Vaccination

Vaccination is a way of protecting the body from future infections.

How vaccination works

 * When a new pathogen infects the body, the white blood cells need to learn how to kill it; this is a process which takes some time to occur. By the time the white blood cells can deal with the pathogen, it will already have made the person rather ill. This is why vaccination comes in handy.

Vaccines contain small amounts of weakened or dead microorganisms. These have antigens, which trigger production of antibodies to attack them, although the microorganism cannot cause any harm as it's either dead or weakened.

Memory cells which recognise the microorganism's antigens will be produced. If the body is infected with the same microorganism after the vaccination, the memory cells will create antibodies quickly to attack and kill the microorganism before it causes any damage.

Some vaccinations can lose their effect over time. In these cases, booster vaccinations might be given to bring the levels of antibodies in the blood back up.

Advantages of vaccination

 * Vaccinations have controlled many infectious diseases which were much more common in the past. Examples of these include measles, mumps, rubella, whooping cough, tetanus and polio. Vaccination can even eradicate diseases too; smallpox has been eradicated completely, and polio is currently on the brink of eradication.
 * If a large percentage of the population is vaccinated against a disease, epidemics (large outbreaks of diseases) can be prevented. Even those who aren't vaccinated will have a low chance of contracting the disease as there won't be many infected people who can spread it. Sometimes this is referred to as herd immunity. However, if a large number of people aren't vaccinated, the disease can pass from person to person quickly, and lots of people will be infected at once as a result.

Disadvantages of vaccination

 * Vaccines don't work every time they are given. Some people may not develop immunity from the vaccination.
 * Vaccines can cause unwanted side effects, such as swelling, fever or even seizures. Fortunately, serious side effects are uncommon. Additionally, some individuals have weakened immune systems, such as those suffering from HIV/AIDS. In such situations, doctors will need to be vigilant in deciding whether or not these people should receive vaccines.

MMR vaccine controversy
The MMR vaccine is a vaccine that protects against measles, mumps and rubella. In recent years, it has become controversial as one study suggested a link between the MMR vaccine and autism. After news of this study surfaced, it became advisable to give separate vaccines for measles, mumps and rubella as an alternative to the combined MMR vaccine. Less parents decided to give their children the MMR vaccine as a result.

However, more recent studies have shown no correlation between the vaccine and autism, but some people still do not trust the MMR vaccine.