CAD and susceptibility to pneumonia measurement: Increasing numbers of strain-specific CPS were added to further itinerations of the vaccine to increase its efficacy, culminating into a 23-valent CPS antigen vaccine first licensed in 1983, protecting vaccinated adults against 87% of S. pneumoniae disease in the USA (Grabenstein and Klugman, 2012; Cavallari and De Libero, 2017).