COVID-19 vaccine?

 Which is the most effective COVID-19 vaccine?

The most effective COVID-19 Vaccine at this stage is as clear as mud !!

Having said that, I could throw some light on a few major vaccine categories and their frontrunners.

Viral Vector Vaccines: Viral vector vaccines use a modified version (rather weakened version) of a different virus as a vector to deliver instructions, in the form of genetic material (a gene), to a cell to emulate the viral spike protein. The vaccine does not cause infection with either COVID-19 or the virus that is used as the vector.
“I’m giving you the genes, create the virus and destroy it”.