More than half of the Government's stockpile of the Tamiflu anti-viral medication will be taken up in protecting healthy doctors and nurses if it is used as a preventive treatment for bird flu, says the Director of Public Health, Mark Jacobs.
Use of the drug in healthy people protects them but does not confer immunity to influenza and they are at risk of falling ill once the medication is stopped, he told the health select committee at Parliament yesterday.
The more Tamiflu that was used in such a protective role, the less that would be available to treat sick patients, he said.
Committee chairwoman Sue Kedgley had asked Dr Jacobs whether the legal obligation for the Health Ministry to provide working conditions as safe as practicable would mean it would use the stockpile of Tamiflu to protect doctors and nurses in a bird-flu outbreak.
Ms Kedgley later said outside the committee room that hospital workers had a legal right to refuse to perform duties if they thought their work might cause them harm.
Jackie Blue, a National Party MP on the committee who is also a doctor, suggested to the Director-General of Health, Karen Poutasi, that unless health workers could be assured of protection, some might not turn up for work.
Dr Poutasi disputed Dr Blue's concern that the health system could "fall over" unless health workers were confident they had the best protection available. "We have been through those calculations. We're not going to have enough Tamiflu to give everybody ... to take for three months at a time non-stop."
No country was going to be able to provide that level of protection.
The health ministry has bought 850,000 courses of Tamiflu and has indicated about 10 per cent of it will be reserved to protect people providing essential services.
But MPs were told yesterday that a lot would depend on whether the drug was used to try to ring-fence clusters of infection, to protect people who were not infected, or at a later stage to treat people falling ill.
Dr Jacobs told the parliamentary committee that if the virus mutated to spread easily in humans, only two anti-viral drugs were likely to be useful in New Zealand, Tamiflu and Relenza. He said the Health Ministry had chosen Tamiflu but might yet issue further advice that would result in the purchase of Relenza.
Relenza and Tamiflu are neuraminidase inhibitors, which block the virus from replicating.
If taken within a couple of days of the onset of illness, they might ease the severity of some symptoms and reduce the duration of sickness.
Dr Poutasi said Tamiflu could be used before a person was infected, which could require many doses at regular intervals, or it could be administered in a single course shortly after a person was infected to provide protection.
Across the Tasman, the Australian Government's similar bird flu strategy has been criticised by some experts, who say using most of its stockpile of 4 million courses of anti-viral drugs as preventive medication for essential workers will mean fewer doses will be available to treat people who actually contract the disease.
National MP Tony Ryall on Tuesday disclosed in Parliament the existence of a draft list of people who would be given priority access to the drug.
Health Minister Pete Hodgson told the House that any draft meant little because use of the Tamiflu stocks could not be decided until the way that a pandemic flu was spreading and the groups worst affected were known.
The draft list to receive anti-viral protection in New Zealand included 50 Cabinet ministers and security and intelligence advisers.
Other priorities included up to 60,000 healthcare workers, 8000 police and 9000 military personnel. Another 1500 key infrastructure staff, 1000 border control officials, and 6000 social workers and prison staff were listed.
A pandemic of severe human flu may infect up to 1.6 million New Zealanders and kill up to 33,000 over eight weeks, if it follows a similar pattern to the 1918 epidemic.
Dr Poutasi told the select committee that all the countries with stockpiles were struggling with the best way to use Tamiflu. New Zealand's list of priorities for its use was only in its first draft, and the final analysis might change if there was a chance to see how other countries fared when they used their stockpiles before the pandemic spread in this country.
She said the New Zealand stockpile might be augmented with further anti-viral purchases, if they were available.