Two-dose HPV vaccine looks likely

Doctor making insulin or flu vaccination shot by syringe to a young woman

Evidence is growing in support of a two- instead of three-dose HPV vaccination regimen in Australia

This evidence is currently being reviewed by the Australian Technical Advisory Group on Immunisation according to Associate Professor Julia Brotherton, who is medical director of the National HPV Vaccination Program Register.

Around 65% of countries are already shifting their HPV vaccine schedule from three- to two-dose regimens based on the evidence, A/Prof Brotherton told MJA InSight this week.

For example, new research published in the Journal of Infectious Diseases this month found a two-dose regimen of the HPV 16/18 AS04-adjuvanted (bivalent) vaccine in girls aged 9-14 years was non-inferior to a three-dose regimen in women aged 15-25 years.

“It certainly seems to produce adequate antibody level [when] it’s targeted at pre-adolescents who have a more robust immune response [than older women],” A/Prof Brotherton said.

She predicts Australia will move to a two-dose schedule some time in the future although probably not for the 2017 school year.

Professor Karen Canfell, Chair of Cancer Council Australia’s Cancer Screening and Immunisation Committee, said that a two-dose regimen could improve coverage rates.

“Reduced dose schedules are seen as very important to the practicality of vaccine delivery globally and I think even in Australia we could potentially see a benefit via the higher coverage rates that might be achievable, pending an assessment of the safety and efficacy of two-dose regimens by the PBAC,” she said.

However, she says questions remain about the long-term efficacy of a two-dose vaccine.

“It’s certainly looking very promising that we can expect life-long protection from the three-dose schedule.

“There is just a question mark on the two-dose schedule as to whether it’s going to be adequate in the long-term, so that’s the calculated risk that you’re taking [in shifting to a reduced schedule].”

There is also growing evidence for the next generation nonavalent vaccine Gardasil 9, which was approved by the TGA last year and is expected to be considered by the PBAC for inclusion in the National Immunisation Program.

Prof Canfell said this next generation vaccine has the potential to boost protection against cervical cancer in fully vaccinated females from 70-75% with the current generation, to 90%.

“If we are going to make a change to the [nonavalent] vaccine and a change to the [two-dose] schedule, it would be much better if we did it all in one go,” she said.

Read the full MJA Insight article here.

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