By Pasha Yuen
Get Vaccinated!
National Immunisation Awareness Month is an annual campaign, aiming to raise awareness of the public the importance of vaccination. General awareness of the importance of vaccination has increased substantially following the COVID-19 pandemic. In the UK, the NHS has established an Immunisation Schedule which reminds people when to get a compulsory vaccination, and what optional vaccinations are available.
Several changes have been implemented in recent years, to ensure people are having the vaccinations they needed. For example, in September 2019, Human Papillomavirus (HPV) vaccinations have been extended to both girls and boys aged 12 to 13 years old.
During the COVID-19 pandemic, the UK NHS issued several “Vaccine Updates” regarding the evolving state of the pandemic, including the implementation of the step-by-step COVID-19 vaccination programme in 2021 based on associated risk with different groups (e.g., age, health conditions, occupational group at higher risk of exposure) and booster vaccination programme against various COVID-19 variants.
Other changes have also been implemented during the pandemic; the neonatal Bacillus Calmette-Guérin (BCG) immunisation programme in 2022, and a new vaccine available for the shingles immunisation programme in 2023.
Recently, the UK’s Health Security Agency has announced the Respiratory Syncytial Virus (RSV) Immunisation Programme. Starting from the 1st of September 2024, people aged 75 to 79 years old, or women who are at least 28 weeks pregnant, are eligible for a single dose of RSV vaccine. Check the NHS website for monthly updates information on the national immunisation programme.
Vaccines and Immunisation
Vaccines are a preventive measure against certain diseases. The usual way of making them is to synthesise tiny amounts of specific parts of the pathogen, such as inactivated viruses that have either been killed or are in a weakened form. These pathogen components are attached to a backbone structure, usually one that has been tried and tested for many years, and formulated into a vaccine that can be administered. The most common route of administration is by injection, either intramuscularly or subcutaneously. In some cases, vaccines can also be given intranasally or orally, depending on the desired site of immunity.
The body will recognise the tiny amounts of pathogen in the vaccine, which will trigger an immune response so that antibodies can be produced against these components. During this immune response there may be a fever, which is a normal reaction to vaccination and does not mean the inactivated components have caused any infection.
Upon being exposed to the same components of this pathogen during an actual bacterial or viral infection in the future, our immune cells would immediately recognise the invading pathogen as they have already been exposed to it during vaccination. This prevents the normal delay while the body works out how to fight the infection. Vaccination helps the immune system to “remember” the pathogens, and thus be able to produce the corresponding antibodies quickly to fight the infection. This can mean the pathogen is cleared by the immune system without the infected individual even realising, or the infection may be much less severe and clear much more quickly than it would have without vaccination.
You can learn more about vaccines on the WHO website: Vaccines and immunization: What is vaccination? (who.int)
The Importance of Vaccination
The aim of vaccination is to help you develop immunity against fatal or serious diseases. In addition to protecting yourself, having a vaccine will also help stop the spread of diseases. Having enough people vaccinated can help to develop herd immunity.
Herd immunity is when the proportion of a population with immunity against a disease is large enough to prevent infection from spreading in that population. This can benefit everyone, but it is particularly important in protecting those with weakened immune systems, who would not have been able to receive a vaccination or who may have not mounted a sufficient immune response. Such people include those born with congenital immune system disorders, those on chemotherapy, and those who are pregnant, where the outcome of infection could be extremely severe or even fatal. By vaccinating the majority of the population we can reduce the risk of those people being exposed to the infection.
Vaccine successes
Smallpox was a deadly disease which was fatal in 30% of the cases. With a global joint effort, an immunisation plan of smallpox was launched by the WHO in 1967, and 20 years later, by 1980, smallpox became the first disease to be globally eradicated. Another example of a successful vaccination campaign is Polio, which was eliminated in the UK in the 80s. By comparing the rate of disease prevalence with vaccine availability, we can observe a decreasing trend of people being infected. We most recently observed this during the COVID-19 pandemic.
Vaccine Safety and Signal Evaluation
Monitoring the safety profile of vaccines is very specialised and differs from the monitoring for other products. This is partly due to the way vaccines are manufactured, making the batch number much more important than it might be for other products, and also because they are given to healthy individuals to provoke immune responses in the absence of any illness, making the benefit-risk profile a key consideration.
Health authorities in different countries have their own vaccine safety surveillance plans, with various systems for signal reporting and evaluation. In the following blogs in this series, we will explore the safety considerations for each of the vaccine categories.
Stay tuned for our next blog of the immunisation masterclass, in which we will cover the topic of oral vaccines, what are they for, why choose oral administration over injection, and the safety profile of oral vaccines.
Reference
Smallpox : a history / S.L. Kotar and J.E. Gessler. | Wellcome Collection
UK aid to help vaccinate more than 400 million children a year against polio – GOV.UK (www.gov.uk)
