Despite the two new cases of Middle East Respiratory Syndrome (MERS) reported in the United States and more than 300 cases reported in Saudi Arabia since the virus first appeared there in 2012, the World Health Organization said on Wednesday that the virus is not a global public health emergency.

“Based on current information, the Committee indicated that the seriousness of the situation had increased in terms of public health impact, but that there is no evidence of sustained human-to-human transmission,” the WHO said in a statement about the recent decision. “As a result of their deliberations, the Committee concluded that the conditions for a Public Health Emergency of International Concern (PHEIC) have not yet been met.”

The decision was made after a meeting of the WHO's expert group on MERS. The virus, which presents itself with flu-like symptoms, can lead to pneumonia, breathing problems and in severe cases, kidney failure and death.

More than 500 people have been diagnosed with MERS since 2012. About 30 percent of those have died. Most of the cases have been reported in Saudi Arabia, but the virus has been reported in Asia, North Africa, Europe and more recently, in the United States.

"Calling a global emergency in a world which has a lot of issues is a major act," Dr. Keiji Fukuda, an assistant director-general of the WHO, told reporters on Wednesday. "You have to have really solid evidence to say this is a global emergency."

The second U.S. patient diagnosed with the virus was in Florida, where he spent at least four hours in a public waiting room of a busy hospital, when he was diagnosed with MERS. It was only eight hours into his visit when Orlando's Dr. P. Phillips Hospital determined the patient had MERS, which he contracted on a recent trip he took to Saudi Arabia, where he works in a hospital. The 44-year-old man is expected to make a full recovery.

Hospital patients and staff who might have been in contact with the patient have been tested for MERS. Florida officials said on Tuesday two health care workers have developed flu-like symptoms. Test results are expected on Wednesday.

The first U.S. patient with MERS was diagnosed at Community Hospital in Munster, Ind. All those who had direct contact with the patient were tested for MERS and showed no signs of the infection.

Some scientists have disputed the WHO’s findings, saying that MERS meets the criteria for declaring a global health emergency.  

"People might think [the WHO] is crying wolf because MERS is still primarily a problem in the Middle East," Michael Osterholm, an infectious diseases expert at the University of Minnesota who has worked in the Middle East, told the Associated Press. "But if one of those infected people gets on a plane and lands in London, Toronto, New York or Hong Kong and transmits to another 30 people, everyone will have a different view."

Tom Frieden, director of the Centers for Disease Control and Prevention, said MERS is spread through close personal contact. He says the general public is not believed to be at risk from the virus, he said, but the warnings are being issued "in an abundance of caution."

The WHO said the expert committee would reconvene in several weeks to consider any new MERS developments.