TABLE 1

Interruption Time Points for Hypothesized Population-Level Changes in Denmark Related to Antibiotic Use Among Infants

InterruptionDate of Publication or RolloutFirst Birth Cohort to Experience Potential Interruption Effect (Negatively Lagged)Intended Effect and Description of Interrupting Policy or Event
IRF bulletinApril 1, 2007April 1, 2006Nationwide bulletin to advocate rational antibiotic prescribing among GPs. It stated that antibiotics nominally affect the duration of acute otitis media infection and do not prevent adverse sequelae (eg, mastoiditis or recurrent acute otitis media). For antibiotic treatment of acute otitis media in children, it recommended primary treatment with penicillin V, a narrow-spectrum antibiotic38; after penicillin V failure, the secondary recommendation was for amoxicillin,24 which has a broader spectrum of antibacterial activity than penicillin V.38
PCV7 “catch-up” programOctober 1, 2007May 1, 2006Danish childhood vaccination program granted cost-free enrollment in PCV7 program for children between 3 and 17 mo of age. Vaccination is intended to reduce incidence of invasive pneumococcal disease, pneumococci-related upper and lower respiratory infection, and transition of pneumococci in the general population. Children in this group who received their first PCV7 vaccination before their first birthday were offered a second PCV7 course after a minimum 1-mo interval and a third after 2 more months minimum. Children who received their first course after their first birthday were offered 1 additional course after a minimum 2-mo interval.2527
Standard PCV7 programOctober 1, 2007July 1, 2007Danish childhood vaccination program granted cost-free enrollment in PCV7 program for children <3 mo of age on October 1, 2007, onward. A series of 3 PCV7 courses at 3, 5, and 12 mo of age, concurrent with the DTaP/IPV/Hib vaccination.2527
Transition from PCV7 to PCV13April 19, 2010January 19, 2010Danish childhood vaccination program granted cost-free enrollment in PCV13 program for children <3 mo of age on April 19, 2010, onward; however, the program recommended using all PCV7 stocks before initiating PCV13. PCV13 dissemination was therefore gradual during 2010.27
Standard PCV13 programJanuary 1, 2011October 1, 2010Danish childhood vaccination program granted cost-free enrollment in PCV13 program for children <3 mo of age. After gradual depletion of PCV7 stocks during 2010, PCV13 was predominant nationwide by 2011.27
  • DTaP/IPV/Hib, diphtheria, tetanus, acellular pertussis, polio, and Haemophilus influenzae type b.