For most, vaccines are a welcome addition to routine care, but for some they are perceived as dangerous and threatening. In this blog, we hope to illustrate how vaccines contribute to the health of the population and we will start with their role in cancer control. The human papilloma virus (HPV) is now recognised as the principle causative factor in cancer of the cervix, anus and oropharynx (mouth and throat). Because this virus is an infective agent that raises antibodies, its effects can be prevented by vaccination, and thanks to the development of an effective vaccine by Ian Frazer and his group in Australia the virtual eradication of these cancers is now a possibility. In the UK, all girls and now boys aged 12 to 13 in school year 8 are offered HPV vaccination. With high adherence to this programme, it is anticipated that cervical screening will eventually become unnecessary and that suffering from a HPV related cancer will become a thing of the past. However, for this aspiration to be realised, is essential that this protection is extended to the vast majority of the population.
The attention of our community is focused at this moment on vaccination to prevent COVID. The SARS-CoV-2 virus, the cause of COVID, is one of the most contagious infective agents we know of: 1 infected person will typically infect 5-6 other people, three times more infective than ‘flu. As no-one has any pre-existing immunity to the virus, the disease can be severe, and as we have discovered in the last 12 months, can be fatal. Public health measures of social distancing, mask wearing, hand hygiene have certainly helped reduce spread, and have almost eradicated the transmission of ‘flu this year. Travel restrictions and ‘lockdowns’ have been necessary to keep the numbers of cases down. The best chance we have of a return to ‘new normal’ is mass vaccination of the population.
SARS-CoV-2 is similar in structure to SARS, and MERS, two other coronaviruses that caused outbreaks of respiratory illness in 2002 and 2012. Since these two epidemics, teams of researchers have worked to try to develop a vaccine against coronaviruses, with some early success. The COVID pandemic brought together scientists, doctors, and the pharmaceutical industry to develop rapidly those initial vaccines, get good quality trial data, and manufacture enough to vaccinate the population. The are, broadly, two kinds of vaccine: a ‘traditional’ vaccine (Astra Zeneca) where the SARS-CoV-2 protein is spliced onto an inert virus that causes no disease in humans; and an mRNA vaccine (Pfizer, Moderna) that uses the body’s own protein making ability to generate the SARS-CoV-2 proteins, rather than injecting them directly. Both vaccines have been shown in clinical trials to be safe and highly protective against COVID disease.
Some people have been very worried about the safety of the vaccines, particularly because it seems like they have been developed ‘too quickly’. In reality these vaccines have been in development for at least a decade, with a huge amount of the important scientific work done by research teams over many years. All the vaccines have been through rigorous clinical trials, they have been approved for use by the regulatory authorities, and surveillance of everyone who gets the vaccine is thorough.
There have been reports of adverse reactions to the vaccines, some of them have led to conflicting changes in vaccination policy across Europe: it’s confusing to know what’s the right decision. The rates of complications remains very small – significant allergic reactions have been reported in about 20 people per million vaccines, with no deaths; the risk of a significant blood clot is around 10 per million vaccines given to people under 30, falling to around 2 per million vaccines given in people over 60. The risk of being struck by lightning is around 1 in a million, for comparison. What we do know is that the benefits of vaccination are very compelling: COVID disease is reduced by over 90% in people who have had a vaccination and a booster; 1 million vaccinations reduces ICU admissions by 140 every 16 weeks; early data suggests that vaccination reduces the spread of COVID, protecting other people in our communities who have yet to be vaccinated.
On the 12th April 1955 Jonas Salk’s polio vaccine was approved for use, leading to a dramatic, and long lasting, reduction cases of polio worldwide. 66 years later the same underlying principles of immunology, and decades of advancement of vaccination technology have us on the brink of controlling an infection that has dominated and controlled our lives for over a year. To reach the much talked about ‘herd immunity’ we need to vaccinate 82% of the population – I strongly encourage you to roll up your sleeve when you are invited to receive the COVID vaccine, and once you have to stick with the FACTS guidance until everyone has been vaccinated, to protect yourself, your loved ones, and everyone in our communities.
Dr Tom Fardon is a consultant Physician in Respiratory and General Internal Medicine at NHS Tayside, Honorary Reader with the University of Dundee, and Associate Postgraduate Dean for the East of Scotland Region of the Scottish Deanery.