Update 1. Added more information about the power of the herd immunity written by Tara Haelle.
One of the most recent and important vaccines added to the current schedule of immunization is the rotavirus vaccine, introduced in the USA in 2007. Before the introduction of the vaccine, rotavirus was the most common cause of severe gastroenteritis in US children under 5 years old. Each year, rotavirus caused an estimated 20 to 60 deaths, 55,000 to 70,000 hospitalizations, and nearly half a million non-emergency visits to healthcare facilities.
A study, recently published the Pediatrics journal, concluded that, after the rotavirus vaccines was introduced, the numbers of diarrhea-related illness in US children dropped significantly. Moreover, probably as a result of herd immunity (where transmission through a population is inhibited by individual who are immune to the disease), the study found that the rate of hospitalizations related to the virus dropped substantially in both vaccinated and unvaccinated children.
The research examined health insurance data from across the USA (except for Medicaid, and a few states that don’t report data) for children under 5 years, cross tabulating various gastrointestinal illnesses with hospitalizations and other medical care. It also compared the same information to the vaccination status of those children. Finally, they gathered data about these illnesses from 2001 through 2006 (before the vaccine was introduced) and 2007-11, to compare hospitalization and other medical facility encounters between the pre- and post-vaccine groups. Continue reading “Why we immunize–protect children from hospitalization for diarrhea”