9 in 10 respond to Valneva COVID-19 vaccine in early trials

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Valneva’s inactivated whole virus COVID-19 vaccine is scheduled to enter large scale trials later this month after it was shown to be safe, inducing a strong immune response in its first trials involving 153 people.

The specialist vaccine company Valneva has announced promising results for the first of two parts of its phase 1/2 trial of a COVID-19 vaccine, with two injections of the highest dose generating levels of virus-neutralizing antibodies higher than those seen in patients recovering from COVID-19 infection.

“Again, the people of Southampton have stepped up and contributed to these results that open the way to yet another effective coronavirus vaccine. Having a range of vaccines is vital to tackling COVID-19 now and over the next few years – these latest results are great news, indicating outstanding efficacy for a completely different type of vaccine.

“I want to thank the people of our city and region for their continuing commitment and contribution to these trials,” comments Prof Saul Faust, Southampton lead for the VLA2001 trial and Director of the NIHR Southampton Clinical Research Facility.

Using the whole virus

The Valneva vaccine VLA2001 is different to the other Sars-COV2 vaccines currently in use or in trials. Whilst those vaccines, including Oxford/AstraZeneca, Moderna and Pfizer target the virus’ characteristic spike proteins that help it attach to and enter cells, VLA2001 uses inactivated whole virus.

One of the most established and oldest vaccine technologies, whole virus inactivation has been successfully used in a range of infectious diseases, including polio, hepatitis, rabies and influenza. To boost performance, Valneva used a strain of SARS-CoV-2 rich in spike protein to make VLA2001, and combined this with two adjuvants (alum and CpG 1018) compounds that enhance the immune reaction.

153 healthy adults aged 18 to 55 years were given two injections of the vaccine three weeks apart. They were split into three groups to compare the effects of low, medium and high doses. The trial is being conducted in two parts, Part A (Day 1 to Day 36) and Part B (Day 37 to Day 208).These results are only for Part A of the trial, with the results from Part B yet to be announced, and the results have not yet been formally peer reviewed.

Strong immune response

More than 90% of all study participants produced significant levels of antibodies to the SARS-CoV-2 virus spike protein. No concerning side effects were found, with the majority of side effects either mild or moderate.

The high dose group showed the best immune response, with similar levels of neutralising antibodies to those seen in people recovering from the virus. This dose will therefore be used in the next larger scale phase 3 trial.

Why do we need more vaccines?

More COVID-19 vaccines will help to boost supply and accelerate the vaccine roll-out across the UK, give options for tackling new variants, and prepare for the likely need for regular booster vaccinations.

A Phase 3 trial, involving thousands of people from a greater spread of ages, is expected to start later this month, with the results announced in the Autumn. Success in that trial would pave the way for approval by the UK medicines regulator, the MHRA, and use of the vaccine in the NHS vaccination programme.

VLA2001 would also provide some protection from import and supply chain challenges, due to its production at a new site in Livingstone, Scotland.

Posted on Friday 9 April 2021