WASHINGTON, June 8 (AFP) - For months, US President Joe Biden has laid out goal after goal for taming the coronavirus pandemic and then exceeded his own benchmarks.

Now, though, the US is unlikely to meet his target to have 70 per cent of Americans at least partially vaccinated by Jul 4.

The White House has launched a month-long blitz to combat vaccine hesitancy and a lack of urgency to get shots, particularly in the South and Midwest, but it is increasingly resigned to missing the president’s vaccination target.

The administration insists that even if the goal isn't reached, it will have little effect on the overall US recovery, which is already ahead of where Biden said it would be months ago.

About 15.5 million unvaccinated adults need to receive at least one dose in the next four weeks for Biden to meet his goal.

But the pace of new vaccinations in the US has dropped below 400,000 people per day — down from a high of nearly 2 million per day two months ago.

Dr Anthony Fauci, the nation’s top infectious disease expert, told reporters at a briefing on Tuesday that he still hopes the goal will be met “and if we don’t, we’re going to continue to keep pushing".

So far 14 states have reached 70 per cent coverage among adults, with about a dozen more on pace to reach the milestone by Jul 4. But the state-to-state variation is stark.

Fauci said the administration is “pleading" with states, particularly those with low vaccination rates, to step up their efforts in the coming months, though some of the states trailing behind are hardly sharing the urgency.

On a conference call on Tuesday, White House COVID-19 coordinator Jeff Zients delivered an impassioned call for governors to join the administration in “pulling out all the stops” on vaccinations this month.

“We need your leadership on the ground – which is where it matters the most – more than ever,” he said.

In Mississippi, which trails the nation with only about 34 per cent of its population vaccinated, Republican governor Tate Reeves has called Biden’s goal “arbitrary, to say the least".

The vaccination rate in the state has dropped off so sharply that it would take the better part of a year for the state to reach the 70 per cent target.

Fauci on Tuesday emphasised that increased vaccination was essential to stamping out potentially dangerous variants, including the so-called Delta variant first identified in India that is now the dominant strain in the United Kingdom and is growing in the US.

Vaccines have proven less effective against that variant when people are not fully immunised, and evidence points to it being more transmissible and more deadly.

In an attempt to drive up the vaccination rate, the White House has worked to encourage an array of incentives for people to get shots — from paid time off to the chance to win a million dollars.