Thursday, 30 April 2009

Basic Facts About Flu, Vaccines And Anti-Virals

This post is just to clear up some ideas I have heard people voice about flu, vaccines against flu and anti-viral medication.

Flu, (influenza) is a viral infection. The only way a virus will be killed is when the immune system develops antibodies to neutralize the virus. This means that it is pointless to take antibiotics, since they only kill bacteria, not viruses. Bacteria tend not to invade cells, they live in between the cells. Viruses are much smaller than bacteria and are able to cross into the cell and take over the reproduction of the cell. In order to kill a virus, either the immune system has to develop antibodies to that virus or you need a drug that halts the reproduction of the virus (which means it has to be able to get inside the cell to deal with the virus). Each virus has a different 'template' which means that only an antibody that contains the 'reverse' of that template can neutralize the virus.

People believe that antibiotics will kill flu virus - they will not. Viruses are not killed by antibiotics. There is a case for giving antibiotics to flu sufferers who are also at risk of a 'secondary' (opportunist) bacterial infection. These are generally people whose immune system is not working properly (HIV/Aids) or people without spleens, people with diabetes, asthma, COPD or other chronic diseases. Apart from these people, antibiotics play no role in the prevention or treatment of flu.

People believe that flu vaccines will stop them getting flu. This is not true. The WHO meet every year to decide which four viruses are most likely to be present in the flu season that particular winter. Some years they get it spectacularly wrong and none of the four types of viruses they thought might cause flu that year are actually present. Meaning that drug companies have produced a vaccine on the basis of an erroneous forecast and people will contract flu despite having had their flu shots that year. In fact there may be some evidence (though not thoroughly tested) that flu vaccines actually impair the ability of the body to deal with flu and can cause the onset of some auto-immune diseases. Flu vaccines can be accidentally contaminated with other substances (see my previous post re Baxter's) and my personal opinion is that I will never ever have another flu vaccine again, nor would I advise anyone I love or any of my patients to ever have a flu vaccine either.

Anti-viral medication. Apparently there are some drugs available that are able to help when you have contracted flu. Please note, these drugs are not preventive measures, they are to be taken at the onset of flu type symptoms. Since flu type symptoms in their early stages resemble the onset of a common cold (though tend to be faster in onset than a normal cold) I am not sure when I would advise anyone to start taking 'anti-viral flu medication'. These drugs are supposed to stop the virus from reproducing, but they will not prevent you from catching the virus in the first place, and they are therefore not a preventative measure.

The best way to prevent flu is to not be in contact with a person who has been infected. Since the incubation period (the time between being infected with a virus and the onset of symptoms) can be as long as 10 days, this is almost impossible to achieve. The most common way a flu virus spreads is by 'droplet' infection. The person affected sneezes and the virus is sneezed into the air. Unfortunately because of the way we have been brought up, we normally bring our hand to our nose when we sneeze, which means that the MOST common way to contract the virus is by hand to hand or hand to object contact. An infected person sneezes (and the virus ends up on their hands). Any contact with an object handled by that person, or contact with the hand of that person, can result in the person who has that contact, also picking up the virus.

The best way to prevent flu is :-
1. Avoid people with symptoms of colds and flu type symptoms
2. If you have to have contact with them, make sure you scrupulously wash your hands every time you have touched an object touched by the affected person.
3. Make sure they do not sneeze over you or any other objects which you then touch.
4. Keep your hands away from your face.
5. Masks used to cover mouth/nose only last about 15 mins. Once they are 'wet' by breath/saliva touching them, they are useless.

At the moment we do not know exactly how long the virus will survive on 'objects' since this varies with factors such as the fabric of the object and the ambient temperature.

A proper vaccine against the current outbreak of 'swine fever' will take at least three months to develop, and the production of any significant number of these vaccines will take longer.

I hope this post clears up some misconceptions people have about the nature of viruses, flu, bacteria and what we can do about them, and if it even prevents one person from contracting the flu, it will have done its job.

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