As director of the human papillomavirus (HPV) vaccines project at the global health non-profit organization PATH, I wish to clarify some important points relating to your News story on the inquiry committee's investigation of the HPV vaccine study following the deaths of participants (Nature 474, 427–428; 2011). There were seven deaths (among nearly 24,000 girls), not four, and the inquiry committee found that none of the deaths was related to the vaccine (five definitively, two considered unlikely).

Contrary to your headline indicating that the ethics of the study have been criticized, the inquiry committee's report concludes: “There has been no major violation of any ethical norm in the conduct of the study.”

PATH believes that the HPV vaccine study under review was not a 'clinical' trial because no clinical outcomes were measured. The product had already undergone clinical trials in India and elsewhere, and had been licensed and made available in the private sector throughout the country. Even so, safeguards such as ethical review and informed consent were built into the study.

You quote Jacob Puliyel's opinion that not enough is known about the burden of HPV-related cervical cancer in India. However, the World Health Organization estimates that India shoulders more than one-quarter of the global burden of cervical-cancer mortality (about 73,000 of 275,000 deaths per year). The HPV types countered by the vaccines in question account for the majority of these cases. It was in part owing to the high prevalence of cervical cancer in the country that PATH included India among its four study sites (similar studies were conducted in Peru, Uganda and Vietnam).

Prevention methods such as HPV vaccination and screening alternatives (by visual inspection or HPV DNA testing) could substantially reduce the mortality in middle- and low-income countries, which suffer about 88% of the burden of cervical cancer, to the low levels now common elsewhere.

To increase cost-effectiveness, we need evidence of the best way to roll out these interventions. Studies such as those completed in India (see http://www.rho.org) will enable the acquisition of such data.