Nowadays a 13-valent pneumococcal conjugate vaccine, Prevnar 13 (PCV13), is used widely to vaccinate children. This vaccine contains the seven serotypes present in PCV7 (4, 6B, 9V, 14, 18C, 19F and 23F) plus the emerging serotypes 1, 3, 5, 6A, 7F and 19A.(2) In the Netherlands however the 10-valent pneumococcal conjugate vaccine, Synflorix (PCV10), is still used to vaccinate children in the national infant vaccination.(3)