Peer-reviewed article
Effect of pneumococcal conjugate vaccine booster dose on prevention of invasive pneumococcal disease in British Columbia, 2003-2018.
Chia-Yuan Chang, Sharifa Nasreen, Manish Sadarangani, Jacquelyn J Cragg, Fawziah Marra ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study examined how well pneumococcal conjugate vaccines prevent serious bacterial infections in children in British Columbia, Canada between 2003 and 2018. Researchers compared infection rates among children who were unvaccinated, received primary vaccine doses only, or received primary doses plus a booster dose. Children who received the full vaccine schedule with a booster had the lowest rates of invasive pneumococcal disease, with significantly better protection than those who received primary doses alone.
Key points
- Unvaccinated children had an annual incidence of 36.1 invasive pneumococcal disease cases per 100,000; primary-only vaccinated children had 11.6 per 100,000; and primary plus booster had 4.6 per 100,000
- The booster dose reduced disease incidence by 61% compared to primary-only vaccination
- Full vaccination (primary + booster) provided 87% protection compared to unvaccinated children
- Protection patterns were consistent across all age groups and serotype groups studied
- No significant differences in vaccine effectiveness were observed between the PCV7 vaccine era (2003-2010) and PCV13 era (2010-2018)
Limitations
This is an observational study using surveillance data and immunization registries, so causation cannot be definitively established and confounding factors related to vaccination status may influence results. The study does not evaluate vaccine safety or address reasons why some children remained unvaccinated or did not complete the full schedule.
Abstract
BACKGROUND: Invasive pneumococcal disease (IPD) remains a major cause of morbidity in children despite the routine use of pneumococcal conjugate vaccines (PCVs) in childhood immunization programs. While the effectiveness of different vaccination schedules is well established, the additional benefit of the booster dose remains unknown. This study estimated the incidence of IPD by vaccination status in children under 18 years of age in British Columbia (BC), Canada, from 2003 to 2018. METHODS: IPD cases were identified through laboratory surveillance and vaccination records obtained from provincial immunization registries. We estimated annual IPD incidence using Poisson regression, with the offset being the population at risk derived from immunization coverage rates. We calculated adjusted incidence rate ratios (aIRRs) stratified by serotype group, age, and vaccine period. RESULTS: Among 598 IPD cases, 53.2 % were unvaccinated, 31.8 % received 2-3 primary doses and 1 booster dose (primary + booster), 15.1 % received 1-3 primary doses (primary only). Annual adjusted incidence per 100,000 was 36.1 (unvaccinated), 11.6 (primary only), and 4.6 (primary + booster). Compared to unvaccinated children, aIRRs were 0.13 (95 % CI: 0.10-0.17) for primary + booster and 0.32 (95 % CI, 0.22-0.48) for primary only. The primary + booster group had a 61 % lower incidence than the primary-only group (aIRR 0.39, 95 % CI: 0.26-0.60). These patterns were consistent across age groups (<12 months, 12-23 months, 2-4 years, 5-9 years, and 10-18 years) and serotype groups (PCV7, additional PCV13, and non-PCV13). No significant differences in aIRR were observed between PCV7 (2003-2010) and PCV13 (2010-2018) eras. CONCLUSIONS: A schedule including a booster dose was associated with a significantly lower incidence of IPD. These findings support promoting the full primary + booster (2 + 1) schedule to reduce IPD burden in children.