Official Website (J&J) – Fact Sheet (source FDA) – Twitter handler: @JNJNews

The ‘technical’ name is JNJ-78436735 and it has been developed on viral vector technology. It has been developed by Janssen Pharmaceutica, a Belgian pharmaceutical company founded by Janssen in 1953 and fully owned by J&J.
The vaccine consists in 1 shot in the muscle of the upper arm. It is reported to be effective at 66.3% in clinical trials, while in USA it seems to be around 73% and efficient to prevent hospitalization and death at 100%.
Whoever had previously received an mRNA COVID-19 vaccine dose should wait at least 28 days to receive Janssen COVID-19 vaccine (as from CDCD guidelines)
Storage (as from CDC guidelines)

Price (approx) 10 USD per dose
It is reported to have side effects like pain the injected spot, and sometimes tiredness, headache, muscle pain, chills, fever and nausea.
It is reported to be working against the latest variants, but less against those from South Africa and Brazil.
Countries that have approved and that are using this vaccine against covid19: so far it is approved by USA and EU agencies, as much as from WHO. It is worth mentioning that COVAX has 100 million doses from J&J for 2021 with option of another 100 millions and 300 millions for the next year (here the news from J&J website)