Scientists are looking at the possible efficacy of a third dose of coronavirus vaccine in increasing the immune response against the virus.
A number of leading vaccine manufacturers are looking into additional and new jabs, in a bid to provide further immunity in anticipation of more immune-resistant strains of the virus emerging.
People taking part in a trial in the US will receive a third dose of the Pfizer vaccine six to twelve months after receiving their initial jabs.
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."
‘The challenges of tomorrow’
Other manufacturers are also looking to the future and developing updated vaccines.
Chief executive and co-founder of BioNTech, Ugur Sahin, said: "Our proactive clinical development strategy aims to create the foundation today that will enable us to address the challenges of tomorrow.
"We want to be prepared for different scenarios."
Chief scientific officer at Pfzier, Mikael Dolsten, said that receiving a Covid vaccine could become a regular occurrence in the same way that flu jabs are.
He commented: "The rate of mutations in the current virus is higher than expected.
"It's a reasonable probability that we would end up with regular boosts. And for potent vaccines, it may be that you need to do a strain change every few years, but not necessarily every year."
How effective are existing vaccines proving to be?
Data from Israel, where a vaccine rollout has proceeded at the greatest pace, shows that the risk of becoming ill with Covid is reduced by around 95 per cent once someone has received two doses of the Pfizer jab.
Israel’s data also shows that the vaccine is 98 per cent effective at preventing a fever or breathing problems, and prevents people being hospitalised or dying in 98.9 per cent of cases.