Complacency deadly with chameleon virus

By KATHERINE HOBY

Influenza is one of the banes of winter.

It spreads quickly through households, workplaces, and communities.

Thousands of work hours are lost, and millions of dollars spent trying to combat virulent strains of a nasty illness often dismissed as "just the flu".

Ministry of Health spokesman Dr Lance Jennings warns against complacency about the virus.

Until the end of June the ministry will pay for vaccinations for those over 65 years old, as well as those with chronic medical conditions.

Many workplaces offer free flu jabs, hoping to reduce the number of sick days lost to influenza every winter.

Dr Jennings said the vaccination being offered this year was targeted at three strains of the virus: Moscow A, Sichuan B, and New Caledonia A, and similar strains of the three. The two A strains were targeted last year, and Sichuan B is a newcomer.

He recommended annual jabs because the vaccine was aimed at the strains that were expected to cause illness that year.

There are three families of virus, each containing multiple strains. Both the A and B families have strains that cause illnesses of varying severity, but A is worse than B.

Overseas studies suggest vaccinations cut hospital admissions during the influenza season by half and deaths by two-thirds for people aged 65 or over. In general, the vaccination is 70-90 per cent effective in preventing influenza in healthy adults.



Although the body responds to an infection by developing antibodies, a new family member or a new strain in another family may appear the following year. Antibodies are less effective against this unfamiliar strain.

Every 10 years or so a strain appears that is dramatically different from other members of its family.

When this major change occurs a worldwide epidemic, called a pandemic, almost inevitably follows. Few people have antibodies that are effective against the new virus.

One such virus caused the 1918 flu epidemic that swept the world and left more than 20 million people dead.

Laboratories throughout the country are part of a worldwide network that tests for a new virus during the months when influenza is most prevalent, May to September.

The ministry held a nationwide influenza pandemic emergency exercise last month to test the health sector's ability to respond.

It was aimed at updating New Zealand's Influenza Pandemic Preparedness Plan.

New Zealand is the first country in the world to test pandemic practices.

Dr Jennings said Auckland was overdue for an influenza pandemic. The last one was in 1968, "so one could happen at any time".

More than one million chickens thought to be carrying a flu virus were killed three weeks ago in Hong Kong. The cull was carried out because the bird virus can form a deadly new strain if it comes into contact with human influenza.

Facts about the flu

* More than 48,000 New Zealanders had influenza last year and 379 were admitted to hospital with complications.

* The highest rates of illness were reported in the Eastern Bay of Plenty and Manawatu.

* It takes 10 to 14 days for flu vaccine to give full protection.

* Influenza can be a serious disease, and is easily spread by sneezing and coughing.

* Symptoms include a sudden onset of fever, chills, coughing, body aches and pains, fatigue and headaches.

* Almost 300,000 people were vaccinated last year at a cost of $5,265,000 to the Government.

* Flu makes its victims ill for up to 10 days, a cold for two to four days.

* The viruses in the vaccine are inactivated so that those vaccinated cannot get the flu from the vaccine.

* When flu strikes the lungs, the lining of the respiratory tract is damaged. The tissue become swollen and inflamed

* The amount of antibodies in the body is greatest one or two months after vaccination.

* Anti-viral drugs such as Tamiflu (Roche), and Relenza (GlaxoWellcome) can also be used to prevent and treat influenza A.

* More information can be obtained by phoning 0800 IMMUNE (0800 466-863).

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