CDC report, there are over 75,000 confirmed cases worldwide, and the death toll has surpassed 2,000. But outside of China, there have been only three fatalities, and none in the U.S.

The total number of confirmed U.S. cases is 34. However, the CDC makes a distinction between cases among repatriated Americans and all other U.S. cases, as the former aren't an accurate representation of how the virus is spreading within the country, according to Messonnier.

"We don't yet have a vaccine for this novel virus, nor do we have a medicine to treat it specifically," Messonnier said.

The goal now is to slow the introduction of the virus into the U.S. to buy time to prepare the community for more cases and possibly sustained spread, she added.

Two elderly Japanese passengers aboard the Diamond Princess died after testing positive for the virus, Japan's health minister said Thursday.

Researchers at the University of Texas at Austin are working on a vaccine, and a Houston-based genetic engineering company announced this week it finished developing one. However, the Food and Drug Administration has not yet approved a vaccine.

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