As the United States moves closely toward 500,000 COVID-19 deaths, Dr. Anthony Fauci says the world needs a "universal COVID-19 vaccine" that covers all mutations of the virus. The toll hit 200,000 deaths in September and 300,000 in December.
While daily infection rates are coming down dramatically, thousands of Americans still die every day from the virus, and less than 15 per cent of the USA population has been vaccinated against it.
"I don't think we've vaccinated enough people yet to get the herd immunity", he said.
"It's something that is stunning when you look at the numbers, nearly unbelievable, but it's true", he added, as the toll on the Johns Hopkins University tracking website stood at some 498,000. Biden has pledged to see at least 100 million Americans vaccinated during his first 100 days in office.
At the current pace it would take an estimated nine months to cover 75% of Americans with a two-dose vaccine.
Discussing the recent sharp decline in new Covid cases in the U.S., Fauci said it was "the natural peaking and coming down".
But with vaccinations ramping up across the country, Fauci, the nation's top infectious disease expert, agreed with a recent assessment by President Joe Biden that "we're going to have a significant degree of normality beyond the bad burden that all of us have been through.as we get through fall and winter. much, much better than we're doing right now".
Prime Minister Scott Morrison got the Pfizer/BioNTech vaccine at a medical center in Sydney, in what the government said was a bid to boost public confidence in the vaccinations that have been subject to some anti-vaccine protests.
Mr Biden said last week the programme to deliver vaccines into people's arms is as complicated as the already intense challenges of manufacturing them in huge quantities at speed.
The freezing weather and snow storms that hit the United States for over a week have slowed the nation's vaccine efforts, with some six million doses delayed.
A White House spokesman said the president along with first lady Jill Biden, Vice President Kamala Harris and second gentleman Doug Emhoff would hold a moment of silence on Monday and there would be a candle-lighting ceremony at sundown. "I think he was quite fortunate", Fauci told the outlet. "The vaccines we are currently distributing now, the Moderna and Pfizer vaccines, work very well against the United Kingdom variant".
Underscoring the remaining risks, German Health Minister Jens Spahn urged caution Sunday in the face of rising coronavirus infection numbers, just as schools across the country prepare to reopen.