How do vaccines affect immunity?

Vaccines train your baby’s immune system to quickly recognise and clear out germs (bacteria and viruses) than can cause serious illness. Vaccines will strengthen your baby’s immune system a bit like exercise strengthens muscles.

Can vaccines overwhelm a baby’s immune system?

Vaccines can’t overwhelm a baby’s immune system because their immune system is equipped to protect them from thousands of germs every day. From the moment they are born, babies are exposed to countless germs (bacteria and viruses) through their skin, noses, throats and guts. Babies’ immune systems are designed to deal with this constant exposure to new things, learning to recognise and respond to things that are harmful.  

Vaccination does not interfere with the ability of your baby’s immune system to respond to other germs. Even if all the doses on the immunisation schedule were given to a baby at the same time, only a small fraction of available immune cells would be occupied.

Would it be safer to vaccinate babies when they’re older?

Vaccinating babies when they are older leaves them without protection against diseases that can be serious. This means they aren’t protected at an age when those diseases are most common or most serious.

Babies and young children are most vulnerable to infections when they are very young. Vaccinating them before they come into contact with serious infectious diseases gives babies the best possible protection.

Would it be better for children to develop their own immunity?

Allowing children to develop immunity by catching infectious diseases is not safe. Catching a vaccine-preventable disease can protect a child from catching it again, but it can also make them seriously ill in the process. Occasionally children in Australia still die as a result of catching a vaccine-preventable disease.

Vaccination is recommended because it is the safest way to develop immunity. Vaccines are designed to stimulate immunity without causing disease. The side effects of vaccination are usually mild (like getting a sore arm) and pass quickly but the diseases they prevent can cause serious illness requiring hospital treatment.

Are the diseases still around anyway?

Some of the diseases children are vaccinated against, like whooping cough and flu, are still common among children living in Australia. In 2017 four people caught tetanus. One was a boy under four years old and one was a girl between 5 and 9 years old 1.

Others, like measles are less common in Australia but are more common in nearby countries in the Pacific and South East Asia. Vaccinating your child will protect them from diseases which could be brought into Australia by travellers, or which they might catch if they travel overseas with you.

Some of the diseases we vaccinate children against, like polio, have become very rare in Australia because vaccination has stopped them from spreading. We still vaccinate Australian children against these diseases to stop them from coming back.

  1.  National Notifiable Disease Notification Surveillance System