Plan aims to delay pandemic

The Government moved yesterday to avoid panic after the World Health Organisation's declaration of a pandemic. Photo / Greg Bowker

Up to half New Zealand's population could catch swine flu over the next two years, public health specialists predict.

They are trying to delay the likely dramatic rise in the number of cases, spread the outbreak's impact over a longer time and avoid it coinciding with the usual winter flu season.

The Government moved yesterday to avoid panic after the World Health Organisation's declaration of a pandemic - a worldwide outbreak - of A H1N1 swine influenza.

"New Zealand is going to carry on the way it has, and we will keep people informed of any changes that need to be made," said Health Minister Tony Ryall.

More than 28,000 cases, including 144 deaths, have been reported around the world. Australia has 1300 cases.

In New Zealand, where the disease has generally been mild, the number of confirmed cases rose yesterday to 34, including seven new ones.

All are people who caught the disease while travelling overseas, which indicates that it is not being spread in New Zealand.

Based on World Health Organisation calculations, the New Zealand public health experts predict about half the population - more than two million people - could become infected during the outbreak here.

But the estimates vary greatly, from 20 per cent to 60 per cent.

The experts cannot predict whether there will be a huge number of cases in New Zealand over a period of weeks - as happened during the second, killer wave of the 1918 flu pandemic - or if the outbreak will spread over a longer period, affecting fewer people at any one time.

They hope for a longer spread, even if the same number of people ultimately contract the disease, because this would reduce the effect on schools, businesses and health services.

The deputy director of public health, Dr Darren Hunt, said this was why the Ministry of Health and regional public health units were putting so much effort into identifying infected people as they arrived from overseas and tracing those with whom they came into contact.

"If we could flatten the normal, bell-shaped epidemic curve, that would be good in terms of the impact," he said.

Once swine flu starts spreading rapidly, health authorities will move from the present "containment" phase, to "mitigation".

They will stop aggressively tracing contacts, and less use will probably be made of the Government's stock of more than 1.2 million courses of anti-flu drugs.

Yesterday's new cases include two sisters, aged 10 and 13, who were admitted to the Starship children's hospital in Auckland on Wednesday night because they have asthma, which the disease can trigger.

They are being treated in an isolation area.

Their parents are both well. The mother has been offered the flu drug Tamiflu as a precaution and is in isolation on her daughters' ward. The father is in quarantine at home.

The hospital says staff who came into contact with the girls have been given Tamiflu as a preventive and are continuing to work, using protective equipment.

Auckland City Hospital's renal ward remains in isolation after a nurse and her son tested positive for swine flu. Three patients developed fevers, but it was not known yesterday if this was caused by swine flu.

New Zealand and overseas experts are trying to predict the course of this pandemic by studying the three influenza pandemics last century.

The worst was the 1918 Spanish flu, which is thought have killed more than 50 million. It affected New Zealand in a mild wave in September-October, then in a much more virulent second form for six weeks from late October.

The "Asian flu" of 1957 and 1959 caused infection rates of 20 to 70 per cent worldwide, but the fatality rate was low.

"Hong Kong flu" affected New Zealand in 1969 and was of similar severity to the Asian strain.

The Labour Department is urging employees and employers to agree in advance "how they will manage the employment relationship during the outbreak".

Workers do not legally have to be paid if they have to stay home to look after a child unable to attend school because of a pandemic-related closure, although employment agreements could cover this.

A senior lawyer at law firm Buddle Findlay, Iris Reuvecamp, said an epidemic notice - which can be issued only by the Prime Minister - could allow temporary changes to laws covering, for instance, employment and contracts.

School Trustees Association general manager Ray Newport said it was possible state school teachers prevented from working by the pandemic could be paid sick leave without having the days deducted from their sick leave entitlement, but this would depend on the Education and Health Ministries.

Swiss pharmaceuticals company Novartis AG said yesterday that it had produced a first batch of experimental swine flu vaccine.