While measles can be a dangerous illness with long-term side effects for any child, it has a more than 50% death rate for New Zealand children with low immunity.
As well as causing death, measles can cause pneumonia, deafness and brain damage.
In this country, the biggest group of children with low immunity are those receiving cancer treatment. Chemotherapy attacks bone marrow and reduces the effectiveness of the immune system, making people much more susceptible to infection, particularly from viruses such as chickenpox and measles. While there is now treatment available for chickenpox, there is no effective treatment for measles.
These children cannot be immunised
Because the measles vaccine contains a live virus, vulnerable children cannot be immunised but everyone around them needs to be.
Previous immunisations or exposure to illnesses will only partially protect children who have had chemotherapy because the damage done to their immune system erases much or all of the body’s memory that it has seen the virus before.
A child’s immunity continues to drop as they receive more chemotherapy. For patients with leukaemia – the most common type of childhood cancer – their immunity continues to decline over the 2–3 years’ worth of treatment. It also remains severely impaired until at least 6 months after treatment has ended.
When children have finished receiving their cancer treatment they are re-immunised, with the measles vaccine the first to be given during a measles outbreak.
What can we do to protect them?
The most important thing we can do to protect children with low immunity is to make sure that we and our children are immunised against measles, so that we cannot spread the illness.
It is especially important that extended family members of a vulnerable child, their friends and anyone who comes into contact with them are immunised against measles or they should keep away from them. If they have not been immunised, this should be done as soon as possible.
People can worry that they will give a vulnerable child measles from being vaccinated with the Measles, Mumps and Rubella vaccine because it is a live virus vaccine, but this is not a risk.
What do vulnerable children need to do to protect themselves?
If there are measles cases at the child’s school, they need to stay away from school until the risk of getting measles has passed. Information about when it is safe to return to school is given by the local Medical Officer of Health.
Children with low immunity also need to stay away from crowds of people, particularly during a measles outbreak. This means keeping away from places such as shopping malls, movie theatres and big events or going at off-peak times.
Regularly using hand sanitiser is important for affected children and those caring for them. Special precautions also need to be taken in hospitals during a measles outbreak to keep measles patients away from others.