BANGALORE: An advertising blitz launched by a multinational drug firm to promote its high profile but controversial cancer vaccine has left Indian households confused and health workers worried.

The 15-second commercials seen recently on Indian television urge parents to get their young girls inoculated with the vaccine Gardasil to protect against cervical cancer, the second commonest major cancer in women.

What the ad hides, of course, is that the vaccine is mired in a controversy in the United States over its safety and the ethics of administering it to girls as young as nine.

The vaccine manufactured by Merck & Co blocks two strains of the human papillomavirus (HPV 16 and 18) which are known to cause about 70% of cervical cancers.

The US Food and Drugs Administration authorised sale of the vaccine in that country in June 2006. The company launched it in India in October 2008 and followed it with television advertisements that tend to make the parents believe that their daughters risk dying of cervical cancer if not vaccinated.

Advertising prescription drugs on television is unethical enough, but using fear to sell them is worse, according to medical scientists aware of the controversy in the US.

Gardasil is an efficient vaccine but the safety and risk information about it has not been made available to parents to enable them make an informed decision about vaccinating their daughters, says Kumaravel Somasundaram, a cancer expert at the Indian Institute of Science in Bangalore. "We did not debate the issues even within the science community before the vaccine arrived in the market," he said.

Its exorbitant listed price - $120 (Rs 5,800) per dose and three shots are required - is the least of the concerns about the vaccines, says Jacob Puliyel, consultant paediatrician at the St. Stephens Hospital in Delhi. "What bothers me is the reported side effect." A Google search with just two key words 'gardasil+safety' lists 263,000 reports relating to side effects.

As of August 31, the US Centres of Disease Control (CDC) had received more than 10,000 adverse event reports, including 27 deaths following Gardasil vaccination. According to CDC, seizures, blood clots and paralysis accounted for six% of adverse events classified as "serious", while fainting, fever and headaches made up the rest. But the US health officials and Merck have dismissed the adverse events as "unrelated to the vaccine" and have claimed that the vaccine is safe.

Puliyel says the Gardasil vaccination raises an ethical issue as it can only prevent, but not treat HPV infection. Since HPV is sexually transmitted, the vaccine needs to be given before a girl becomes sexually active - ideally at the age of 11. "The underlying assumption here is that adolescent girls in India may all become promiscuous," says Puliyel.

An August 21 editorial in the New England Journal of Medicine noted that Gardasil's "long-term effectiveness is unclear" since no participants have been followed for more than five years while most cervical cancers take 10 years to develop.

"While it has been shown that the HPV vaccines prevent pre-cancerous lesions, we don't know if they will prevent cancer itself," the editorial said.

The journal also raised two other questions: One, most HPV infections clear on their own in 1-2 years through the body's natural immune response. Will the vaccine interfere with this natural process and, if so, in what ways? Two, since only two of the cancer causing strains of HPV are suppressed by Gardasil, will other strains take their place? More than 160 types of HPV are known to exist.

"With so many essential questions still unanswered, there is good reason to be cautious about introducing large-scale vaccination programmes (with Gardasil)," says Charlotte Haug, editor in chief of the Journal of the Norwegian Medical Association.

"There is too little long-term safety and efficacy data, especially in young girls," says Tom Fitton, president of Judicial Watch, a public interest group in Washington. "It looks as if an unproven vaccine with dangerous side effects is being pushed as a miracle drug."

Merck spokesperson Vince Docherty however told IANS that the vaccine was tested in approximately 25,000 people in the United States and around the world, "and found to be safe and effective in preventing serious HPV-related diseases".

According to the company, the vaccine launched in India can be given to women from age 10 to 26. The office of the Drug Controller General of India did not reply to questions on how the vaccine was allowed to be sold without the mandatory clinical trial on local population. The trial in the 16-23 age group, originally proposed by the Indian Council of Medical Research in early 2008, has not started for reasons not known.

The Merck spokesperson however said that Indian regulators approved the sale of Gardasil in July 2008 on the basis of "clinical efficacy and safety data" generated worldwide and the results of a clinical trial carried out in India in 2007 in 110 healthy girls in the 9-15 age group. The company had outsourced the trial to unnamed contract research organisations and the results have not been published. The Merck official said the results are "in the process" of being published.

According to the American Cancer Society, virtually all cervical cancers can be prevented if any pre-cancerous cells detected during routine "Pap" test are treated immediately. The Pap test that costs about Rs 200 can detect changes on a woman's cervix even before cancer develops, when it is most curable. Between 1955 and 1992 the number of cervical cancer deaths in the United States dropped by 74% by the use of Pap test alone, without any vaccination.

The American vaccine watchdog, Virginia-based National Vaccine Information Center, has cautioned that Gardasil vaccine could lull people into a false sense of security. It says that since the vaccine protects only against a few strains of HPV responsible for 70% of cervical cancers, "it will be important for women to continue getting screened by regular Pap tests" to guard against the remaining 30% of cervical cancers caused by other dangerous strains of HPV.

Critics say that the Indian health ministry which acted so fast to put the controversial Merck vaccine on chemist shops ahead of the clinical trial (in the 16-23 age group) should have instead promoted the inexpensive Pap test across the nation if it was really serious about reducing cervical cancer deaths.