The "acute phase" of the Covid-19 pandemic could be over by the end of 2021, according to a former White House medical adviser. Dr Richard Hatchett, chief executive of the Coalition for Epidemic Preparedness Innovations, said it was possible to end the worst of the global outbreak through mass vaccination initiatives. But it will be “one of the most complicated logistical operations” ever undertaken, he said. His organisation, founded at Davos and based in Oslo, hopes that between four and six billion people will be vaccinated over the next nine months. “If we can end the acute phase of the pandemic by protecting the most vulnerable, the virus will continue to circulate until we vaccinate almost everyone,” said Dr Hatchett, who served in the Obama and Bush administrations as director of medical preparedness on the national security staff. “But we can take the economic sting and cost of human lives out of the pandemic. And we hope to be able to do that by the end of this year. “We cannot underestimate the challenge of what we are undertaking.” He was speaking at an online conference organised by the Hope Consortium, an Abu Dhabi-based logistics group set up to deliver vaccines around the globe. The conference also heard from Dr Tedros Adhanom Ghebreyesus, director general of the World Health Organisation, who warned the gap between the number of vaccines administered in rich countries and by Covax is growing "every single day". He said the inequitable distribution of vaccines was not simply a moral issue. "It is also economically and epidemiologically self-defeating," he said. "The world will not be safe until everyone is safe, as the more transmission there is, the more variants there will be. "And the more variants that emerge, the more likely it is that they will evade vaccines. As long as the virus continues to circulate anywhere, people will continue to die.” The scale of the operation needed to address the issue is "truly unprecedented", he said.