China's health minister Ma Xiaowei had a few terrible news on the Wuhan coronavirus - human beings can spread it earlier than they have symptoms.

"The transmissibility shows signs of increasing and the 'walking source of infection' [where patients show little sign of disease] has made it difficult to control and present the condition," Minister Ma Xiaowei, 

Dr. William Schaffner, a longtime adviser to the United States Centers for Disease Control and Prevention, said the new virus is a "game-changer."

Schaffner said incorporating a virus is challenging if the patient was spreading the disease for weeks before they even realized they had it.

"The infection is much more contagious than we originally thought," said Schaffner, an infectious disease specialist at Vanderbilt University Medical Center.

The Wuhan coronavirus has killed more than 50 people in China and infected thousands there and expanded as far as Canada, France, and the United States.

Health officials, according to long-time CDC adviser Dr. Paul Offit, should warn passengers on the flights from Wuhan before the outbreak might have traveled with someone who already had the virus.

US to reevaluate strategy

US health officials, according to the Centers for Disease Control (CDC) and Prevention, deem the Wuhan virus has an incubation duration of about two weeks.

Dr. Jennifer Layden, an epidemiologist with the Illinois Department of Health, said the health official's concern for transmission before symptoms develop is low based on what they know about Wuhan's coronavirus (2019-nCoV).

Assuming that Ma is correct, Schaffner said they are going to have to reevaluate their strategy. 

Are Chinese officers right?

Information often changes in a fast-spreading, ever-evolving outbreak like the Wuhan coronavirus.

Ma, the Chinese health minister, didn't explain why he thinks the virus could unfold earlier than someone has the symptoms - leaving some experts skeptical.

Michael Osterholm, director of the Center for Infectious Disease Research and Policy on the University of Minnesota, said he knows of no evidence - in his more than a decade of working with coronaviruses - where anyone has been found to be infectious during their incubation period.

Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS-CoV) are both a consequence of coronaviruses. Both types of viruses - while each killed hundreds of humans worldwide - amounted to a handful of cases and no deaths in the United States.

Offit, on the other hand, said it would not be surprising if the Chinese health minister is right and the Wuhan coronavirus may spread while people are asymptomatic. He explained that chickenpox, measles, mumps, and rubella spread that way.

Despite that, Offit expressed his confidence that the US can control the outbreak earlier than it gets out of hand.

Offit, a pediatric infectious disease expert at the Perelman School of Medicine at the University of Pennsylvania, said the spread of the outbreak doesn't depend on the period of contagiousness. It also is based on how easily the virus spreads. Some illnesses, like measles, spread without difficulty even to humans on the other areas of a room. Other viruses spread easily with much nearer contact.