Boris Johnson is right to continue to underpromise as he revises the vaccination targets

After a year of over-optimistic bluster, the prime minister is in the happier position of being able to revise his cautious coronavirus targets in a hopeful direction. Boris Johnson announced that the plan to offer a first dose of a vaccine to all adults by “autumn” has been accelerated to the end of July, while the target for offering a first dose to over-50s and younger adults “at risk” has moved from the end of April to 15 April.

There are good grounds for thinking that these targets are still designed to be easily beaten. As the rate of vaccination continues to increase, it should be possible to offer a vaccine to all over-50s by the end of March, and to all adults well before the end of June.

However, the tactic of underpromising and overdelivering is a sensible one. Usually, The Independent would favour the setting of an almost impossible target, in order to exert maximum pressure on the bureaucracy. That was the approach to increasing testing capacity last year. It was the right approach then, even if it led to some dubious double counting. But the vaccination programme is different, in that the constraint is not organising the injections, but the supplies of the vaccines. Those supplies were largely determined some time ago, and here we repeat our praise of Kate Bingham, the former head of the vaccines taskforce, whose ambitious and farsighted work ensured that the UK is better placed in that respect than any other large nation.

The setting of targets for vaccinations is therefore more about managing public expectations than an instrument for trying to drive forward the programme. In which case it is better for national morale to set targets that will be reached early.

That does mean, however, that public opinion is being given less time to adjust to the improving situation. The significance of what is now the 15 April deadline is that it is the point at which a vaccine will have been offered to those groups that have accounted for 99 per cent of coronavirus deaths. Of course, “offered” is not the same as “vaccinated”, and people need to wait three weeks for the vaccine to take effect, but it is likely that by the end of April the overwhelming majority of people who might die of coronavirus will be protected.

That will probably change perceptions of the virus, and more quickly than most people, ground down by 11 months of restrictions, currently expect.

Of course, there are known unknowns and unknown unknowns that could still go wrong, which is why the prime minister is wise to be cautious in setting out a possible timetable for the months ahead. But the recent news has been good. The vaccines seem to offer more protection than thought. A single dose of Pfizer seems to offer almost as much protection, 93 per cent, as a double dose, 95 per cent; and all the vaccines seem to reduce transmission significantly. These developments render debates about the gap between first and second doses, and about vaccine passports (for domestic use), less important.

Instead, it is time to start lifting our sights to what the UK can do to help vaccinate the rest of the world after July. Mr Johnson was right to emphasise this when he spoke at the G7 virtual summit on Friday, and to advertise the UK’s contribution so far to the Covax scheme to deliver vaccinations to the developing world.

On that front, too, he should continue to underpromise, but we trust that the UK government will overdeliver.