Vaccines cause herd immunity

The World Health Organization (WHO) estimates that immunisation averts 2-3 million deaths worldwide each year.^[1] Vaccines don’t just save the lives of the children vaccinated. They save the lives of those who are not vaccinated by ensuring pathogens cannot spread quickly across the population. This is called herd immunity.^[2] Immunisation aims to protect the individual against a disease. It also makes that person less likely to be a source of infection to others so protecting those that are not immunised as it stops the germs responsible for infections being transmitted between people. A significant number of the population need to be immunised to offer herd immunity – this number depends upon how infectious the disease is. Children with weakened immune systems due other diseases or medications they are taking are not recommended to be immunised. These included lung, heart, liver, kidney disease or diabetes. Newborn babies are deemed too young to be immunised. Children receiving chemotherapy for cancer are not offered immunisations due to their weakened immune system. Measles has a 50% death rate for children with a weakened immune system so the importance of herd immunity can be seen here to protect vulnerable children who are unable to be immunised.

[P1] Vaccines save lives not only by protecting those who are immunised, but those who haven't or can't be immunised.