'The scientists have done it': Boris Johnson hails Covid vaccine

Boris Johnson has declared that the nation is no longer resting on the hope of a return to normality by spring but instead has the “certain knowledge” that people can reclaim their lives, as he hailed the arrival of the newly approved Covid-19 vaccine.

The prime minister told a Downing Street press conference on Wednesday that “the scientists have done it”, although he stressed that people should not get carried away with “over-optimism”, insisting that they continue to abide by the rules.

The UK is the first western country to license a vaccine against coronavirus, and mass immunisation is expected to begin next week. The Pfizer/BioNTech vaccine has been authorised for emergency use by the Medicines and Healthcare products Regulatory Authority (MHRA) before decisions by the US and Europe.

Related: When and how will I be able to get a Covid vaccine in the UK?

Striking an upbeat tone, Johnson said: “We’re no longer resting on the mere hope that we can return to normal next year in the spring, but rather the sure and certain knowledge that we will succeed and together reclaim our lives and all the things about our lives that we love.”

He added: “We have been waiting and hoping for the day when the searchlights of science would pick out our invisible enemy and give us the power to stop that enemy from making us ill. And now the scientists have done it, and they have used the virus itself to perform a kind of biological jiu-jitsu, to turn the virus on itself in the form of a vaccine.”

There were still “immense logistical challenges”, he said. “So it will inevitably take some months before all the most vulnerable are protected. Long, cold months. So it’s all the more vital that, as we celebrate this scientific achievement, we’re not carried away with over-optimism or fall into the naive belief that the struggle is over.”

As England entered a new strengthened tiered system of coronavirus restrictions on Wednesday, Johnson pleaded with the public to stick to the rules.

Speaking alongside him, the deputy chief medical officer, Jonathan Van-Tam, said he had become emotional watching that morning’s press conference announcing the vaccine’s approval. “And what a momentous … journey and international effort it has been,” Van-Tam said. “Discovery by two scientists who originally lived in Turkey, development by a German biotech company, involvement of a massive US pharmaceutical giant, and then involvement of our own UK MHRA to bring home the goods.”

However, he too cautioned that the rollout would take months rather than weeks, and that restrictions including social distancing must stay in place. “If we relax too soon, if we just kind of go, ‘Oh, the vaccine’s here, let’s abandon caution,’ all you are going to do is create a tidal wave of infections.”

Asked whether Johnson was failing to protect the most vulnerable if care home residents did not end up getting the vaccine first, Van-Tam said it was a “complex product” and “really tricky to handle”, explaining: “It’s not a yoghurt that can be taken out of the fridge and put back in multiple times.”

Van-Tam said he did not think humankind was “going to eradicate coronavirus ever”, but we may get to the point where it becomes “a seasonal problem” like flu. He added: “Do I think there will come a big moment where we have a massive party … and say, ‘That’s it, it’s behind us,’ like the end of the war? No, I don’t.”

Johnson responded: “That may be a good thing ... on the other hand, we may want to get back to life as pretty much as close to normal.”

Related: UK coronavirus live: Johnson confirms it will take months until most of vulnerable group are vaccinated

The UK has purchased 40m doses of the Pfizer jab – enough for 20 million people, as it is administered with two injections 21 days apart. The vaccine, which must be stored at -70C, complicating distribution, has been shown to have 95% efficacy in its final trials. An initial 800,000 doses will be made available next week, and millions more will follow in the coming weeks.

It will be rolled out in order of priority, starting with care home residents and their carers, people over the age of 80, and frontline health and care workers, before being made available to the rest of the population in order of age and risk, including the clinically extremely vulnerable.