A total of six months have passed since the World Health Organization warned of a mysterious cluster of pneumonia cases coming out of China. We now know it was the coronavirus.

Some countries were able to address the virus and are on the mend - others, including the United States, are still struggling.

"When you have this much disease in the country, this much infection that's spreading. Sadly, and I take no joy in this stuff, I think everyone is vulnerable once again," says Dr. Sanjay Gupta, CNN Chief Medical Correspondent.

A total of 31 states are seeing week-to-week cases rise. The south and west are getting hit especially hard.

"Potentially in Houston we could go from 1,000 cases per day to 4,000 cases a day if the model is right, and eventually no health system would be able to accommodate this," says Dr. Peter Hotez, of Baylor College of Medicine.

At least 16 states have halted or pushed back reopening plans as a result of a surge in infections.

Unlike the European Union of South Korea, the United States has yet to “flatten the curve.”

Some medical experts say Americans haven’t been vigilant enough.

"It was like as if a patient was getting chemotherapy for cancer, abolished the therapy half-way through, and is upset that the cancer hasn't disappeared,” says Dr. Gupta.

Meanwhile, the University of Washington’s updated COVID-19 death projection for Oct. 1 is just over 175,000. That is about 4,000 less than last week’s forecast.

The U.S. government is supporting three clinical trials of coronavirus vaccines over the next few months. However, a CNN poll in May found one-third of Americas are not interested in getting it.