West Coast DHB on Immunisation

West Coast DHB on Immunisation

There are various reasons why parents do not have their children immunised. Unfortunately, recent outbreaks of diseases like whooping cough and measles are testimony to what happens when not enough members of a community are immunised against them, writes West Coast Medical Officer of Health Dr Cheryl Brunton.

Childhood immunisation provides protection from a range of serious illnesses, including measles, mumps, rubella, polio, diphtheria and whooping cough (also known as pertussis), all of which can have serious complications and may cause long-term harm.

Immunisation not only provides individual protection against these diseases. If sufficient people are immunised, the spread of disease in the community can be slowed or even prevented completely. This population-wide protection, also known as herd immunity, is possible only with high immunisation rates. Regular outbreaks of diseases such as measles and whooping cough occur when immunisation rates are low.

Increased childhood immunisation coverage in New Zealand has been a national health target since August 2007 when only 67 percent of two-year-olds were fully immunised. Nationally, rates for two-year-olds have risen since then to 90 percent in July 2011. The target is 95 percent by July 2012 – a level where communities are likely to be protected from outbreaks of diseases like measles and whooping cough.

The immunisation rate for West Coast for two year olds in June 2011 was 84%, much better than in the past but still a way off the national target for 2012.

This less than ideal rate of immunisation can contribute to outbreaks of disease such as the current whooping cough outbreak on the Coast. Low levels of pertussis infection are present in the community most of the time but with some people choosing not to immunise, and the fact that no immunisation is 100 percent effective, there is always the opportunity for an outbreak particularly when immunisation coverage is not high enough to create herd immunity.

Also, immunity to whooping cough wanes with age so older previously immunised people can contract it. This might not be so serious for them, but it does mean they could infect an unimmunised child.

Why don’t parents immunise?

Why, then, is there so much concern about immunisation? Why do people not immunise their children?

Vaccines do carry some risk, but in healthy children, that risk is very small. As an example, a fairly common reaction to the whooping cough vaccine is pain or redness at the injection site and occasionally, fever. Very rarely (less than one in a million) a child might experience a severe allergic reaction and this is a reason vaccines are always administered by trained vaccinators. The idea that routine childhood immunisations cause autism is also a persistent one, although the research that initially suggested a link has since been comprehensively discredited.

More often the reasons children don’t get immunised are quite simple, such as the thought of sitting in a waiting room with a lot of sick people, distance from the local health centre or simple needle phobia. One of the ways the West Coast District Health Board is working to combat these is through its Outreach Immunisation Programme. Outreach Immunisation Co-ordinator Betty Gilsenan and her assistant travel many hundreds of miles every year to homes on the Coast where there have been problems for families getting their children immunised.

These families will be referred back to a primary care practice for the next round of shots, but if recalls are not responded to, Betty will be back on the road taking the service to their homes.

Getting these hard-to-reach children immunised by making it more accessible can make a big percentage difference to the level of immunisation in a small community.

In New Zealand the national childhood immunisation schedule immunisations are given at six weeks, three months, five months, four years and 11 years. It’s important that immunisations are given on time, particularly for a disease like whooping cough where infants under one year old are most at risk of serious disease.

The potential gains of immunisation are not limited to infants and young children. Some immunisations such as that for influenza, and booster shots for tetanus, are available for older children and adults.

Reaching the childhood immunisation target and getting adults to immunise against other diseases has wide public health benefits. It’s about building a wall of protection against avoidable diseases and staying healthy.

ENDS

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