Australia's breakthrough cancer vaccine has been given the all-clear in a follow-up study of schoolgirls who fell ill after being injected with Gardasil.
The study took in 25 young women who were reported to immunisation authorities as suffering a "suspected hypersensitivity" reaction during the national roll-out of the cervical cancer vaccine.
After a range of skin prick and injection tests, only one young woman went on to develop a case of possibly unrelated hives when re-exposed to the vaccine.
"Only three of the 25 evaluated schoolgirls had probable hypersensitivity to the quadrivalent human papillomavirus vaccine after 380,000 doses had been administered in schools," the research paper, published in the British Medical Journal, also concludes.
"Our data suggest that true hypersensitivity to the ... vaccine is uncommon and that suspected hypersensitivity reactions such as urticaria (hives) are often idiosyncratic."
The study was conducted by Dr Sharon Choo, attached to the Department of Allergy and Immunology at Melbourne's Royal Childrens Hospital, and fellow colleagues.
Gardasil, developed by former Australian of the Year, scientist Ian Frazer, provides protection against 70 per cent of cervical cancers by blocking two strains of the sexually-transmitted human papilloma virus.
The national vaccination of females aged 12 to 26 got underway in April last year when it also sparked media reports of fainting and dizzy spells, even temporary paralysis among some schoolgirls.
The research paper also notes such reactions were typical during any mass vaccination effort, regardless of what was being injected.
"One study estimated that if 80 per cent of eligible US adolescent females were to receive a saline (sterile saltwater) injection ... three per 100,000 adolescents would require emergency care for asthma or allergy within 24 hours of vaccination."
