The coronavirus pandemic has changed our lives in more ways than one. However, could the new vaccines be the tool that the world needs to return to normal? There are currently more than 50 COVID-19 vaccine candidates in trials with a number of them, such as the Pfizer-BioNTech, Oxford/AstraZeneca and Moderna ones, already having been approved. So here’s the how, what and why of COVID-19 vaccines.

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What are they and how do they work?

There are potentially four main types of COVID-19 vaccines; whole viruses, protein subunits, nucleic acids and viral vectors.

Whole Virus: This is the most common type of vaccine. It is usually where live or inactive virus cells are injected into a person. These cells cause a small immune response in the body and it is these responses that produce antibodies to help us fight the virus. After the virus has been defeated, some antibodies remain, so that the next time you encounter it, your body will be prepared and able to fight it. However, the live versions of the vaccines may risk producing a large reaction in people with a weaker immune system, leading to possible hospitalization. They often require careful cold storage too, which makes transportation and use in lower-income countries very difficult.

Protein Subunits: Subunit vaccines utilise minuscule pieces of the pathogen (something that can cause a virus) to trigger the immune response. By vaccinating this way it minimises the risk of side effects such as fatigue and headaches. The problem with this type of vaccine however is that the immune response may be weaker, as it may not be producing a sufficient number of antibodies. This is why they often require adjuvants - an agent that improves the immune response of a vaccine - to be effective.

Nucleic Acids: These vaccines use either DNA or RNA to provide cells in our bodies with instructions on how to make specialised antigens. With COVID-19, this antigen is usually the viral spike protein. The antigen is what triggers the immune response inside us. Similar to the whole virus vaccine, it has to be stored at sub-zero temperatures making it unsuitable for less developed countries.

Viral Vectors: Viral vector vaccines are almost identical to the nucleic acid ones. However, rather than using the specific COVID-19 virus, they use a similar DNA to the common cold. This means that we may have already been exposed to the more common type of virus rendering the vaccine useless in the fight against coronavirus.

How have the vaccines been produced so quickly?

Previously, vaccines have taken many years of development to ensure that they are as effective as possible. How have we been able to create so many in just under one year then? A very important factor in getting the vaccine development underway quickly was the fact that the genetic code of SARS-CoV-2 (the coronavirus behind the COVID-19 pandemic) was available in early January. This meant that research teams and companies could immediately get to work crafting their new vaccines, by putting this new genetic code into their existing vaccine platforms.

In addition to this, due to the extreme urgency in making a vaccine, clinical trials have been intensified. This means that in previous years it would have taken much longer to fully test and approve a vaccine for public use. Speed is the key to success with the COVID-19 vaccine, as we are seeing.

Why should we not be afraid to take them?

Many people across the world will be anxious about taking the new vaccine. Perhaps because it has been so quickly made or because they are worried about which one they will receive. One thing to remember is that all of the vaccines have been through processes scrutenising them; they have been tested over and over again. When you get the vaccine you will receive something that has been made to the highest standards possible. You can rest assured that you are in safe hands.