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On behalf of the large number of investigators who participated in the monumental trial designed to evaluate the safety and efficacy of the human attenuated rotavirus vaccine Rotarix, I would like to thank Drs Kamal-Udin and Croft for their accurate summary of our study. Also, I completely agree with their appreciation of the significant disease burden associated with rotavirus worldwide, as well as the impact that the implementation of rotavirus vaccination can have in both the developing and industrialized world. We know today, in 2006, that rotavirus infects every child at least once before their 5th birthday and that, independent of the region, rich or poor, about 1 in 5 children will require a medical visit and 1 in 50–70 a hospitalization during their first 5 years of life (Emerg Infect Dis 2003;9:565–572; N Engl J Med 1996;335:1022–1028). Over 600,000 children die every year owing to rotavirus, mostly in the less developed regions of the world (Emerg Infect Dis 2006;12:304–306). The positive impact of safe and effective vaccines in this scenario, hopefully included in universal immunization programs, is quite clear.

When considering safety, pediatricians should be aware that with the widespread use of these vaccines, intussusception will occasionally occur in temporal association with vaccine administration, because intussusception is a naturally occurring syndrome. In a community where 10,000 infants are vaccinated, somewhere from 4 to 10 will develop idiopathic intussusception, mostly between 4 and 9 months of age (Pediatr Infect Dis J 2003;22:1–5; Pediatr Infect Dis J 2003;22:234–239; Pediatr Infect Dis J 2004;23:363–365). Such chance coincidental occurrences should not incriminate the vaccines. The medical community should be prepared to confront these cases appropriately. In reference to efficacy, I point out 2 issues: (1) The 42% reduction in gastroenteritis hospitalization rates for Rotarix observed in Latin America increased to 75% in a recent European trial (European Society of Pediatric Infectious Diseases, May 2006), indicating that the vaccine impact is influenced by regional differences; and (2) virus shedding for both vaccines cannot be compared because different methodologies were used; viral culture for Rotateq and enzyme-linked immunosorbent assay for Rotarix; using viral culture, the shedding of Rotarix is significantly lower and close to the range of Rotateq (GlaxoSmithKline, personal communication).

Within Latin America, Brazil, Venezuela, Panama, Mexico, and El Salvador have included or are soon to include the vaccine in their National Vaccine Programs. The experience in these countries and the associated impact in gastroenteritis-associated morbidity and mortality should help to pave the way for mass incorporation into national programs of more countries, especially those in development. Let’s hope so for the sake of the children.