Downing Street has insisted all adults will be offered a coronavirus vaccine by the end of July as planned despite official estimates of supplies being sharply downgraded.
The Cabinet Office has indicated that an average of 2.7 million doses a week will be given in England until the end of July, down from a previous estimate of 3.2 million.
The Prime Minister’s official spokesman refused to be drawn on “details around supplies and deliveries” of vaccine doses but said “we remain on track” to meet the targets set for the programme.
Supplies of vaccines in April have been constrained by the need to test a batch of 1.7 million doses and delays in a shipment of around five million from India.
But the Cabinet Office scenario, provided to experts on the Scientific Pandemic Influenza Group on Modelling (Spi-M) suggests the squeeze on supplies may continue for months.
Papers produced by Spi-M on February 17 were based on an average of 3.2 million doses a week until the end of July and 3.9 million thereafter.
Spi-M said the central scenario provided by the Cabinet Office for its March 31 paper was “considerably slower”, with 2.7 million weekly doses until the end of July and two million from then on.
A slower scenario suggested that just 2.5 million weekly doses might be available.
The Spi-M summary notes that the two scenarios produced by the Cabinet Office “may not reflect the situation most likely to occur”.
The Prime Minister’s official spokesman said: “The Health Secretary set out a couple of weeks ago now the fact that there will be a slight reduction in April but the key thing to remember is that doesn’t mean that we are not on track to hit our pledges.
“We remain on track to vaccinate all those in phase one by April 15, we remain on track to vaccinate or provide the first dose to all adults by the end of July.”
The rollout will be boosted by the introduction of Moderna jabs later in April alongside the Pfizer and AstraZeneca vaccines already being used.
“I’m not going to get into the specifics of how many we will get this month,” the spokesman said, but “we will have three vaccines that we are able to distribute and that will ensure that we can continue to make sure we are giving people their first doses as well as giving more and more people their second doses”.
Some 26.7 million people in England have had a first dose, the equivalent of 60% of the adult population, leaving around 17.5 million adults needing their initial jab to meet the end-of-July target.