In recent months, there has been huge enthusiasm over the possibility of a Covid-19 vaccine. I know because I have experienced it myself, dreaming of the day I roll my sleeve up in the GP surgery; small pain, big gain, I might whisper to myself. Everyone wants a way out of this nightmare, and with every Government announcement of investment for vaccine studies, it was easy to get carried away – that this was the way out.

Over the weekend, the prospect of a vaccine became all the more palpable when The Mail on Sunday released photographs from inside US pharmaceutical company Pfizer’s Belgian factory, in which thousands of doses were whisked through the production line. That same day, The Sunday Times reported that Jonathan Van-Tam, one of the Government’s chief scientific advisors, has said that one version, manufactured by AstraZeneca, could be ready as early as December.

But why all the excitement? For shortly afterwards Patrick Vallance, the Government’s Chief Scientific Adviser, delivered a crushing blow to the vaccine dream, telling those on the joint committee on National Security Strategy that the “notion of eliminating Covid is not right”. He added that the disease would “start to look like annual flu more than anything else and that may be the direction we end up going.”

Vallance’s words should remind us that while the Government initially placed a lot of political hope in a vaccine, ministers are actually moving in a different direction now – to a new testing programme entirely. As Paul Goodman wrote for ConservativeHome on Monday, this would involve rapid “lateral-flow” tests, which render a tracing programme obsolete, as well as the Government using LAMP tests – concentrated on testing asymptomatic NHS staff.

This is a sensible direction – for all the excitement around vaccines, the truth is that they’re just as likely to have major hiccups as test and trace. That much is obvious from both medical and political perspectives.

On the first front, what’s obvious is that it’s incredibly hard to completely vaccinate against a virus. Indeed, smallpox is the only disease that has ever been completely eradicated by a vaccine. Kate Bingham, the chairman of the UK Vaccine Taskforce, has said that a Coronavirus vaccine would probably have the same success rate as the flu jab (50 per cent). But even that could be optimistic. SARS and MERS come from the same Coronavirus family, and do not have vaccines (though there are candidates being developed for MERS).

Optimists will point out that the World Health Organisation is currently tracking 196 studies into Covid-19, which is a fantastic number. Even so, an expert in medical innovation tells me it’s quite hard to make predictions about which will be a success – because of the ways vaccines are created. They tell me that “the vast majority of majority of new drugs and vaccines that are developed fail. It’s not like a construction project, where you know it’s possible to build the building, but you can run into unforeseen issues.”

“It’s more like you don’t know if you’re taking the right approach to constructing the building in the first place, and it may never get built. There are multiple approaches to vaccine development and it’s not clear yet which may or may not succeed.”

If we do get a vaccine, the next big hurdle is making sure it passes rigorous safety assessments that could add a lot more time onto the process. It can be expected that some governments will try to bypass important regulatory processes (the Chinese government has allowed citizens to get a vaccine that hasn’t completed clinical trials, with people queueing up for it).

And then there’s the next question of who gets the vaccine. This is already causing a political headache, especially when (aforementioned) Bingham said that only 30 million of the 67 million people who live in Britain woud get a vaccine. Already MPs are getting ready for warfare; in the House of Commons yesterday, James Grundy, the Conservative MP for Leigh, asked the Government to prioritise areas which have lived with restrictions longest when and if the vaccine comes.

This is far too premature a question, incidentally; there is no vaccine, and when it arrives there’ll be a global response to who gets it (i.e. the UK will have to share it out with other countries). Yet Grundy’s words demonstrate some heated arguments to come – that the Government will no doubt want to avoid with its new testing strategy.

So it is no wonder that the Government is moving away from its initial idea. Ben Spencer, the Conservative MP for Runnymede and Weybridge and previously a psychiatrist, has recently written about the need for Plan B in the UK’s management of Covid-19. He tells me: “I really hope we are successful in inventing a vaccine that helps and saves lives, but we have to make plans on the basis that there won’t be one, or at least one which isn’t a game changer.”

“Although it’s difficult picking apart the figures for flu alone, it’s worth remembering that in 2019, 26,000 people died from influenza and pneumonia, despite having an effective vaccination programme in place for the flu in the UK.”

It seems that the need for another plan is what the Government has sensed, and that’s why it has gone for a new strategy, having had to navigate such difficult areas. It’s clear that the vaccine isn’t the silver bullet many of us imagined. The quickest way the Government can avoid the horrible political scramble that is about to emerge is spurring on its new programme. The pressure is on…