August 01, 2010

Article at Cosmos Magazine

OPINION | Jumping at Shadows

Immunisation rates in parts of Australia are falling - in some places, below 75%, which means the herd immunity on which we all rely is gone.

By Wilson da Silva

I RECENTLY BECAME an uncle for the first time, and delighted in holding my newborn nephew in my arms. It’s a joy that parents and relatives – and uncles – experience around the world every day, and have done for millennia.

It can be scary, too. Newborns have many needs, such as round-the-clock feeding, sporadic sleep patterns, colds, coughs, fevers and vomiting. They also have health issues that differ from adults, such as cradle cap, a form of dermatitis that affects babies in their first few months and causes greasy, yellow crusts on the scalp.

But this is a far cry from the fears of parents through history. The 20th century saw the introduction of many successful vaccines against diseases that once devastated whole communities: diphtheria, measles, pertussis, mumps and rubella to name a few. Vaccines have been so successful that, in developed nations such as Australia, we have the luxury of consigning them mostly to medical textbooks.

That’s not the case everywhere: a recent outbreak of measles in eastern and southern African nations struck 48,000 children and killed 731 people. Spread via contact and respiration, it is highly contagious: 90% of people without immunity who share a house with an infected person will catch it.

Average incubation is 14 days, with a victim being infectious for up to four days before the appearance of a rash, and five days afterward. Victims experience high fever (over 40°C), itchiness and a rash, with complications being common, ranging from diarrhoea, pneumonia, encephalitis and corneal ulceration leading to scarring.

In underdeveloped nations with high rates of malnutrition and poor healthcare, fatality rates can reach 28%, numbers we would only see in Australia among immuno-compromised patients, such as those with AIDS or certain forms of cancer. For otherwise healthy people in wealthy nations, the rate of fatality is three deaths per thousand cases, or 0.3%.

Arnold Barnett, a mathematician at the Massachusetts Institute of Technology in Boston who specialises in the statistical analysis of aviation, calculated that the risk of dying in an airline accident in rich nations is about one in 13 million (or a global average of one in two million): to die, you have to fly once a day for 36,000 years.

He also analysed how the media reports fatalities. The New York Times, for instance, reported two cancer stories for every 100,000 cancer deaths, 1.7 murder stories per 1,000 homicides and 138.2 plane crash stories per 1,000 aircraft deaths. Is it any wonder people are more worried about being murdered or dying in a plane crash?

And is it any wonder so many parents are confused about vaccination, when 43% of Google results to a search for ‘vaccination’ and ‘immunisation’ delivers sites that campaign against immunisation or portray vaccination as dangerous, as a University of Sydney study has found?

The truth is even scarier. Immunisation rates in parts of Australia are falling; in some places, they’re below 75%, which means the herd immunity on which we all rely is gone. As one clinical practitioner told me, it only takes one case of pertussis (or whooping cough) and the disease rages through these communities.

It’s a serious ailment, triggering coughing fits for two to eight weeks; complications include pneumonia, encephalopathy or seizures, which in newborns is particularly severe. Last year, an epidemic of whooping cough in Australia saw a threefold increase in cases – about 30,000 – and resulted in the deaths of at least three children.

How many unvaccinated uncles – or friends, parents, and grandparents – have held newborns in their arms, not realising the potential danger they posed to the infant, who is most vulnerable in the first six weeks of its life?

Yes, immunisation can have side effects: redness and swelling at the site of an injection or a mild fever. Severe reactions extremely rare: less than one in 100,000 doses.

Millions of Australians travel overseas every year – many visiting underdeveloped regions. Are the odds not high for an unvaccinated friend or family member to be a carrier?

Medical science has given us the weapons to protect our children: it seems to me irresponsible not to use them.