A third UK Covid vaccine has entered phase three clinical trials

A third Covid-19 vaccine will enter large scale clinical trials in the UK today (Mon 16 Nov), to be received by a total of 6,000 volunteers.

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The new vaccine is modelled on an Ebola jab, and is in phase three of testing. It will join two other large clinical trials currently underway in the UK - the first known as the Oxford Covid vaccine, and the other by US biotech company, Novavax.

The 6,000 volunteers will be based in 17 sites across the UK, including Bristol, Dundee, Cardiff, Belfast, Leicester, London, Manchester, Sheffield and Southampton.

What is a phase three trial?

The new vaccine is currently being developed by global pharmaceutical company, Janssen - a subsidiary of medical device company, Johnson & Johnson.

Phase three trials are designed to demonstrate the safety and effectiveness of the vaccine in the typical patient likely to use it.

The trails will also look to confirm dosing levels, identify possible side effects or reasons why the treatment should not be given to people with another condition, and build knowledge of the benefits of the vaccine.

The vaccine underwent smaller phase one and two trials, and analysis of a single dose study suggests that it induces a robust immune response and is generally well tolerated.

How does this vaccine work?

The Janssen vaccine is similar to the Oxford vaccine, using a weakened common cold virus to deliver instructions for making the coronavirus’s surface spike protein to our cells.

Cells infected by the virus begin making the viral protein and trigger an immune system response and expressing it on their surface. There is also the development of “memory” immune cells, which should protect against future coronavirus infections.

The weakend common cold virus is called an adenovirus, and has been modified so it can longer multiply or cause disease. This was the same virus that played a key part of the Ebola vaccine, deployed in 2019 after the outbreak in the Democratic Republic of the Congo.

Need for large scale trails

Despite the news of the 90 per cent success rate of the Pfizer and bioNTech vaccine, the chair of the UK vaccine taskforce has expressed the need for large scale trials of multiple vaccines.

Kate Bingham said, “The recent news is enormously exciting for the whole world, but we must not take our focus off continuing the important research to work out which vaccines work best for different people to provide long-lasting, effective protection against Covid-19.”

So far, around 25,000 people in the UK have participated in Covid-19 vaccine trial, with 310,000 more indicating their willingness to participate in trials after signing up to the NHS vaccine research registry.