A US advisory panel voted yesterday to back the routine use of Merck & Co's human papillomavirus vaccine Gardasil in all females aged 11 to 26 and, in some cases, even as young as nine. HPV is the leading cause of cervical cancer in women, with almost 10,000 new cases diagnosed every year and 3,700 deaths.

The US Centers for Disease Control's advisory committee on immunisation practices has recommended Gardasil be routinely given to girls at the age of 11 or 12, but said the vaccination could be administered as young as nine or between the ages13 to 26 - preferably before they become sexually active, although this is not a prerequisite for immunisation.

News that the CDC has added its weight to a nationwide immunisation programme will be a boon to Merck, which anticipates Gardasil will become a much-needed multi-billion dollar earner for the firm, after the tremors that have followed the withdrawal of its painkiller Vioxx (rofecoxib) in 2004.

Gardasil was given the green light by the US Food and Drug Administration last month, jumping the gun on its rival Cervarix from GlaxoSmithKline, which is not due to be filed until the end of the year. Gardasil is effective against four types of human papillomavirus, including two that cause about 70% of all cases of cervical cancer, the most common sexually transmitted disease in the USA. More than 20 million have the virus already and there are 6.2 million new infections every year, says the CDC, which points out that at least 80% of women will have acquired HPV infection by the age of 50.

The regimen is given over a six-month period in three shots, and has a price tag of $360, which could cause some ripples of discontent. In the meantime, Merck is also hoping to extend the labelling for Gardasil to include boys, to reduce the circulation of HPV in the population and cut the occurrence of genital warts.

o The CDC's ACIP also recommended yesterday that Merck's varicella vaccines, Varivax and Proquad, be given as a second dose to children aged four to six to prevent against chicken pox.