Life moves pretty fast – and so does science. Less than a year after we first heard of Sars-CoV-2, the coronavirus that causes Covid-19, there are already a number of vaccines in the final stages of approval (and hundreds more at varying stages of development). Thanks to the Trojan efforts of academia, industry, and willing volunteers, the rollout of a vaccine against the virus that has blighted all our lives is now imminent, and an end to the pandemic is finally in sight.
Perhaps more than any other medical innovation, vaccines have transformed the face of modern medicine. They continue to save up to three million lives each year worldwide from a wide range of infectious diseases, such as hepatitis, diphtheria, tetanus, whooping cough, measles and polio.
But how exactly does a vaccine work, and why are the latest batch of vaccines different to those we are used to receiving for other diseases? How exactly does a vaccine trick the body’s immune system into fighting off infection? A new podcast aims to shed light on all the burning questions we are certain to have about the most important vaccine in a generation.
Listen to Speed of Science podcast now, supplied by Science Gallery Dublin:
The first episode, entitled Personal Immunity, sees Science Gallery Dublin mediator Cillian Gartlan talking to Dr Clair Gardiner and Dr Fred Sheedy from Trinity College Dublin about the vaccine development pathway and the types of vaccines scientists are now able to create using the latest technology.
Sheehy, Ussher assistant professor at the School of Biochemistry and Immunology, explains that a vaccine is a “lesson, educating your immune system”. “It’s teaching your immune system a very specific language,” he explains on the podcast.
The vaccines we are most familiar with – such as those against polio, measles, or mumps – typically contain a modified version of the pathogen in question. Known as “live” vaccines, these contain just enough to allow the body to mount an immune response to it, without actually developing the disease it causes.
Clinical trials are diligent in recording any possible side effects of the vaccine and this work will continue long after it is made available.
“You are building up that arsenal of weapons that you need … if you ever encounter the pathogen in real life in its dangerous form, you have everything ready to fight it and you’ll be able to clear it without causing too much harm,” Gardiner, professor of biochemistry at the School of Immunology, explains.
The super strong immune response elicited by these vaccines mean that they are extremely effective, but the downside is that they simply aren’t suitable for everyone. For example, people who are already immunocompromised may develop the disease after receiving a live vaccine. This has happened in the past, with dire consequences, Gardiner says.
Advances in biotechnology, however, mean that it is now possible to develop vaccines that will be safer. “Subunit vaccines” use just part of the pathogen in question, the part that is most impactful in terms of inducing an immune response. While these are not as effective as their live counterparts, they are infinitely safer, and Gardiner adds that their effectiveness can ultimately be enhanced in a number of ways.
Yet, according to Sheehy, the big issue is defining what a good immune response is and defining what protection involves. This will be critical when it comes to vaccinating against Covid-19 and ultimately controlling the pandemic.
“What does it mean to be protected? Does it mean you never get sick, or you get a little bit sick, or don’t pass it on? Does it mean you have antibodies?” All vaccine trials thus involve regular follow-ups to monitor a person’s response. For example, some vaccines may require a “booster” dose, to enhance its activity.
What we do know is that the human immune system has an excellent memory, and it is also highly adaptive. Indeed, there has been much focus on the presence of antibodies following infection with Covid-19 – specific proteins produced following infection that lock onto foreign invaders within the body and tell the immune system to get to work. But immunity may also be mediated by cells known as T-cells, which effectively kill off infected cells.
“The beauty of the immune system is that if you ever encounter that particular pathogen again, you won’t get sick as you will have built up all the resources you need to fight against that particular pathogen,” explains Gardiner.
Safety is of the utmost importance, both scientists stress; clinical trials are diligent in recording any possible side effects of the vaccine and this work will continue long after it is made available.
Speed of Science
All this and much more is discussed in the new podcast series, which is being released in tandem with a new digital-led initiative by Pfizer and Science Gallery at Trinity College Dublin, Speed of Science.
The initiative tells the historical story of vaccines and the role of scientific advancement in society. Passers-by will be able to get a glimpse of new exhibit through the windows of Science Gallery Dublin on Pearse Street, which will feature a compelling installation. The initiative takes the viewer on a journey through scale; moving from personal immunity, to examining how the body responds to vaccination, through a local scale looking at community immunity, to a global scale – demonstrating the transformation of societies and health systems through vaccinations.