The great news about this vaccine is, it is single-dose. Just imagine what it takes for two doses given a month apart, imagine the savings of all sorts. Also, it can be stored betwen 36 to 46 deg F and again appreciate the savings.
The initial doses of this vaccine going out to the states and other organizations is estimated between 3 and 4 million. J and J is expected to provide some 20 million doses by the end of March.
The J and J vaccine may be better against the B.1.351 strain from South Africa. The two other vacciness are less effective against this strain.
How does J&J vaccine work:
This is a quote from the source below the quote:
"The J&J vaccine is what is known as a non-replicating viral vector vaccine, using a common cold virus called adenovirus 26.
Scientists made this vaccine by taking a small amount of genetic material that codes for a piece of the novel coronavirus and integrating it with a weakened version of adenovirus 26. J&J scientists altered this adenovirus so it can enter cells, but it cannot replicate and make people sick."
[https://www.msn.com/en-us/health/medical/how-the-johnson-johnson-covid-19-vaccine-works-and-why-it-s-important/ar-BB1ddvPZ]
More here on the FDA recommendation:
https://www.msn.com/en-us/health/medical/fda-panel-unanimously-recommends-third-covid-vaccine-as-j-26j-wins-key-vote-in-path-to-emergency-use/ar-BB1e3GJ5?ocid=uxbndlbing
https://www.msn.com/en-us/health/medical/fda-panel-unanimously-recommends-third-covid-vaccine-as-j-26j-wins-key-vote-in-path-to-emergency-use/ar-BB1e3GJ5?ocid=uxbndlbing