The virus has now spread to at least 12 states, with almost 90 cases in all. Both U.S. fatalities were in Washington state — residents of a King County nursing home where dozens more were sick and being tested for the virus. Both of the victims had underlying health conditions.

The disease has killed more than 3,000 people globally and infected almost 89,000, with the vast majority of cases and deaths in China. While the number of new cases recorded daily in that epicenter country has declined…