The synthetic drug flakka, which caused numerous hospitalizations in South Florida in 2014 and 2015, appears to have disappeared, CNN reports.

Three or four people were hospitalized every day for flakka use in South Florida last spring, the article notes. It was sold for $5, and was reported to be similar to cocaine but much cheaper and more potent. Flakka comes in white crystals and can be ingested, snorted or injected.

While 63 people died in South Florida due to flakka use between September 2014 and December 2015, there have been no flakka-related deaths in the region so far this year, the article notes.

Treatment centers in Broward County, Florida admitted about 50 people a month for flakka use in the fall, but have admitted only six people who used flakka in January.

“Anecdotal reports from both street users and law enforcement officers say that flakka is not even available in the street drug market,” said Jim Hall, a drug abuse epidemiologist at Nova Southeastern University in Fort Lauderdale. “I have never seen an epidemic emerge so rapidly but literally disappear so quickly.”

Flakka use has also dropped in areas around the country including cities such as Chicago and Houston, as well as rural areas of Kentucky and Illinois, Hall said.

He noted the main factor in the reduction of flakka use was a Chinese ban on the production and exportation of the chemical alpha-PVP, the chemical name for flakka. The Chinese government also banned 115 other street drugs, he noted. The U.S. government, along with European nations, pressured China to ban the substances.

Hall said that in 2014, when China banned the synthetic drug methylone, it was replaced by a similar substance called ethylone. When Ethylone was banned last year, it was replaced by another similar drug, dibutylone.