Yesterday the World Health Organization (WHO) warned that the whole world must be on alert for the coronavirus. It said an expert committee would meet Thursday to determine if the Wuhan coronavirus outbreak should be declared a public health emergency of international concern. That committee has decided today to the virus a world health emergency.

Citing the concern over human to human transmissions found in several countries, a world health emergency has been declared. In just one short week, the WHO has gone from holding back on making such an alert to deciding it is a necessary action. As Jazz has noted, the screening for this virus has been slow to come and of the real possibility of quarantines here in the United States. The Chinese government quarantined millions of its citizens. President Trump said he is working with the Chinese government to do what can be done to stop the spread of the disease.

Human to human transmission has been confirmed in the United States now – a Chicago man’s illness was confirmed Thursday which brings the number of cases confirmed to six in the United States. The declaration by the WHO gives guidance to world governments to make decisions about protecting its residents.

The W.H.O.’s declaration — officially called a “public health emergency of international concern” — does not have the force of law. But it serves notice to all United Nations member states that the world’s top health advisory body thinks the situation is grave.

Governments then make their own decisions about whether to close their borders, cancel flights, screen people arriving at airports or take other protective measures.

There is a money issue, too. So far, the countries affected are those capable of handling the financial burdens of the outbreak. Those countries are China, Japan, Germany, South Korea, the United States, Australia, and Vietnam. Some borders are being closed to prevent spreading the disease and Tedros Adhanom Ghebreyesus, the W.H.O.’s director-general is pleased with China’s aggressive actions to date.

Dr. Tedros, who met with President Xi Jinping in Beijing on Tuesday, said Mr. Xi had led “a monumental national response,” and that he was “struck by the determination of Chinese leadership” and by how much Mr. Xi personally understood about the outbreak.

China said on Thursday that another 38 people had died from the disease, bringing the total to 170. Nearly 8,000 cases have been reported worldwide, almost all of them in mainland China.

On Thursday, Russia closed its 2,600-mile border with China and stopped all trains except for one between Moscow and Beijing.

The Chicago man is married to a woman who was hospitalized after returning from Wuhan, China, the location where the virus originated. Her husband, the new case, didn’t travel with her but apparently caught it from her upon her return. Both are in their 60s. He is now hospitalized, too. Don’t worry, says the Chicago Department of Public Health and others in the field.

“This news may raise people’s concerns, but I want to state clearly that this development is something that we have been prepared for,” Allison Arwady, chief medical officer at Chicago Department of Public Health, said at a press conference Thursday. “It’s not totally unexpected that he acquired the virus.”

“I’m not surprised by a sporadic second-generation case,” said Greg Poland, director of the Mayo Clinic Vaccine Research Group. “But everybody’s holding their breath to see if we’ll have third or fourth generation cases. Did this spouse spread the virus?”

In fact, at a press briefing last week, the CDC’s Dr. Nancy Messonnier warned that “We are likely going to see some cases among close contacts of travelers and human-to-human transmission.”

Ngozi Ezike, director of the Illinois Department of Public Health, said 21 people are being investigated for coronavirus. Health officials said that it is still not yet clear how easily the virus spreads from one person to another.

It does alarm people, though, and for those of us who hold government officials with a bit of natural suspicion aren’t necessarily persuaded by claims of preparedness. There is no vaccine but scientists in Melbourne, Australia have made great strides in that area. They have successfully grown the coronavirus from a patient. In the meantime, we can remain vigilant and take normal precautions. It’s cold and flu season anyway so everyone should be taking care to do the basics of frequent hand-washing and remembering to cover mouths when coughing and turning away to sneeze into your sleeve. Most importantly, get to a doctor if necessary. Don’t panic but stay alert.