KEY POINTS:
New research on the meningococcal vaccine rates its effectiveness at 69 per cent and suggests most children were still protected 12 months after vaccination.
The yet-to-be-published findings by Victoria University statisticians are at odds with follow-up studies for Auckland University's immunisation centre, which found the MenzB vaccine waned below protective levels within months.
The $220 million vaccination campaign began in July 2004 to combat a rampant strain of meningococcal B disease which began in 1991. Public health experts say the Ministry of Health was slow to react and the epidemic was in decline by the time the vaccine was ready - but the experts agree MenzB accelerated the decline and the campaign was worthwhile.
Where they differ is over the emergency vaccine's long-term effectiveness - and whether this matters.
Another follow-up study, by Auckland and Lower Hutt doctors, suggests most vaccinated children are unlikely to have sufficient antibodies to protect against the strain.
But the ministry says antibody levels aren't the only measure and the vaccine is still doing a job. Professor Terry Nolan of Melbourne University, who peer-reviewed the Victoria modelling, says 69 per cent effectiveness is "pretty good" for a one-off vaccine developed for a nasty strain of disease.
But he remains concerned that the ministry suspended vaccinations in April.
"The disease has not been eradicated - it is still circulating," says Professor Nolan.
A long-term vaccine for group B meningococcal strains has yet to be developed, he says.
The controversy has renewed concerns about vaccination safety as the ministry ushers in a new vaccine against human papilloma virus, which can develop into cervical cancer. Gardasil will be available for girls aged 16 to 18 from September 1, despite concerns in the United States about side-effects.
