No link between Gardasil and infertility: TGA
The medicines watchdog has found no evidence to link the genital warts vaccine, which has been credited with a dramatic reduction in the occurrence of the illness, to premature ovarian failure and infertility.
In answer to a question on notice, Health Minister Tanya Plibersek said the Therapeutic Goods Administration found that there was no “plausibly biological basis” for drawing a link between the vaccine Gardasil and premature ovarian failure.
The issue arose following a report in the British Medical Journal late last year of the case of a 16-year-old Australian girl who suffered premature ovarian failure after being vaccinated against the human papillomavirus (HPV).
According to the lead author of the report, Dr Deirdre Little, the girl’s menstrual cycle became scant and irregular following vaccination. She declined to take oral contraceptives, as initially prescribed for amenorrhoea, and suffered premature ovarian failure.
“Although the cause is unknown in 90 per cent of cases, the remaining chief identifiable causes of this condition were excluded,” Dr Little said in her report. “Premature ovarian failure was then notified as a possible adverse event following this vaccination.”
But in her written answer to a question from West Australian Liberal Senator Michaelia Cash, Ms Plibersek said the medicines watchdog had not found evidence of a link between Gardasil and premature ovarian failure, and did not think there were grounds to undertake long-term surveillance of ovarian function among immunised girls and women.
“The TGA has not identified a possible safety signal for premature ovarian failure following Gardasil vaccination,” the Minister wrote. “In addition, the TGA does not consider that a plausible biological basis for a causal relationship between the administration of Gardasil vaccine and the occurrence of premature ovarian failure has been established.”
In her answer, Ms Plibersek said oligomenorrhoea and amenorrhoea were “common occurrences” in teenaged girls and young women, and could have many possible causes.
Out of 6.7 million doses of Gardasil distributed in Australia between 2006 and the end of last year, the case reported by Dr Little was the only incident the TGA had been informed of involving a possible link between the vaccine and premature ovarian failure.
“The TGA considers there is insufficient evidence of a safety signal with Gardasil to warrant undertaking a specific long-term follow up of ovarian function in a cohort of vaccinated girls and women,” the Minister wrote.
In all, the TGA reported it had been advised of 1983 suspected adverse events following vaccination with Gardasil, including 1585 where Gardasil was the sole vaccine administered.
The regulator found that the majority of adverse reactions were mild and well recognised: almost one in five involved headaches, 18.4 per cent involved reactions at the site of the injection, including bruising, pain, swelling or a rash, 15 per cent were for nausea, 14 per cent dizziness, 11 per cent for fatigue and lethargy, and 10.6 per cent involved fever.
There were 167 cases (9.1 per cent) where the recipient fainted, and 19 reported instances of anaphylactic reaction.
The TGA reported that there was no evidence that the incidence of demyelinating disorders such as multiple sclerosis was any higher following Gardasil vaccination than would occur by chance.
The low incidence of reported adverse events following Gardasil vaccination (less than 0.03 per cent) has come amid hopes genital warts could soon be eliminated because of the treatment.
As reported in the last edition of Australian Medicine (see https://ama.com.au/ausmed/war-warts-being-won), the incidence of genital wart cases among young women has plunged since the nationwide human papillomavirus vaccination program began in 2007.
A study in the BMJ found rates of diagnosis among women 21 years or younger has plummeted from 11.5 per cent in 2007 to just 0.85 per cent in 2011, a fall of almost 93 per cent.
Hopes to eliminate the disease, which can cause cervical cancer, have been boosted by the Government’s decision last year to extend the vaccination program to include boys.
Internationally, the GAVI Alliance – a global joint public and private partnership partially funded by the Australian Government – has announced plans to vaccinate 30 million girls in 40 of the world’s poorest countries against HPV after negotiating a deal with manufacturers for supplies at just $4.40 a dose, a big discount on its cost in developed countries.
Published: 17 May 2013