The first article was about the differences between colds and 'flu. This article will discuss vaccinations and their effectiveness. These are not necessarily my personal opinions, nor those of PSI, nor those of CTA.
Our natural immune system
First, our immune system detects any tiny particles (including viruses and bacteria) that are "not self" to our body. Next, it initiates a range of activities to try to get rid of the "foreigners". Made up of several different groups of interacting specialised cells operating on three levels of complexity, our immune system co-ordinates an orderly process of physical, chemical and biochemical reactions to try to destroy and eliminate any of these "foreign" invaders.
Isn't this amazing? Psalm 139 verse 14: "I will praise thee; for I am fearfully and wonderfully made: marvellous are thy works; and that my soul knoweth right well."
Vaccines work by copying nature in a safe way
Taking advantage of the body's natural way of defending itself, vaccines introduce safe and carefully tested killed or modified micro-organisms (or parts of their outer coat) into your body. All the injectable 'flu vaccines in Australia contain killed (inactivated) viruses. No-one can possibly get the 'flu from the vaccine.
However, the natural immune system recognises the particles in the vaccine as "foreign", and it produces antibodies to neutralise them; the same ones that your body needs to attack the real influenza viruses. Antibodies look like a negative "mould" of the foreign particle, which they sticks to like a lego brick. This marks the invader for destruction by other chemicals in the body. The "goodies" (antibodies) remain in the bloodstream ready to multiply up if they contact that same "baddie" another time, even after the infection has gone.
This is exactly the same way you become immune to some diseases after you have been ill. But vaccines are designed to have a minimum reaction; it is a much safer option than getting sick, yet it produces the same protective antibodies. Vaccination programs also protect the whole community because not so many people will harbour the live "germs" in their bodies. The germs cannot be spread around; public immunisation has avoided many epidemics. (See my previous article on vaccines.)
Some statistics about 'flu from around the world
How effective is a vaccination? The true answer is "it depends". It depends on how strong (virulent) the latest disease micro-organism is, it depends on the natural state of the person's immune system, it depends on whether someone is sick with another disease when they have the immunisation, it depends on which viruses were used to make the vaccine.
Nothing in biology is perfect. Not everyone will get total immunity either from a vaccine or from catching the disease naturally; and some people have a natural immunity. (For example, young relative of mine had chicken pox three times, and her sister, who was with her, didn't get it at all.)
Already, smallpox has been eliminated world-wide; polio is only present in small pockets of inaccessible populations; and very, very few people have ever seen a case of diphtheria or tetanus in our privileged Western world today. These diseases killed many children under the age of five in the past. One of the most recent reports has been that rubella (German measles) has been eliminated from North and South America because of consistent vaccination programs. This is good news – one of my family members is deaf because her mother had rubella.
Careful analysis of statistics over large populations all over the world has shown that effective 'flu immunisation campaigns prevent more disease, more epidemics, and certainly more serious complications resulting in hospitalisation or death, than the natural disease.
Published statistics about the effectiveness of influenza vaccines from various sources indicate that the effectiveness is between 70% and 90%; and it prevents death from secondary complications such as pneumonia in up to 80% of the elderly and infirm. These statistics are variable, partly because the 'flu viruses differ each year, and partly because people report that they had the 'flu after immunisation, but it may have been the common cold (which the vaccination will not prevent).
Why we need a 'flu vaccination every year
There are two main reasons we need a new vaccine for influenza every year, although not for some other diseases. All types of 'flu virus mutate very easily in nature – alterations in their DNA as they multiply makes each generation a bit different from the previous one. Some of these changes make them less dangerous, but a few make them more dangerous, and some may make them easier to catch. Sometimes a 'flu virus that was only in animals, can suddenly change to infect humans too. (Then they are known as "bird 'flu", "swine 'flu" etc).
Because these variations are random, and perfectly natural, there is no way that scientists can predict exactly which viruses to use to make the vaccine for next year. They can just use a "best guess" from the previous winter in the opposite hemisphere.
It is also impossible to include pieces from all of the hundreds of viruses, so only the most virulent three virus types are included to make the vaccine. Medical research has shown that vaccination from these strongest strains gives some partial protection from other related strains too.
The release of the Australian 'flu vaccine was late this year because, during the production phase, the medical scientists found out how to include a nasty strain of the that had been in the USA. They could therefore make the vaccine much more effective, so they worked hard to include the new variety and still have the vaccine ready before winter.
In summary, vaccines stimulate the natural immune system in a safe way. Immunisation programs around the world have been effective at reducing illness, disability and death. Over the past 60 years, vaccines against influenza (the 'flu) have helped reduce or prevent epidemics such as the horrific one in 1918.
Even if not 100% effective, the 'flu vaccine will protect people to some extent, reduce its circulation in the general population, and even reduce the severity of related 'flu strains. Certainly, it helps stop secondary infections and complications. Remember, though, it does not protect you against the common cold, which is a different disease!
Note: These two articles do NOT provide medical advice, they are just scientific descriptions. If you (or someone you are caring for) becomes ill, has trouble breathing, has high temperatures or you are worried about something just not being right, then seek medical advice to get accurate diagnosis and medical intervention.
Dr Mark Tronson is a Baptist minister (retired) who served as the Australian cricket team chaplain for 17 years (2000 ret) and established Life After Cricket in 2001. He was recognised by the Olympic Ministry Medal in 2009 presented by Carl Lewis Olympian of the Century. He mentors young writers and has written 24 books, and enjoys writing. He is married to Delma, with four adult children and grand-children.
Mark Tronson's archive of articles can be viewed at http://www.pressserviceinternational.org/mark-tronson.html