________ vaccine is 90 percent effective six months after the second dose ?

a) Pfizer
b) Moderna
c) Covaxin
d) Covishield

Moderna announced on April 13, 2021 informed that its vaccine is 90 percent effective six months after the second dose is administered. The company in a statement said that new results from a preclinical study of the Company’s COVID-19 variant-specific vaccine candidates showed that its variant-specific booster vaccine candidates (mRNA-1273.351 and mRNA-1273.211) increase neutralizing titers against SARS-CoV-2 variants of concern.