The vaccine promoted as a safeguard for girls against developing cervical cancer later in life has been linked with at least 20 deaths in the United States and hundreds of other serious adverse reactions. This is prevention, if you like, but not the sort most parents envisage.

The vaccine has been given to more than seven million girls and young women in the US, a large number of them 11- and 12-year-old schoolgirls, the New York Times reports.

Some 12,424 reports of adverse events were made to a voluntary government database. Of those, 6.2 per cent (772) were considered serious, according to a study published in the Journal of the American Medical Association. The most common serious complications were fainting and an increased risk for potentially fatal blood clots, possibly related to oral contraceptive use and obesity. There were 32 reports of death, but only 20 could be verified. Among those, other causes are implicated (diabetes, drug abuse, Lou Gehrig’s disease, flu and others) and it is not at all clear what are the risks of Gardasil for any individual girl.

The majority of the reports were filed by Merck and company, manufacturer of Gardasil, but most failed to provide enough information for further investigation, say the study authors. However, they are confident in recommending that people get the vaccine, which, they say, seems to be as safe as other vaccines.

Merck is also upbeat, saying that the study “confirms the very favourable safety profile we’ve seen in our extensive clinical trials”. Mind you, this is the company that wooed professional groups with grant money for educational programmes to promote the vaccine.

But an accompanying editorial in JAMA questioned whether any level of risk is acceptable for vaccination when there is an alternative way of preventing cervical cancer:

“There are not a huge number of side effects here, that’s fairly certain,” said the editorial writer, Dr. Charlotte Haug, an infectious disease expert from Norway, about the vaccine. “But you are giving this to perfectly healthy young girls, so even a rare thing may be too much of a risk.

“I wouldn’t accept much risk of side effects at all in an 11-year-old girl, because if she gets screened when she’s older, she’ll never get cervical cancer,” Dr. Haug said in an interview. “You don’t have to die from cervical cancer if you have access to health care.”

The other point is that you probably don’t have to die from cervical cancer if you avoid contracting the sexually transmitted disease -- human papillomavirus -- that is the precursor in the vast majority of cases. But HPV is now so widespread that there is no telling who has it.

Then again, should this really be a dilemma that parents and their young daughters have to face? Wouldn’t a truly rational response to the prevalence of HPV and other STDs be to redouble efforts to encourage chastity among young people?