More than 156 million US adults have now received at least one dose of the Covid-19 vaccine, a senior health official said on Monday, as the highly contagious Delta variant fuels a nationwide spike in cases.
The milestone, announced by White House Covid-19 data director Cyrus Shahpar, comes almost a month after a deadline set by President Joe Biden passed.
He initially sought to hit the 70 per cent partial vaccination level by July 4, but inoculation rates plunged amid widespread hesitancy about using the new vaccines.
Critics say Mr Biden prematurely declared “independence from this virus".
"While we desperately want to be done with this pandemic, Covid-19 clearly is not done for us," Director of the US Centres for Disease Control and Prevention (CDC) Rochelle Walensky said during a White House Covid-19 Task Force briefing.
An increase in vaccination numbers may be due to concerns with the surge in Delta variant infections. The strain is infecting not only unvaccinated people -- increasing numbers of "breakthrough" cases are hitting those who are fully vaccinated as well.
Lindsey Graham, a senior Republican senator, said on Twitter that he would quarantine for 10 days after testing positive for the coronavirus even though he is vaccinated.
"Each and every shot matters," White House Covid-19 Response Co-ordinator Jeffrey Zients said on Monday, remarking that there are around 90 million eligible people in the US who remain unvaccinated.
Anyone 12 and older can receive the shot, with three different vaccines available.
A growing number of private companies — including Google and Netflix, healthcare centres and others — are requiring employees to be vaccinated against Covid-19. Mr Biden on Friday said federal staffers and contractors would need to be vaccinated or consent to regular testing and other measures.
Last week, the US recorded more than 100,000 positive cases in one day, the CDC reported, the first time that has happened since February.
Dr Walensky also said national daily Covid-19 deaths have grown to 300 per day, a 25 per cent rise in the last seven-day average period.
Florida recorded more than 21,000 cases in one day at the weekend and registered the highest level of hospital admissions since the pandemic started, with more than 10,200 people admitted to healthcare centres with Covid-19.
Florida's cases and hospital admissions follow Governor Ron DeSantis's ban on mask mandates and other Covid-19 mitigation measures in the state after the CDC recommended that vaccinated people wear masks in public indoor spaces.
The southern state of Louisiana is the current coronavirus hot spot in the country, with a seven-day average of 511 infections per 100,000 people. Only 37 per cent of the state's population is vaccinated.
"The seven states with the lowest vaccination rates represent just about 8 per cent of the US population, but account for more than 17 per cent of cases," Mr Zients said.
Mr Biden is expected to give remarks on vaccinations in the US and abroad on Tuesday.
More than 613,000 people in the US have died from Covid-19, Johns Hopkins University data show.