Everything You Ever Wanted to Know About the Flu Vaccine But Were Afraid To Ask

It’s flu vaccine season again. Hurrah! Here is my guide to what exactly the flu vaccine is, and who should and shouldn’t get it. It’s a bit of a long post – there’s lots to say – but hopefully people can scan to the bit you’re interested in.

What is Flu?

Flu is short for influenza. Influenza is a very specific virus that causes an illness typically consisting of high fever, sore throat, dry cough, severe fatigue and muscle aches. In normal circumstances the illness goes on for between 3 and 7 days then you get better, but it can be much more severe and accounts for an average of about 36,000 deaths per year in the USA. It is spread through sneezes and coughs and is extremely infectious. One of the difficulties I have explaining flu and the vaccine is that “flu” is one of those words that means different things to different people. It is common to say “I’ve got flu” to describe respiratory illnesses with varying severities and caused by many many different viruses. To the medical world, however, “flu” is short for “influenza” and means the illness caused only by the influenza virus and none of the myriad other little viruses that can cause colds (which can still make you feel pretty lousy).

Although there are drugs marketed that fight flu once the illness has started, there is a great deal of controversy in the medical world about exactly how much good these drugs do. Basically, there is very little that can be done about it once it kicks in other than supportive measures ranging from paracetamol (which keeps your temperature down and makes you feel a bit better) to giving oxygen if it affects the lungs badly or antibiotics if you get a superimposed bacterial infection. Once you have contact with the virus, the immune system has to fight it off, so we really need to avoid contact with it, or ready the immune system for its presence. All we have to prevent it is hand washing, hoping sneezers and coughers cover their faces when they spray viruses out on the train, and having a vaccine to try to build an immune respose prior to contact with the virus.

What is the Flu Vaccine?

The flu vaccine is an inactivated vaccine that causes the body to make antibodies to 3 strains of the influenza virus, but not to any of the other types of viruses that can cause colds. (There is a new, nasal-spray live vaccine also, but it’s not available in Australia yet as far as I know.) To complicate matters more there are lots and lots of different strains of influenza. Each year, just before the northern hemisphere summer, a group of very clever virologists and epidemiologists meet (in a manner that I always imagine to be similar to the Jedi Council meeting, but is probably less impressive in reality) and decide which strains of influenza are likely to be the 3 most troublesome in the forthcoming flu season. (They do this by looking at data from labs across the world to see which strains are coming and going.) The 3 strains most likely to cause severe and common illness are picked to go into that year’s vaccine. All the influenza vaccines commonly available in Australia at the moment are so-called ‘trivalent’, that is they protect against 3 strains of influenza.

Being an inactivated vaccine, there are few adverse effects from it. It does, of course, aim to provoke an immune response, which itself can make a person feel a bit under the weather, and it can certainly cause a sore arm for a couple of days. Only protecting against 3 strains of influenza means that if you are unlucky enough to have contact with one of the other strains you can still get the flu, and of course, sitting in a doctor’s waiting room for 20 minutes waitng to have a jab is the ideal environment to catch a cold. However, the flu vaccine does not cause flu. There has been (especially in the Northern Hemisphere) a rare adverse effect where the vaccine has triggered a neuro-muscular condition called Guillain Barré Syndrome. The incidence of this is between 1 and 2 per million vaccinations given.

Because the dominant strains of influenza change each year, and because the immune response triggered by the inactivated vaccine is not particularly strong, the vaccine is not 100% effective (its effectiveness ranges from about 60 to 90%), and it is necessary to get a booster vaccine each year. Children under the age of 10 need 2 doses the first year they have it, and then just 1 per year after that.

Who Can’t Have the Vaccine?

I’ve done this list first, cos it’s short. Ready?
People under 6 months old.
People who have had an anaphylactic (severe allergic) reaction to flu vaccine or any other vaccine previously.
People who have an anaphylactic reaction to egg.
People who have previously had Guillain Barré Syndrome that happened just after having the flu vaccine.

Who should get the vaccine?

People over 65. Although normally unpleasant, flu is not normally dangerous. However some groups of people are more likely that others to have a severe attack. At worst, flu can kill. The older you are, the more likely it is that you will get flu badly, so the government offers free flu vaccines for everyone over 65.

Pregnant women. Pregnancy changes your immune system (so it doesn’t attack the developing baby), and with that some illnesses are more likely to be severe. One of these is flu. For that reason all pregnant women, at any stage of pregnancy, are advised to have a flu vaccine for which the government will pay. Having a flu vaccine creates antibodies that not only protect the mother, but also travel across the placenta and confer some protection against flu to the baby in his or her first few months of life. Being vaccinated also means that the mother is less likely to carry the virus and thus spread it to the baby.

The other groups of people who are more likely to get flu badly, and are thus entitled to a free vaccine are: all Aboriginal and Torres Srait Islander poepler age 15 and over; all nursing home and residential home residents and anyone over 6 months old who has a chronic health condition that necessitates regular medical review or hospitalisation. This includes people with cardiac disease, bad respiratory disease, impaired immunity, diabetes and chronic neuromuscular conditions.

Healthcare workers. Although hopefully fit and well, healthcare workers (and this includes all the medical students reading this) are in constant contact with lots of people who, were they to get flu, could get really unwell. For that reason, I advise all healthcare workers to have the vaccine so they minimise the chance they could spread the illness to someone who gets very unwell from it.

Parents and carers of little babies. There is lots of talk about parents and carers of little babies ensuring their whooping cough vaccinations are up to date. This is becaause whooping cough is an illness that, although normally not too severe in adults, can be extremely severe in babies. Flu is the same. An influenza infection in a baby will commonly result in hospitalisation and can be fatal. Babies under 6 months old cannot be vaccinated, but if we can minimise their exposure to flu by vaccinating their carers, perhaps we can reduce the chance of them getting the illness.

Travellers. Airports are great places for spreading flu, as are any crowded area with lots of people close together. Influenza is a common overseas-caught infection, so before getting on a plane it’s worth making sure you’ve done everything you can to avoid catching something that could really spoil your trip.

Everyone else. You have to be unlucky to get the flu, but if you get it it really ruins a week, and it can spread around families and make for a shocking few weeks of fevers coughs and sore throats. A flu vaccine is the best protection we have against this happening. It’s not 100% protection by any means, but it helps enormously, and the $20 price tag and sore arm is a whole lot better than the illness.

What about Kids? OK, I relent. Having a needle each year (with, in the case of the under 10s, 2 in the first year it’s given) understandably puts lots of people off having the vaccine and is a big reason children often don’t get immunised. However, flu can be severe, and children, with their close up play and notputtingtheirhandsinfrontoftheirmouthswhentheycough are really good at spreading the infection around. It is, of course, up to parents to decide whether or not to get their kids immunised, but my advice is to vaccinate, then go and get an ice cream.

And that is my flu vaccine advice. If people have general questions about it please feel free to ask (the best place would be in comments on the link to this post on my FB page), and if you have specific questions about you or your family (and you are a patient of mine) please feel free to call or make and appointment to discuss things further.

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