Saturday, 25 September 2021
DURING the 18th century, the condition known as smallpox killed an estimated 400,000 people a year. If it didn’t kill you, it was still a nasty disease to catch.
That is unless you were a milk maid who had contracted the mild equivalent from her cows and therefore seemed to be immune.
Cowpox, as it was called, was also known as vaccinia (vacca means cow in Latin) and the English scientist Edward Jenner capitalised on the link.
He decided to carry out an experiment that was somewhat ethically suspect. He made a wound in the arm of an eight-year-old boy into which he rubbed cowpox-infected material. After a few weeks he began exposing the boy to smallpox again and again and, fortunately for the boy, he never contracted the more severe condition. Thus the modern concept of vaccination was born.
Much later on, the World Health Organisation ran a successful campaign to eliminate smallpox forever by way of vaccination. By 1980, they were confident enough to declare the disease had been eradicated.
So vaccination is an extremely useful and important tool in medicine and WHO estimates that current levels of vaccination for various diseases prevent about two to three million deaths a year.
What is a vaccine then? It can be defined as something that stimulates the body’s immune system to produce antibodies to a disease without actually infecting us with the disease.
Typically it is a version of the disease itself, either killed or weakened. It could even be individual sections of a virus that the body will still identify as that virus. The process by which the body is made immune or resistant to the disease is known as immunisation.
In order to realistically develop a vaccine, you must first identify the disease itself, be it a virus or a bacteria. The influenza virus, for example, was first identified in the early Thirties and a working flu vaccine followed about a decade later.
Now these annual jabs will target or four strains of the flu virus according to the ones predicted to be the most prevalent through the year. In fact, the flu vaccine is a particularly good one to look at in detail.
This year you will get a different vaccination type according to your age. Anyone in the following groups is encouraged to get vaccinated:
• Children aged two to three
• Children in school years 1 to 5
• Anyone over the age of 65.
In addition, those more at risk from flu complications due to an underlying health condition, such as heart or respiratory diseases, or pregnancy can get the vaccination at any age, as can carers or anyone who works in a medical environment.
The three types of vaccine available at your GP surgery this year are:
• The live version, which comes in a nasal spray and is recommended for children aged two to 17. A live vaccine in this case is one that has been weakened but not destroyed. Shingles and the MMR jabs are also live vaccines.
• Anyone needing the vaccine who is aged 17 to 65 receives an injection in the form of a killed or inactivated vaccine. This is essentially one that contains a virus that has been inactivated using heat or chemicals. Whooping cough and polio are other examples. Despite what anyone says, you cannot get flu from this. There may be a small immune response that mimics a short cold but, I repeat, you cannot catch flu from this vaccination!
• The same goes for the Fluad vaccine, which we use for those aged over 65. As this is a high-risk group, various additives have been included to boost the immune response in the hope that it will be more effective and longer lasting. This type of vaccine is called an adjuvanted vaccine. It can also be said to be trivalent (covering three strains of flu) whereas the ones used for the other age groups are quadrivalent (four strains). The Fluad is being used due to research that has shown it to be more effective in the over-65s.
The flu vaccine is a good example of how the jabs can differ but you may also be aware of the effects should we not vaccinate.
In continental Europe, there is currently an outbreak of measles that is continuing. It is thought that this is due to reduced uptake in the MMR (Measles, mumps and rubella) vaccine, which you should be given at around the age of one with a booster when you are three.
Since the MMR vaccine was introduced in the UK in 1988, measles cases have fallen dramatically — by an estimated
84 per cent between 2000 and 2016.
Unfortunately, due to one study published in 1998 alleging a link between autism and the MMR vaccine, there was a blip in the number of children being vaccinated. This study was carried out on just 12 children and has since been discredited, although the damage had already been done.
WHO aims for around 95 per cent to be vaccinated at the requisite ages and, though we are now back at that target, the figure reached a low of 80 per cent in 2003. As a result, this cohort — now young adults — are still unvaccinated and at risk.
Bearing in mind the situation in Europe, thought to be due to low uptake in countries such as Romania, Greece, France and Italy, measles poses an ongoing risk. There were 274 cases last year and 643 so far this year.
Of course, sometimes a vaccine can be a victim of its own success. It is thought that due to the comparative rarity of measles resulting from the MMR jab, people have become less concerned about getting immunised and so numbers vaccinated have threatened to fall again.
It is therefore important for us all to follow the vaccination programmes recommended to us. No vaccine will be 100 per cent effective but by reducing our personal risk of contracting flu or anything else, we reduce the incidence of a condition as a whole throughout the community. The more people vaccinated against something, the less chance that disease has to spread and multiply through a population. This “herd immunity” is therefore a responsibility for us all to keep up.
So what’s next? At the 2010 World Economic Forum, an initiative was set up leading to the Global Vaccine Action Plan. The aim of this was to prevent millions of deaths from vaccine-preventable diseases by 2020.
The first milestone for this initiative is to eradicate polio in the same way smallpox was eradicated. We are not quite there yet but as rates of vaccination increase, the hope is that many more deaths can be prevented, not just from polio but from all manner of disease. This can only occur if we all buy into the idea.
Ultimately, vaccination works — but only if we allow it to.
• Next time: headaches.
17 September 2018
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