A booster dose of Johnson & Johnson's single-dose COVID-19 vaccine was 84% effective at preventing hospitalization in South African healthcare workers who became infected as the Omicron variant spread, researchers said on Thursday. #Johnson&Johnson #J&JBoosterDose #COVID #Omicron #Coronavirus #Vaccine #News #Reuters Subscribe: http://smarturl.it/reuterssubscribe Reuters brings you the latest business, finance and breaking news video from around the globe. Our reputation for accuracy and impartiality is unparalleled. Get the latest news on: http://reuters.com/ Follow Reuters on Facebook: https://www.facebook.com/Reuters Follow Reuters on Twitter: https://twitter.com/Reuters Follow Reuters on Instagram: https://www.instagram.com/reuters/?hl=en