Studies are under way into how effective a third shot of the Pfizer/BioNTech vaccine could be in increasing the immune response against coronavirus.
Researchers will be examining whether having a second booster dose would offer more protection in cases of COVID-19 caused by existing and also new variants of the virus – like the one first found in South Africa.
Real-world data from Israel’s health ministry recently suggested the risk of becoming ill with coronavirus falls by 95.8% after two Pfizer jabs.
The vaccine was also 98% effective in preventing breathing problems or a fever and 98.9% effective in preventing hospitalizations and death, the ministry added.
Speaking to NBC on Thursday, Pfizer chief executive Albert Bourla said: “We believe that the third dose will raise the antibody response 10 to 20 fold.”
People who took part in the original phase one or two trials and who are trialing a third shot will get their new jab six to 12 months after their initial set of injections.
The third shot will be exactly the same as what participants got before.
The study will include 144 people spread across the age groups of 18-55 and 65-85 in the United States.