Speaking at a news briefing, Barroso said it was critical to continue to keep up the pace of vaccine supply through the COVAX global vaccine-sharing programme, as more than 3 billion people in the world have yet to receive their first dose.
Gavi Chief Executive Seth Berkley said there was a need to raise the additional funds in the next three months to establish a pandemic pool of a minimum 600 million additional doses, strengthen countries' delivery systems, and finance ancillary costs for syringes and transport.
"If we achieve this goal, we believe that up to one and a quarter million deaths can be prevented in the next year alone... economic cost of the pandemic could be reduced."
Last week, COVAX reached a milestone of delivering 1 billion COVID-19 vaccine doses.
Speaking at the same event, World Health Organisation Director General Tedros Adhanom Ghebreyesus said scaling up the delivery capacity of COVAX is critical to meeting the UN agency's target of vaccinating 70 percent of the population in poorer nations by mid-2022.