A dramatic drop in genital warts is evidence the $10 million approximate annual cost of the human papillomavirus (HPV) vaccine is justified, the co-author of a new study says.
Prof Tony Blakely, of the University of Otago's Wellington campus, said this was despite coverage of 47% in the period reviewed.
It had since risen to more than 55%, but was still significantly lower than in Australia and the United Kingdom.
''Incidence of warts has fallen quite dramatically, which is good news,'' Prof Blakely said.
The study recommends New Zealand consider following Australia and not offer a GP-delivered vaccine as an alternative to the school-based option.
''Having the option to either have the vaccination at school or to delay a few years and get it from the GP is likely causing a lot of parents to delay.
''One possible way to achieve higher coverage might therefore be to have only a free school-based programme, as in Australia, with the requirement to pay the full market price in other settings.''
Introduced in 2008, the vaccine has been offered to girls through schools in year 8, or through primary care (aged 12 to 20) since 2011.
Surveillance clinics around the country reported a declining number of first presentations for genital warts and the steepest reductions were occurring in women aged 15 to 19.
Pharmaceutical data for genital warts treatment also showed a downward trend. Prof Blakely said the three-shot programme cost more than $750 per person, of which more than $330 was for the vaccine.
It was an expensive programme, and there was scope to reduce costs, he believed.
Signals from the World Health Organisation suggested the third shot might be unnecessary, and it might be dropped in future.
If this occurred, it would further increase the programme's cost-effectiveness.
Warts were an early indicator for cervical cancer reduction, which would take more time to gauge. More could be done to push the benefits of the vaccine's potential to reduce cancer, he said.
''Our view is that greater emphasis could be given to [explaining] that it will protect against multiple other cancers that affect both men and women, and that it is best given well before the typical age of sexual debut, to maximise its benefit.''
Prof Blakely recommended health authorities consider giving the vaccine at the same time as other vaccines given to the same age group, to reduce cost.
