Introduction: Between September 2014 and February 2015, the Netherlands Pharmacovigilance Centre Lareb received a high number of reports of Adverse Events Following Immunization (AEFIs) following administration of a pneumococcal polysaccharide conjugated 13-valent adsorbed vaccine (Pneu-13), mainly reports of injection site reactions with an unexpected time to onset (TTO) of 4-7 days. The reports came from a selected group of 21,000 people of 70 years or above, who participated as controls in the CAPiTA study [1, 2]. After unblinding controls were offered a Pneu-13 vaccination. Aim: The aim of this study is to evaluate differences in the number of AEFIs of injection site reactions in elderly and their characteristics like TTO after Pneu-13 vaccination, compared with reports of AEFIs following seasonal influenza vaccination in the same age group. Method: Reports of injection site reactions after Pneu-13 vaccination received between September 2014 and February 2015 were compared to reports of injection site reactions of elderly of 70 years or above vaccinated during the annual influenza campaign. Given the limited reports of elderly after influenza vaccination, reports of 5 consecutive years were selected. Results: Lareb received 390 reports after Pneu-13 vaccination concerning 616 AEFIs of which 296 injection site reactions (47.7 %). Injection site reactions with a TTO>2 days were reported 176 times (58.4 %), mostly 4-7 days. In the group of elderly 80 years or above these reactions were reported more often compared with elderly of 70-80 years; i.e. 69.0 vs. 53.8 % (crude OR 1.9, 95 % CI: 1.12-3.24). Between October 1, 2010 and May 1, 2014 Lareb received 136 spontaneous reports concerning 240 AEFIs after influenza vaccination, of which 46 injection site reactions (19.2 %). The proportion of injection site reactions with a TTO>2 days was 6.6 %. Conclusions: Even though the vaccines itself are not completely comparable, reports after Pneu-13 vaccination of elderly aged 70 and above, the proportion of AEFIs of injection site reactions after Pneu- 13 vaccination compared with influenza vaccination was relatively high. The proportion of reports of injection site reactions with a TTO >2 days was more outspoken in the Pneu-13 group as compared to the influenza group. Especially in elderly of 80 years this long TTO was more outspoken. Our findings indicate a possible increased risk for injection site reactions with a long TTO with increasing age after vaccination with pneumococcal polysaccharide conjugated 13-valent adsorbed vaccine.