There were also lower levels of asymptomatic infection in the low-followed-by-high-dose group which “means we might be able to halt the virus in its tracks,” Prof Pollard said.
When will I get it?
In the UK there are four million doses ready to go, with another 96 million to be delivered.
But nothing can happen until the vaccine has been approved by regulators who will assess the vaccine’s safety, effectiveness, and that it is manufactured to high standard. This process will happen in the coming weeks.
However, the UK is ready to press the go button on an unprecedented mass immunisation campaign that dwarfs either the annual flu or childhood vaccination programmes.
Care home residents and staff will be first in the queue, followed by healthcare workers and the over-80s. The plan is to then to work down through the age groups.
How does it work?
The vaccine is a genetically modified common cold virus that used to infect chimpanzees.
It has been altered to stop it causing an infection in people and to carry the blueprints for part of the coronavirus, known as the spike protein.
Once these blueprints are inside the body they start the producing the coronavirus’ spike protein, which the immune system recognizes as a threat and tries to squash it.
When the immune system comes into contact with the virus for real, it now knows what to do.
Are the results disappointing?
After Pfizer and Moderna both produced vaccines delivering 95% protection from Covid-19, a figure of 70% will be seen by some as relatively disappointing.
However, anything above 50% would have been considered a triumph just a month ago and 70% is comfortably better than the seasonal flu jab.
This is still a vaccine that can save lives from Covid-19.
It also has crucial advantages that make it easier to use. It can be stored at fridge temperature, which means it can be distributed to every corner of the world, unlike the Pfizer/BioNTech and Moderna vaccines, which need to be stored at much colder temperatures.
Oxford’s manufacturing partner, AstraZeneca, is preparing to make three billion doses worldwide.
The Oxford vaccine, at a price of around £3, also costs far less than Pfizer’s (around £15) or Moderna’s (£25) vaccines.
What difference will this make to my life?
A vaccine is what we’ve spent the year waiting for and what lockdowns have bought time for.
However, producing enough vaccine and then immunising tens of millions of people in the UK, and billions around the world, is still a gargantuan challenge.
Life will not return to normal tomorrow, but the situation could improve dramatically as those most at risk are protected.
Health Secretary Matt Hancock told BBC Breakfast we would be “something closer to normal” by the summer but “until we can get that vaccine rolled out, we all need to look after each other”.
What’s the reaction been?
Prof Peter Horby, from the University of Oxford by not involved in the trial, said: “This is very welcome news, we can clearly see the end of tunnel now. There were no Covid hospitalisations or deaths in people who got the Oxford vaccine.”
Dr Stephen Griffin, from the University of Leeds, said: “This is yet more excellent news and should be considered tremendously exciting. It has great potential to be delivered across the globe, achieving huge public health benefits.