Pfizer Inc and its German partner BioNTech SE said on Wednesday they started a mid-stage study of a modified COVID-19 vaccine which targets both the original as well as the BA.2 omicron subvariant.
Pfizer said the vaccine is in an initial proof-of-concept study to gather more data, reports Reuters.
Together, the BA.4 and BA.5 subvariants are estimated to make up nearly 95 per cent of the circulating coronavirus variants in the United States for the week ended Jul 23.