The pace of England’s vaccination programme could be squeezed to 2.7m a week until the end of July, meaning there would be little surplus for first doses until tens of millions of second doses had been administered.
The latest modelling paper, produced for the Sage scientific advisory committee, said that “the central rollout scenario” provided to academics by the Cabinet Office is “considerably slower” than previously used.
That, the document added, amounts to “an average of 2.7m doses per week in England until the end of July (2m thereafter)” which is compared with “3.2m per week in the previous iteration (3.9m thereafter)”.
The projections form part of the model, published on Monday, used by academics from Imperial College London and Warwick University to estimate how coronavirus could spread as restrictions are progressively unlocked by the government.
Ministers have consistently refused to spell out how much of either the Pfizer or AstraZeneca vaccines will be available in future, leaving the officially sanctioned projections cited in modelling papers the best available public predictions.
The requirement for second doses in England rises to between 2.1m and 2.4m a week from the middle of April, in response to the speeding up of the vaccination programme during January. On paper, that leaves only a small surplus for new first doses of a few hundred thousand a week.
The modelling paper, from the Sage SPI-M modelling subcommittee, added: “As the dates of second doses for the over-50-year-olds are now largely fixed, this slower scenario has the effect of reducing the proportion of under-50-year-olds who are protected at the time of steps 3 and 4.”
Step three is the unlocking currently proposed for 17 May, where indoor mixing will be allowed and pubs and restaurants can reopen indoors. Step four is the final stage of unlocking on 21 June, when in theory nightclubs are supposed to be allowed to reopen.
Although the figures cited are for England, the supply of vaccines is spread around the UK on a population-based formula and the impact on the other nations will therefore be the same. England represents 84% of the UK population, meaning the overall supply on this projection would be about 3.2m a week.
Nadhim Zahawi, the vaccines minister, said at the end of March that “April will be second dose month” and the first dose programme is currently paused amid shortfalls in supply from AstraZeneca, including from its partner plant in India. Those aged under 50 and who are in good health are waiting for a jab.
Questions also loom about whether the AstraZeneca vaccine will be made available to young people amid concerns about a very rare blood clotting condition, which could slow the pace of inoculations further.
On Tuesday morning, Zahawi confirmed the Moderna vaccine would arrive in the UK “around the third week in April” – previously said to be 500,000 doses – and he added there would be “more volume in May as well”.
A previous SPI-M modelling paper published in late February contained higher assumptions about the level of supply. It said vaccinations could hit 4m a week in England from 22 March – although a second, more conservative forecast suggested 4m a week could be hit by 25 April. Both those targets appear to have been missed.
Ministers say the government remains on track to hit its stated target of offering a first dose to every adult in the UK – about 53m people – by the end of July. So far, 31.5m people have had a first jab, of whom 5.4m are fully inoculated.