A cost-effectiveness analysis of vaccinating older adults with the 23-valent pneumococcal polysaccharide vaccine (PPV23) compared to no vaccination, the 13-valent pneumococcal conjugate vaccine (PCV13), or PCV13 followed by PPV23 in Colombia. (August 2018) - Prieto, E.; Jiang, Y.; Yang, X.; Graham, J.B.; Monsanto, H.; Ruiz, J.; Beltrán, C.; Rojas, M.