The Johnson & Johnson[JNJ] Covid-19 vaccine has been authorized for emergency use by the U.K. medicines regulator, the Medicines and Healthcare products Regulatory Agency (MHRA).The single-dose vaccine, developed by healthcare company J&J’s Janssen unit, has been shown to be 66% effective in preventing moderate-to-severe cases of Covid-19 in its late-stage trial.“As Janssen is a single-dose vaccine, it will play an important role in the months to come as we redouble our efforts to encourage everyone to get their jabs and potentially begin a booster program later this year,” said health secretary Matt Hancock, in a statement on Friday.The U.K. government said it has secured 20 million doses of the Johnson & Johnson vaccine and that it would be made available later this year. The government noted that the vaccine can be stored at refrigerator temperatures, “making it ideal” for distribution to care homes and other locations.The J&J shot is the fourth to be endorsed for use in the U.K., alongside the vaccine developed jointly by U.S. drug company Pfizer and German biotech BioNTech ; the one made by U.K.-Swedish drug company AstraZeneca in collaboration with the University of Oxford; and biotech Moderna’s vaccine.The J&J vaccine was authorized for use in the U.S. in February and in the European Union in March.Source: marketwatch