Covid 19: The hope for a vaccine

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Covid-19, otherwise known as the coronavirus, is an infectious illness that has affected the lives of billions worldwide. With the case of COVID-19, the virus penetrates deeper within our respiratory system, causing more cells to become inflamed, and this triggers a fluid build-up in the lungs. These fluids will contain residues of lots of cells, resulting in the beginning of a very known symptom of coronavirus – coughing. Since the lungs become full of fluid, and the number of infected air sacs increases, it becomes more difficult for oxygen to be removed from the air so gas exchange can take place, resulting in breathlessness.

As of now, there is no vaccine that has passed all stages to deem them safe. Any breakthrough with a vaccine would be used with immediate effect, if all stages are passed, with key workers and older populations prioritised for the vaccine to ensure safety. This would eventually be spread to the global population preventing infections from spreading, as well as bringing lives eventually back to normal with little risk. While there is still a long way to go before this can happen, there is hope of a potential vaccine that has recently come into light: ChAdOx1 Vaccine, which is now undergoing testing in phase 3.  

ChAdOx1 nCov-19, a genetically engineered vaccine, has proved to be very promising already from trials, where its injection to 1077 people resulted in the production of antibodies and T-cells that fight coronavirus. Antibodies and T-cells are part of the immune response, with the antibodies attaching to the surface of viruses to neutralise pathogens, preventing them from carrying out their function and T-cells being involved in killing already infected cells with viruses present. As a virus that originally caused the common cold in monkeys, it has been safely modified so that it cannot cause any infections but still produces an immune response, as with all vaccines.

A vaccine is traditionally developed through multiple stages:

  • Exploratory stage/ research (2-5 years)
  • Pre-clinical stage (2 years)
  • Clinical development (9-15 years)
  • Review and approval (2 years)
  • Manufacturing
  • Quality control

Within these stages, there are three phases to clinical development, where the number of groups starts off very small in phase 1, to then increasing the number as well as choosing certain characteristics, including age and health in phase 2, to finally being tested on thousands of people for safety in the last stage. As seen by above, a normal vaccine can take more than 10 years of rigorous testing to be developed. However, with the situation that the whole world is in right now, 10 years is too long for the vaccine to be produced and this is why things are going very differently. So, what changes have taken place for vaccines to be developed so quickly?

Initially, a huge investment was required for multiple vaccines to be produced. This would mean billions of pounds being spent, with some being wasted on failed vaccines, but this would be required so that any potential vaccine could be developed as soon as possible. The next step would have been to research and develop up to 100 potential vaccines in a few months, with the promising candidates then being funded for further development, being narrowed down to around 10. Currently, most potential vaccines are undergoing clinical trials, taking only 4 months to progress to phase 3 for something that normally takes 15 years. This shows the huge difference and urgency from normal, with only one major vaccine that then passes all trials prepared for manufacturing and delivered throughout the world.

A different treatment being used already in some hospitals is dexamethasone, a steroid which reduced the mortality rate for patients requiring help for breathing, such as ventilators or oxygen. Although it didn’t affect any patients who weren’t on respiratory support, trials estimated that it decreased the number of deaths by one third in patients with ventilators, and one fifth for people receiving oxygen. They work by decreasing inflammation, and stopping the immune response as much as possible, reducing damage to the lungs. However, there is also some risk that it may stop the immune system from functioning properly at all, making the patient vulnerable to secondary infections so proper maintenance must be kept.

As winter soon approaches, people are expecting the worst, with a second wave most likely as cases start to rise again. The hope of vaccine will intensify, with estimates that it may be ready by early 2021.


References

  1. Wellcome “How can we develop a Covid-19 vaccine quickly?” [online] Last accessed date: 22/04/2020 <https://wellcome.ac.uk/news/how-can-we-develop-covid-19-vaccine-quickly>
  2. Lancelot “Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2” Last accessed date: 20/07/2020 <https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31604-4/fulltext
  3. University of Oxford “Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2” Last accessed date: 20/07/2020 <https://www.research.ox.ac.uk/Article/2020-07-20-safety-and-immunogenicity-of-the-chadox1-ncov-19-vaccine-against-sars-cov-2-a-phase-i-2-randomized-control-trial
  4. BBC news “Coronavirus: Oxford vaccine triggers immune response” Last accessed date: 20/07/2020 <https://www.bbc.co.uk/news/uk-53469839>
  5. CDC “Vaccine Testing and the Approval Process” Last accessed date: 01/05/2014 <https://www.cdc.gov/vaccines/basics/test-approve.html
  6. “How does the immune system respond to a coronavirus attack?” Last accessed date 21/04/2020 <https://www.thehindu.com/sci-tech/health/coronavirus-how-does-the-immune-system-respond-to-a-coronavirus-attack/article31319716.ece

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