Los Angeles, Sep 20 : Nearly 24,000 monkeypox cases had been confirmed in the US as of Monday, according to the latest data of the US Centers for Disease Control and Prevention (CDC). California had the most confirmed cases among US states so far, with 4,656 cases, followed by New York with 3,755 and Florida with 2,398, Xinhua news agency reported, citing the CDC data. Monkeypox infections are rarely fatal, with most cases resolving within two to four weeks. According to the World Health Organization, the disease has a fatality rate of around 3 per cent to 6 per cent. However, immunocompromised individuals are more likely to experience severe illness when infected, according to the CDC. US health officials are warning doctors against overusing the lone drug available to treat monkeypox. Viruses are constantly evolving to better infect humans and overcome new drugs and vaccines, according to the CDC. The US Food and Drug Administration has warned that the antiviral drug, called Tecovirimat, is highly vulnerable to resistance. Even a small mutation in the virus could leave the drug ineffective. /IANS