Pfizer and BioNTech have submitted preliminary clinical data to US health authorities as part of their effort to seek authorisation for a third dose of their Covid-19 vaccine for all Americans, according to Reuters.

Last week, the United States approved the booster shot of Pfizer-BioNTech and Moderna vaccines for people with weakened immune systems.

Pfizer and BioNTech presented the results of their Phase One trial that evaluated the safety and efficacy of a third shot.

“The data we've seen to date suggest a third dose of our vaccine elicits antibody levels that significantly exceed those seen after the two-dose primary schedule,” Albert Bourla, Pfizer's Chairman and Chief Executive Officer, said in a statement.