60 million doses of the Novavax vaccine will be made in Stockton-on-Tees, after the vaccine was found to be 89.3% effective in large-scale UK trials

So far, the UK has approved three coronavirus vaccines for emergency use; one from Oxford-AstraZeneca, another from Pfizer and BioNTech, and another by Moderna.

How effective is the new Novavax vaccine against the original coronavirus and the new ‘Kent’ variant?

Interim analysis of phase 3 trials of Novavax suggest that it has 89% efficacy, or how well a vaccine works in a controlled trial, against Covid-19. This means that there was 89% reduction in cases of Covid-19 in those who are vaccinated compared with those who received the placebo.

The study involved more than 15,000 participants aged 18 to 84, 27% of whom were over 65. The trial suggested a 95.6% efficacy against the original coronavirus strain, and 85.6% efficacy against the new UK variant. A vaccine’s effectiveness might not be the same as its efficacy. Effectiveness is based on observational studies. When researchers design early clinical trials, they often recruit participants who are generally likely to be healthy. Therefore, they may not include the intended vulnerable group of people who we are aiming to protect initially.

In the real-world, some recipients of the vaccine may be more diverse than study recipients, some will have pre-existing health conditions, or be older than the average trial participant.  Only once the vaccine is deployed will the pharmaceutical companies, such as Novavax, be able to collect sufficient data to determine its effectiveness for different groups of people, under real-world conditions.

How does the vaccine work?

The Novavax vaccine differs from those currently being used in the UK.  The Coronavirus is studded with spikes, made of spike proteins, that the virus uses to enter human cells. Put simply, the Novavax vaccine works by teaching the immune system to make antibodies for the spike protein.

To create the vaccine, the Novavax researchers used a modified gene for the spike protein. They inserted it into a different virus, and allowed it to infect moth cells. The infected moth cells then produce spike proteins that join together to form spikes, as they do on the surface of the Coronavirus.

These spike proteins are harvested from the moth cells and are collected to form nanoparticles,  which mimic the structure of the coronavirus. These spike nanoparticles are combined with a compound extracted made from the soapbark tree to form the vaccine.

When the vaccine is injected into the muscles of the arm, the plant-based ingredient attracts immune cells to the site of the injection, and causes them to attract more strongly to the nanoparticles.

A type of immune cells, called an antigen presenting cell, encounters the vaccine nanoparticles and engulfs them.  The immune cell then tears apart the spike proteins and displays them on its surface. It then recruits other immune cells, called T cells, to help to respond to the vaccine.

If another type of immune cell, called a B cell, has surface proteins to latch onto the spike protein, it can latch on and pull the vaccine nanoparticles inside, and display the fragments of the spike proteins on its surface.

If a T cell, activated against the spike protein, latches onto one of these fragments, it can activate the B cell, which pours out antibodies with the same shape as its surface proteins.

If vaccinated people are later exposed to the coronavirus, their antibodies can lock onto the spike proteins, preventing the virus from entering its cells and causing infection.

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