As COVID-19 continues to spread and claim lives in the UK and globally, the World Health Organization (WHO) continues to collaborate with more than 100 candidates internationally, all of whom are working to develop the most effective and accessible vaccine for the SARS-CoV-2 coronavirus. This global effort to produce a lifesaving vaccine has been described as a race, although it is clear now that more than one vaccine will be needed, given the number of people who will need to access it.
A handful of the candidates have produced particularly encouraging results, and orders are being placed for millions of doses of the potential vaccines by countries around the world. Vaccines developed by Pfizer, Moderna and AstraZeneca are receiving the most attention, although others, such as the Sputnik V vaccine from Russia, are being evaluated by the WHO in Geneva, and large-scale trials are ongoing.
RNA vaccines
The first vaccine in the world that was deemed to be effective in preventing COVID-19 was developed by Pfizer and German biotechnology firm BioNTech, showing a >90% protection rate. It was tested on 43 500 people across six countries, and a preliminary analysis showed that it can prevent more than 90% of vaccinated people from contracting COVID-19 (Gallagher, 2020a).
Two doses are needed, 3 weeks apart, and trial data from the US, Germany, Brazil, Argentina, South Africa and Turkey show that 90% protection is achieved 7 days after the second dose (Gallagher, 2020a). This is based on early data, but the trial has continued and now has enough safety data for regulators to decide on its approval status (Gallagher, 2020a). According to some sources, the NHS could be ready to administer it as early as 1 December 2020 (Donnelly, 2020). Britain has ordered 40 million doses of the vaccine, a quarter of which will be available this year if regulators approve it and would be enough to vaccinate 5 million people, with the bulk being vaccinated in 2021 (Donnelly, 2020; Gallagher, 2020a).
The vaccine from Pfizer and BioNTech is an RNA vaccine, meaning that part of the genetic code of the virus is taken and coated with a lipid so that it can be safely injected; it then tells the body's cells to produce the ‘coronavirus spike protein’, prompting the immune system to produce antibodies and activate T-cells to destroy the infected cells (Gallagher, 2020a). However, an associated drawback of this vaccine is that it is not stable at room temperature and needs to be stored at -80 degrees C until it is administered to the patient.
A similar RNA vaccine to that produced by Pfizer was developed by US company Moderna and showed to be 94.5% effective (Gallagher, 2020b; Heff, 2020). In a trial of 30 000 people, half were given two doses of the vaccine, 4 weeks apart, and the other half were given placebo or ‘dummy’ injections (Gallagher, 2020b). Of the first 95 vaccinated people to develop COVID-19, 90 were in the placebo group, and only five were in the Moderna vaccine group (Gallagher, 2020b). Additionally, 11 severe cases of COVID-19 developed, all within the placebo group (Gallagher, 2020b). Interestingly, around 3000 people in the trial were only given a half dose of the vaccine for their first injection, followed by a full dose for their second, and still achieved a 90% protection rate, meaning there might be much more of the vaccine to go around (Gallagher, 2020b). The UK has not yet secured access to this vaccine but hopes to do so by early spring 2021 (Heff, 2020).
Other vaccines
The world's first registered vaccine for COVID-19 called Sputnik V was announced in August by Russian President, Vladimir Putin, and it is in its third stage of a clinical trial of 40 000 people (Tickle, 2020). It is being evaluated by the WHO after having applied for accelerated official certification (Tickle, 2020), and phase III results suggest a 92% protection rate (Gallagher, 2020a).
In its final stages of testing, a vaccine developed by the University of Oxford and pharmaceutical company, AstraZeneca has shown a 70% protection rate from its early data, but the researchers believe this could be increased to 90% by adjusting the dose (Gallagher, 2020c). While further testing is required, this vaccine would be cheaper to produce and scale up, easier to store and be made more easily accessible to people all over the world (Gallagher, 2020c). Unlike those from Pfizer and Moderna, the Oxford vaccine is a common cold virus that used to infect chimpanzees which has been genetically modified to stop it causing infection in people and to carry the ‘blueprints’ for part of the coronavirus, the spike proteins, activating the body's immune system (Gallagher, 2020c). The UK government has already pre-ordered 100 million doses of this vaccine, with potentially more to come next year (Gallagher, 2020c).
Conclusion
Thus far, the UK has secured early access to six of the candidate vaccines, totalling 350 million doses (Heffer, 2020), and new information regarding potential vaccines is being uncovered daily. Once a vaccine has been approved, trained vaccinators in community pharmacy will be required (Wickware, 2020), and nurses should remain updated on developments in order to continually support, inform and signpost patients accordingly.