As governments around the world continue to roll out free or subsidised vaccinations against the human papillomavirus (HPV) for young girls, the medical world is starting to ask overdue questions about its safety and effectiveness against cervical cancer. An editorial in The New England Journal of Medicine says many questions about the two vaccines on the market remain unanswered so “there is good reason to be cautious”. Norwegian Dr Charlotte Haug points out that the vaccines, Gardasil and Cervarix, have been studied in clinical trials for at most six and a half years -- a relatively short time. No-one knows how long the immunity will last, or whether eliminating some strains of HPV will decrease the body’s natural immunity to other strains. The theory that the vaccines will reduce the incidence of cervical cancer remains to be proven.

A second article in the NEJM by Dr Jane J Kim and Dr Sue Goldie of Harvard expresses doubts about the cost-effectiveness of the vaccines. Already the US government faces a bill of more than $1 billion for making Gardasil available to the poorest girls in the country up to the age of 18. The authors say such expenditure will be worthwhile only if they prove to protect girls for a lifetime, and if current methods of screening for cervical cancer (Pap smears) begin to cost less.

A New York Times article investigating the HPV vaccines notes that some experts question the pressure tactics that have been used to promote the vaccination of all pre-adolescent girls. “[E]ven parents of girls who are far from being sexually active may feel pressured into giving them a vaccine that is not yet needed and whose long-term impact is till unclear,” says the Times. ~ NYT, August 21