Yahoo! Lifestyle reports that other COVID-19 vaccine candidates besides Pfizer-BioNTech's and Moderna's are under development, including a single-dose option from Johnson & Johnson. The company has about 45,000 people enrolled in ongoing phase 3 clinical trials, and early data suggests the vaccine has significant potential. The company said that the vaccine also was "generally well-tolerated" in study participants. Click Here to read the article.