Immunity in the Community : Dr Georgia Perona-Wright, Dr Katie Brooks and Dr James Brock
Kelvin Probus had the pleasure of hearing Glasgow University’s Immunology Team giving an informed talk on Vaccines and Immunity in the Community. Members were delighted that our speakers Georgia, Katie and James spoke at a level suitable for a lay audience. Cardiff Castle and IKEA and were entertainingly used in a metaphorical way to effectively give an ‘Immunology for Dummies’ session. Georgia explained how vaccines work and insights on the different vaccines in use. Katie described the vaccine testing procedures and basically reassured members that no corners had been cut in the process. Lastly James provided practical insights gained from the vaccine trials addressed at immunosuppressed patients.
Georgia started the ball rolling by saying that she is a pro-vac fanatic. How else could it be when deadly diseases such small pox had been eradicated and diseases like Polio and TB had been brought under control? The failure of the anti-vaxxers to recognise that vaccines are a tool for controlling and possibly eliminating the pandemic is a mystery. Georgia explained that the basic principle of vaccines is to help people’s immune systems work better to keep bacteria and viruses at bay.
A photo of Cardiff Castle was used to explain the elements of the body’s defence system. The structural defences are similar to the stone walled fort at the top of a steeply sloping motte surrounded by a high wall. In operation, these are complemented by lookouts and an alert team of foot soldiers. Moreover, there is a Commanding Officer who is versed in how to address threats and knows how to direct the soldiers to deal with them most effectively. In practice these foot soldiers will have received training to enhance the effectiveness of responses. This training also benefits from lessons learned from previous events. Last but not least all this adds up to team work which amplifies all the training and lessons learned.
When the body is attacked by bacteria and viruses, the body’s anatomical defences are represented by the castle and its walls. The immune system responds like the foot soldiers desperately throwing buckets of tar, oil and stones at an attacking enemy. As lessons are learned the response is targeted to be more effective. Vaccines provide training to the body’s immune system so that on the next exposure to an infection, it responds more quickly, stronger and more effectively. A simple but elegant metaphor for the manner in which the body’s immune system works.
So far in the UK three vaccines are approved, Pfizer, Moderna and Astra Zeneca. The first two are mRNA vaccines and the last is a Viral vector vaccine. All these vaccines target the spike protein in Covid-19. The spike latches onto the ACE2 receptor in human cells found in the lungs. This spike ‘turns the lock’ of the host cell allowing the virus to enter and then proliferate, causing the infection to take hold.
Georgia explained that the antibodies are made by one of our blood’s white cells. These B-cells secrete antibodies that bind to the spike proteins of the coronavirus and block or reduce the virus’ ability to enter into our blood stream, hence protecting us from infection. The B-cells are helped by T-cells which can also kill any cells that are successfully infected by invading bacteria and viruses. The value of vaccines is that they ‘train’ the B and T-cells to recognise the hostile infections. Summing this up, Georgia described the body as doing a ‘belt and braces’ job. Namely that antibodies are always present in our blood stream are ready to attack invaders and that the B-cells are poised to make more antibodies.
Knowing that the two different UK vaccine types in use, that is the mRNA type (Pfizer and Moderna) and the modified virus type (Astrazeneca) were technically difficult to explain, Georgia, used an amusing IKEA metaphor for her lay audience. She likened the mRNA vaccine to an IKEA instruction manual. Here the host cell is informed by the mRNA vaccine, the instruction manual, to recognise the infection. It then triggers the immune system to attack it. The Astrazeneca modified virus type vaccine provides DNA instructions for the immune system to make RNA to attack the invaders. However, Georgia sees the vaccine more like an IKEA instruction manual in a foreign language which the vaccine ‘translates’ for the immune system. With the translation the immune system can respond effectively. Even this author could grasp these concepts.
Summing up, Georgia observed that while the vaccines may not give 100% protection to the whole population, they are a real source of hope. They will protect you and others from infection and reduce the seriousness of the infection should an individual succumb. However, even with the vaccines, other measures will have to remain for the time being such as the use of masks and social distancing.
Dr Katie Brooks then went on to explain what steps had been taken in testing, ie the safety measures, how this work was done and how it was possible to bring the vaccines to ‘market’ so quickly. Members were reassured that no corners were cut and the vaccine tests were conventionally done despite the shortness of time. There are three key reasons for being able to develop the vaccine so rapidly. The SARS (2002-4) and MERS (2012) outbreaks, also coronaviruses which mean that a lot of research had already been done on coronaviruses. There were high levels of Covid-19 providing lots of infected people to study for further research and clinical trials. And, finally, no time was wasted giving pharmaceutical companies money to do their research and develop vaccines.
Last but not least, and done at a major financial risk, large scale production was started before approval was given. This gave the roll out of the new vaccines a running start. Nonetheless, as indicated, the new vaccines were subject to all the usual development steps, they were thoroughly tested for safety and efficacy and confirmed as safe to use by controlled work across the world.
Dr James Black, joined in at the Q&A session to provide a practitioner’s insight to the ongoing pandemic. He is actively involved in research on Covid vaccine efficacy in immunosuppressed people. James revealed that some people required 3 or 4 doses before they were effectively immunised against Covid-19. Here we learned that making antibodies is ‘expensive’ for the body to produce thus a challenge to those whose immune system is compromised.
It’s not possible to cover all that was discussed in this short blog. However, one interesting aside emerging during discussion on anti-vaxxers and resistance to