Over the weekend, U.S. FDA issued an emergency use authorization (EUA) for the third vaccine for the prevention of COVID-19, allowing Johnson & Johnson's Janssen vaccine to be distributed in the U.S for use in individuals 18 years of age and older.

Unlike the Pfizer and Moderna vaccines, the Janssen COVID-19 vaccine is manufactured using an adenovirus type 26 (Ad26) to deliver a piece of the  genetic material used to make the distinctive “spike” protein of the SARS-CoV-2 virus. The vaccine leverages the company’s AdVac viral vector technology, which was also used to develop and manufacture Janssen’s European Commission-approved Ebola vaccine regimen and construct its Zika, RSV, and HIV investigational vaccine candidates.

Importantly, it's a single dose, and it doesn't require special storage. 

The available safety data to support the EUA include an analysis of 43,783 participants enrolled in an ongoing randomized, placebo-controlled study being conducted in South Africa, certain countries in South America, Mexico, and the U.S. Overall, the vaccine was approximately 67% effective in preventing moderate to severe/critical COVID-19 occurring at least 14 days after vaccination and 66% effective in preventing moderate to severe/critical COVID-19 occurring at least 28 days after vaccination.

J&J said last week that it was prepared to ship up to 4 million doses of the vaccine as soon as the EUA was given, 20 million by the end of March, and a total of 100 million doses by June.

Read the Janssen press release