Vaccines have greatly increased life expectancy in every country in which they have been introduced. Between 1924 and 2013, an estimated 103.1 million cases of contagious disease were prevented by vaccines in the United States alone.1 Streptococcus pneumoniae is the leading cause of human bacterial pneumonia worldwide, likely causing ∼50% of all community-acquired pneumonia.2 It is a cause of otitis media and also potentially fatal disseminated pediatric infections, which kill an estimated 1 million children globally each year.