Assessing prescription of antibiotics after vaccination against pneumococcal pneumonia; using prescription sequence symmetry analysis.

OBJECTIVES

Prescription sequence symmetry analysis (PSSA) is used to detect adverse event signals using administrative claims databases. In this study, we investigated whether PSSA can be applied to gauge the effects of PCV13 vaccination on antibiotic prescription rates in elderly patients.

METHODS

We studied prescription records of patients aged 65 or older between 1 January 2014 and 31 December 2020, from the Helsana Swiss claims database. PSSA was performed to explore the relationship between 13-valent pneumococcal conjugate vaccine (PCV13) and six antibiotics recommended by the Swiss Society of Infectious Diseases for community-acquired pneumonia treatment (amoxicillin-clavulanate, azithromycin, clarithromycin, doxycycline, levofloxacin, and moxifloxacin), three additional antibiotics (amoxicillin, ciprofloxacin, and fosfomycin), and ten control drugs.

RESULTS

Amoxicillin-clavulanate, clarithromycin, and levofloxacin were more likely to be prescribed before than after vaccination, for all time windows between 25 and 104 weeks. Adjusted sequence ratio (ASR) values ranged from 0.599 to 0.614, 0.508 to 0.568, and 0.514 to 0.752, respectively. Lower prescription rates after vaccination were also observed for azithromycin (all time windows between 38 and 104 weeks, ASR 0.705-0.739) and moxifloxacin (all time windows between 52 and 104 weeks, ASR 0.658-0.772). PCV13 did not have statistically significant associations with doxycycline, amoxicillin, ciprofloxacin, fosfomycin, or any of the ten controls.

DISCUSSION: The lower prescription rate of antibiotics for community-acquired pneumonia after vaccination could be attributed to a protective effect of PCV13. This novel application of PSSA can be used to compare the real-world impact of other vaccines on drug consumption.