In this study, the investigators will prospectively assess fever rates and other associated vaccine adverse events in 6-23 month old patients during days 0-7 after administration of trivalent inactivated influenza vaccine (TIV) and 13-valent pneumococcal conjugate vaccine (PCV13) concomitantly compared to those who receive trivalent inactivated influenza vaccine (TIV) or 13-valent pneumococcal conjugate vaccine (PCV13) administered non-concomitantly. The investigators hypothesize that fever rates will be significantly higher during the 0-1 days after vaccination when inactivated influenza vaccine (TIV) and 13-valent pneumococcal conjugate vaccine (PCV13) are given concomitantly than when TIV or PCV13 is administered non-concomitantly.