With a state of emergency in Puerto Rico, where mosquito-spread dengue fever is endemic, and two cases of travel-related dengue fever reported in Hawaii last month, a push is growing for U.S. availability of a preventative vaccine, The New York Times reports — but Merck & Co., the developer, has yet to hold clinical trials.

Hawaii has reported 10 dengue infections since Jan. 1, 2023, prompting the state Health Department to urge extra precautions. All cases so far are thought to have been contracted outside of the U.S., but Hawaii’s mosquitoes can carry dengue, which causes fever, body aches and even death. The best protection is to avoid being bitten. Use protective clothing and mosquito repellent; eliminate standing water where mosquitoes can breed.