Reflection and Reaction 206 www.thelancet.com/infection Vol 9 April 2009 contrasted with the concentrated epidemic in men who have sex with men, offers false reassurance. It is important to remember that the homosexual groups are selling sex, not within each other, but to the general population. To the general public, therefore, homosexual groups serve as pockets of infection that can potentially spread to men from all walks of life. The notion that religion is protective against STDs must be interpreted with caution. Alefiyah Rajabali, *Syed H Ali Department of Biological and Biomedical Sciences, Aga Khan University Hospital, Karachi, Pakistan syed.ali@aku.edu We declare that we have no conflict of interest. 1 Guriro A. Pakistanis use 130m condoms yearly: firm’s marketing survey, 2008. http://www.dailytimes.com.pk/default.asp?page=2008%5C09% 5C17%5Cstory_17-9-2008_pg12_10 (accessed Feb 18, 2008). 2 Khan S, Bandyopadhyay A, Causey P. Risks and responsibilities: male sexual health and HIV in Asia and the Pacific international consultation. New Delhi, India, Sept 23–26, 2006. Summary report, 2006. http://www. risksandresponsibilities.org/TechnicalReport_Summary.pdf (accessed Feb 18, 2008). 3 Norris AE, Clark LF, Magnus S. Sexual abstinence and the sexual abstinence behavior scale. J Pediatr Health Care 2003; 17: 140–44. Prepandemic influenza vaccines We read the Personal View by Lance Jennings and colleagues 1 with great interest. We agree that the benefits obtained from the use of prepandemic vaccines should be balanced against the possible adverse effects. It is thought that prepandemic vaccination could decrease the basic reproductive number of a pandemic outbreak, 2–4 and thus retard the spread of infection. There is an ongoing discussion on the different approaches to the distribution of a prepandemic vaccine. 5 Given the current limitations of vaccine manufacturing methods, prepandemic vaccination campaigns should probably be applied to a limited proportion of the population. However, as mentioned above, there are potential adverse outcomes to prepandemic vaccines. The antigens contained in the prepandemic vaccine could poorly or partly match the antigens of the pandemic strain, which could induce a state of partial protection against the pandemic virus—avoiding fatal infection and leading to a milder or incomplete form of the disease. In this scenario, it would be more difficult to identify new cases of influenza infection. Transmissibility could even increase, since the milder infection would have a more limited impact on the patient’s activities (eg, work, travel) allowing wider dissemination of the virus. Jennings and colleagues speculate on the introduction of an H5N1 antigen into existing seasonal influenza vaccines. On the basis of the current vaccination guidelines for seasonal influenza, only people included in the risk groups (ie, those older than 65 years, essential workers, and patients with chronic illness) would receive the vaccine. If a pandemic emerges, a high number of mild symptomatic carriers could arise from these groups. Mild cases could transmit the virus to younger or unprotected people—ie, health workers interact with a large number of people at risk (hospitalised, immunocompromised, and children)—who are not included in the seasonal vaccination programmes. Developed countries, with a considerable percentage of elderly people, would be the most affected. A strategy based on a sequential vaccination of successive layers of the population could represent a valid approach. But, who should be the first to receive the vaccine? In the event of a pandemic, elderly people Philippe Benoist/Eurelios/Science Photo Library Chickens confined to prevent their exposure to the H5N1 virus in wildfowl