In total 49.7 per cent of Americans, aged 18 years and older, have received at least one dose of the vaccine and 31.8 per cent are fully vaccinated against the novel virus.
It means that across the entire US population, 39 per cent have received at least one dose of vaccine and 24.8 per cent are fully vaccinated.
The milestone comes as it was announced that anyone aged 16 and up will be able to access a vaccine starting on Monday.
Most states have already opened up vaccine eligibility to all adults but President Joe Biden has further pushed every state to open access on 19 April.
However Americans aged 16 and 17 will only be allowed to receive the Pfizer vaccine, the only one which received emergency use authorisation from the Food & Drug Administration (FDA) for that age group.
Pfizer, Moderna, and Johnson & Johnson all received emergency use authorisation for their Covid-19 vaccines.
However the rollout was impacted on Tuesday when the FDA announced a pause in the J&J one-dose shot following six cases of severe blood clots. More than 6.8 million J&J jabs have been administered in total.
The CDC called an emergency meeting of its independent vaccine advisory committee on Wednesday to review the cases and make a determination if use of the J&J vaccine should continue in the US. The panel was unable to reach a decision and will meet again on 23 April after more data has been collected.
Dr Anthony Fauci said this weekend that federal agencies would likely end the pause on the J&J vaccine, and that decision could come as early as Friday.
"My estimate is that we will continue to use it in some form. I doubt very seriously if they just cancel it. I don't think that's going to happen. I do think that there will likely be some sort of warning or restriction or risk assessment," Dr Fauci told NBC's Meet the Press.
Critics have warned the situation with J&J vaccine could further increase hesitancy among unvaccinated Americans.
Although anyone aged 16 and older will be able to access a vaccine from Monday, the US is expected to soon see demand for the vaccine diminish.
Two polls this week revealed that vaccine hesitancy was highest among Republicans. Some 45 per cent of party voters said they have "no plan" to get vaccinated, according to a poll from Quinnipiac University, while 43 per cent of Republicans "likely will never" get a shot, according to a Monmouth College survey.
The Quinnipiac poll found that just 29 per cent of independents and 7 per cent of Democrats said they would not get the vaccine. In the Monmouth University survey, just 22 per cent of independents and 5 per cent of Democrats said they wouldn't get the vaccine.