Protecting the Herd from H1N1

摘要

Herd immunity-the concept that high vaccination cover-age can provide partial or even complete protection to those not vaccinated-has been a component of vaccination policy for more than 50 years (1,2). J. Medlock and A. P. Galvani ("Optimizing influenza vaccine distribution," Reports, 25 September, p. 1705) applied this concept to the current H1N1 situation and concluded that officials should target vaccination to those that contribute the greatest transmission (school-age children and their parents) rather than focusing on high-risk individuals, thus indirectly protecting high-risk groups through herd immunity.