Cheap shots — typhoid vaccine shows broad coverage
A new trial suggests that a shot confers immunity across age groups for three years.
By Nathan Seppa
An inexpensive vaccine against typhoid fever offers protection across age groups and is particularly effective in preschool-age children, a large trial in India finds. The same study shows that vaccinating half the people in a neighborhood confers significant protection throughout its population, researchers report in the July 23 New England Journal of Medicine.
Despite the availability of two approved vaccines, many countries have lagged in their efforts to confront typhoid, which strikes 21 million people each year and causes 200,000 to 600,000 deaths worldwide.
In the new study, an international team took an unusual approach to gauge the public health effect of one of the vaccines. In late 2004, the researchers vaccinated more than 37,000 people in the slums of Calcutta. People in some neighborhoods received an injection of a typhoid vaccine called Vi, while half the people in other neighborhoods, serving as a control sample, received hepatitis A vaccinations.