The first effective coronavirus vaccine to be tested in humans has shown extremely promising results in its preliminary analysis, and appears to prevent more than 90 per cent of people from getting COVID-19. It has been hailed as 'a great day for science and humanity' by its developers Pfizer and BioNTech, and both public and politicians across the world have greeted the news with much hope and excitement. Plans are being made to now make it available by the end of 2020 but it will be well into next year before the majority of the UK is able to be protected from the virus with it, simply because of the huge numbers involved.
A new vaccine is usually developed after many years of research and trials, so to create one in under a year would be a huge scientific feat as no vaccine has gone from conception to completion in such a short timescale. Nonetheless, this is what scientists appear to have done – and with good reason. With COVID-19 (caused by the virus officially known as SARS-CoV-2) now responsible for more than 1.3 million deaths worldwide (more than 50,000 of which are in the UK), the race has been on for months to develop a viable vaccine in the hope that lockdowns can be lifted safely and social distancing measures eased in the near future.
• RNA vaccines
Although the Pfizer vaccine was the first to be announced as being a potentially game-changing vaccine, two more have followed close on its heels. The second was similar to it and made by the company Moderna, again with an effectiveness of over 90 per cent. Moderna's vaccine appears to be easier to store as it remains stable at minus 20C for up to six months and can be kept in a standard fridge for up to a month whereas Pfizer's vaccine needs ultra-cold storage at around minus 75C, but it can be kept in the fridge for five days.
The Pfizer and Moderna vaccines are called RNA vaccines which is a novel technique that takes part of the genetic code of the COVID-19 virus, coats it in a lipid (fat) so it can enter body cells and is then injected into the patient. The vaccine enters body cells and gives them instructions to produce the coronavirus spike protein, which in turn prompts the body's immune system to produce antibodies and activate killer T-cells to destroy cells infected with COVID-19.
• The Oxford Uni-AstraZeneca vaccine
The third to be announced - and one which has some significant advantages over the new RNA vaccines - is the 'Oxford Uni-AstraZeneca' vaccine (developed by the University of Oxford), which is a more conventionally developed genetically modified vaccine. More accurately called ChAdOx1 nCoV-19, this has been created from a virus (ChAdOx1) that’s a weakened version of a common cold. It’s infectious to chimpanzees, but has been genetically modified so that it cannot develop in humans.
Small sections of SARS-CoV-2 have been added to this harmless virus, to create a safe virus that looks like the novel coronavirus. Although the reported overall effectiveness is lower than the RNA vaccines - at around 62-90 per cent depending on the dosage regimen - it can be stored at a regular fridge temperature and is significantly cheaper with a price of around £3, far less than Pfizer's (around £15) or Moderna's (£25) vaccines. Because it uses well-established technology, it can be scaled up and be mass produced quickly and cheaply too for global distribution. The UK government has pre-ordered 100 million doses of the Oxford vaccine, and AstraZeneca says it will make three billion doses for the world next year at a not-for-profit level.
How do vaccines work?
A vaccine works by stimulating a person’s immune system to create antibodies that will fight a particular disease, as if they’d actually contracted it. Developing a vaccine is a balancing act: it must create enough of a response for the body to produce the antibodies, but not so much that the immune system goes into overdrive and creates unwanted side effects.
Once a vaccine has created antibodies, these will be able to fight a disease should the person ever come into contact with it for real. For a vaccine to be approved, it must be deemed safe for everyone to use, including children and the elderly.
There are still many more vaccines currently in the final stages of testing (known as Phase 3 trials) but these vaccines are the first where results have been published so far, all with no reported significant serious safety issues. Although the exact effectiveness of the vaccines may change either way once their full results are analysed, they cannot be used in any national vaccination campaign until the UK regulatory authority - the MHRA - has approved it although this approval is expected to be given very soon.
What is herd immunity?
If enough people within a population are protected by a particular disease through vaccination, it stops the disease from being able to circulate within that community. This is called ‘herd immunity’, and it helps to protect those who are unable to have the vaccine, including babies who are too young to be vaccinated and those with serious health conditions.
Herd immunity only works if the majority of people within a community are vaccinated.
Once a vaccine is developed for SARS-CoV-2, and if enough people are able to be vaccinated, the spread of the virus would likely slow as herd immunity began to have an impact although figures suggest this may take a very long time to achieve currently if no vaccine were available.
It is believed that two thirds of the global population need to be immune to the virus in order to prevent it spreading easily so in effect this means vaccinating billions of people on the planet in order to get to this level.
Other coronavirus vaccines being developed
Vaccines can be developed in several ways. These include whole virus vaccines (which involve giving someone a weak or dead form of the virus that causes the disease) and recombinant vaccines (which do not contain live pathogens).
Recent data on a vaccine being developed in Russia - known as Sputnik V - has also shown promise as this is also in the later Phase 3 stages of its trial and has suggested an efficiency of over 90 per cent. Others are also in the final stages of testing at centres in China and America although one trial in Brazil has been suspended because of a severe adverse reaction in a volunteer.
How far away is a vaccine programme?
A limited number of people in the UK may be able to get some form of vaccine this year but it will probably be January 2021 before any full-scale vaccination programme is rolled out, and it is likely that older residents in care homes and care workers in those homes will be given initial priority to be vaccinated. However, this decision will depend on how well the vaccine works in the very elderly and it remains likely that people under the age of 50 who are fit and well with no medical problems will be vaccinated last.
If the Oxford/Astra Zeneca vaccine proves to be successful, the company has agreed to supply around 100 million doses to the UK and up to 3 billion globally.
Current COVID-19 guidelines
While a coronavirus vaccine may be getting close, it remains important to follow Government advice to help prevent the spread of COVID-19. This includes:
✔️ Adhere to social distancing regulations (stay two-metre away from others outside of your household).
✔️ Frequently wash your hands with soap and hot water, for at least 20 seconds (the time it takes to sing Happy Birthday).
✔️ Avoid touching your face.
✔️ Use hand sanitiser regularly if you need to go out.
✔️ Maintain the two-metre social distancing rule.
✔️ Stay home if you develop a cough, flu-like symptoms or high temperature.
Last updated: 25-11-2020
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