Dame Sarah is the Saïd Professor of Vaccinology in the Nuffield Department of Medicine at the University of Oxford. She took us behind the scenes of the AstraZeneca COVID-19 vaccine programme, explaining how it was developed and approved at a pace, while the public waited eagerly for science to find a way out of a global pandemic.

Dame Sarah described how they were able to move so quickly, using platform technology, which means they do a lot of work on the vaccine platform itself before they actually start to use it to develop a vaccine against a specific disease.

She said: “Because so much of the work has already been done, when we decide which disease we want to use it to make a vaccine against, we can proceed very quickly, because we've already answered so many of the questions that need to be answered before we can start to use the vaccine. We've already worked out how to produce the vaccine, how to test it prior to going into clinical trials, how to manufacture at large scale.”

The vaccine was made safe by making into a non-replicating viral vector by removing some of its genes. She explained: “That means that the adenovirus can still infect cells in our body after we vaccinate somebody, and it can make the spike protein inside those cells. But the adenovirus can't then make any more of itself, and it can't spread through the body any further. We've taken out some of the original genes and we put in the genes to encode the spike protein, and then we can manufacture this in large quantities and use it as a vaccine.”

She explained how they had been developing this technology for some years before 2020 and, by April of 2020, had already worked on 12 phase one clinical trials.

Dame Sarah went on to explain the vaccine trial for COVID-19, and the partnership with AstraZeneca. “What we needed to do was go faster and go bigger. We needed a pharma partner because although the university can do some vaccine manufacturing and run clinical trials, we are never going to be manufacturing at the scale that's needed for market supply, and we need a pharma company to partner with us to take on that activity.”

Once the trial was underway, one thing they wanted to know was 'is the vaccine effective at preventing hospitalisation and severe COVID?'. “What we saw is that anybody who'd got to at least 14 days after the second dose of vaccine, there were no hospitalisations in the COVID vaccine group whereas there were in the control group, and there were no cases of severe COVID in that group, which was a very good outcome.

“But then we also reported on the efficacy of the vaccine to prevent symptomatic COVID, not necessarily severe or requiring hospitalisations. We were able to show that up to 90 days after vaccination, there was 70 percent efficacy at preventing symptomatic COVID disease.”

The vaccine that was developed by Dame Sarah and the Oxford Covid vaccine team doesn't require frozen storage, it can be stored in a normal refrigerator, and that means it can feed into existing supply networks that are used for other vaccines. This makes it much easier to use than vaccines that do need to be stored at frozen temperatures. AstraZeneca had also, as well as agreeing to make the vaccine available in very large numbers of doses, made it available not for profit during the pandemic, and for low-income countries even after the pandemic ends.

The research continues with the emergence of COVID-19 variants. “We're also working on updated versions of the vaccine with variant spike proteins. The Beta variant spike is most different from the original spike. Delta is not quite so different, and we don't know if we need to change the spike protein that's in the vaccine. So, we're doing some experiments to test that.”

Dame Sarah ended her fascinating talk by acknowledging the help of so many people that have been important in generating all of this data. “First and foremost, the volunteers that came forward to take part in our clinical trials in very large numbers and have been very patient with us in coming back and regularly giving us samples of their blood so that we could see what the vaccine was doing to them and enabling us to generate the data that means the vaccine can then be licensed and used widely.”

She added: “The work was initiated in my group at the Jenner Institute, but we very quickly joined forces with the Oxford Vaccine Group who took on the running of the clinical trials.

“And of course, I'd like to thank all our funders and our partners in this work. AstraZeneca, who took on a very large programme of work and really invested heavily to make sure that we could have enough vaccine to supply around the world.”

Now, more than 1.3 billion doses of this vaccine have been released. What an immense achievement.

The talk ended with questions from the audience around how the vaccine works, and about vaccine development and rollout. We also had a question about working as a scientist as we had some school students watching. They asked: ‘What advice would you give to school students who want to become scientists?’

Dame Sarah responded: “I think the most important thing is to find the bit of science that really makes you tick. There are lots of different ways of working as a scientist, and there are lots of different aspects of science. And there's also maths, physics, chemistry, biochemistry, biology, lots of different areas.

“Find which bit really makes you tick and then follow that, but don't make your options too narrow, too early. Don't specialise. Wait until you get to university and do a bit of all the different sciences, if you can, and then decide where you want to go from there.”

Sound advice for budding scientists from a brilliant and inspiring researcher. Thank you to Dame Sarah for her fascinating talk.