The company said early data showed that antibody levels jump five to 10-fold after a third dose.

Pfizer and BioNTech have announced that they will seek regulatory approval for a third dose of their Covid-19 vaccine. It's an attempt to boost the efficacy of its vaccine as the Delta variant becomes more prevalent across the world. Research from multiple countries shows the Pfizer shot and other widely used vaccines offer strong protection against the highly contagious Delta variant, however fears remain that other variants may cause problems in the future. "While protection against severe disease remained high across the full six months, a decline in efficacy against symptomatic disease over time and the continued emergence of variants are expected," a statement from the two companies said. In comments made public this week, but filmed back in April, Pfizer CEO Albert Bourla said people will “likely” need a booster dose of a Covid-19 vaccine within 12 months of getting fully vaccinated. This is because antibodies naturally wane over time, so studies also are under way to establish if and when boosters may be needed. Pfizer said that early data from the company’s booster study suggests people’s antibody levels jump five to 10-fold after a third dose, compared to their second dose months earlier. "The companies expect to publish more definitive data soon as well as in a peer-reviewed journal and plan to submit the data to the FDA (Food and Drug Administration), the EMA (European Medicines Agency) and other regulatory authorities in the coming weeks," the statement said. Pfizer said earlier this month that its Covid-19 vaccine was more than 91% effective at protecting against the Covid-19 and more than 95% effective against severe disease up to six months after the second dose.