The race to develop a COVID vaccine to protect the world’s population from the potentially devastating virus is one of both winners and losers. This pursuit has seen some tripped up by various hurdles along the way, while others are either in full view of the finish line, or are crossing it.

Earlier this month, the British Government announced the approval and subsequent roll out of the Pfizer-BioNTech COVID-19 vaccine, while the Moderna COVID-19 vaccine received emergency use approval by the US Food and Drug Administration (FDA). Back home, the Australian Government announced it has secured millions of doses of the Novavax and Oxford-Astra-Zeneca vaccines as part of its COVID-19 Vaccine and Treatment Strategy, off the back of the University of Queensland (UQ) abandoning its vaccine development plans after eliciting “false-positive” HIV  results during trials.

To truly appreciate the importance of developing a vaccine to protect the global population against COVID-19, and why scientists are placing so much emphasis on its production, it is critical to initially understand how vaccines work.

This month the World Health Organization (WHO) released an information series on vaccines, endeavouring to heighten public knowledge of such prior to the eventual global roll out of a COVID-19 vaccine.

To learn more about the COVID-19 vaccine, read on.

How do vaccines help the body’s immune defence?

COVID-19, like all pathogens, contains a specific antigen, a sub-part of the virus that causes the production of antibodies. Antibodies are an important part of the immune system’s defence that recognises when a pathogen has entered the body. Each type of antibody, of which there are thousands in the human body, is triggered by a specific antigen to stimulate an immune response and ward off disease.

The body creates antibody-producing memory cells following its exposure to an antigen, to allow for a faster, more effective immune response when next exposed to the same pathogen. However, it takes time for the body to produce antigen-specific antibodies, particularly to new pathogens, such as COVID-19, making it susceptible to developing the disease in the meantime.

This is where vaccines enter the picture.

Vaccines contain a weakened or inactive antigen, or the blueprint for producing antigens, to trigger the body’s immune response. They will not cause the disease in the vaccine recipient, but will rather act as the body’s primary exposure to the antigen, so it can produce the antibodies required to fight any future infections by that pathogen.

Some vaccines require multiple doses to aid the production of long-lived antibodies, and memory cells in training the body to promptly recognise the pathogen and fight the disease. Once the body develops these antibodies however, it can recognise the antigen and fight the infection.

Protecting our global community

Anyone with an underlying health condition that weakens their immune system may be unable to be vaccinated, and will therefore rely on ‘herd immunity’ for protection from pathogens, such as COVID-19. Herd immunity works when a large proportion of a community is vaccinated, making it difficult for a pathogen to circulate among the population, in turn protecting the unvaccinated individual.

Although not a single vaccine, or herd immunity can provide 100 per cent protection against an infectious disease, they can however, provide substantial protection, with the latter particularly helping those unable to be vaccinated.

What’s the development process for vaccines?

Like all vaccines, COVID-19 vaccines are undergoing extensive and rigorous testing to ensure their effectiveness and safety, prior to distribution. Even before clinical trials are performed on humans, meticulous screenings and evaluations determine the appropriate antigen to be used in the vaccine, that is then tested in animal populations. Should the vaccine prove to be successful at this point in time, a three-phase clinical trial process will commence with human subjects.

In each of the three phases, an increasing number of people are vaccinated to ascertain their personal response to the vaccine, and the dose required to trigger an appropriate response, compared to a control. Following the completion of these trials, further regulatory steps must be taken to ensure the developed vaccine is proven safe and effective across a broad spectrum of the population before its subsequent approval for distribution. Once a vaccine is in use, it is continuously monitored to ensure its ongoing safety and effectiveness.

As the world awaits a global roll out of COVID-19 vaccines, greater understanding of how they work will encourage more people to get vaccinated, in order to help protect the global community from this potentially devastating virus.