Pneumonia hospitalisation incidence rate in vaccinated and unvaccinated groups
| PYs | No. of subjects with pneumonia hospitalisation | No. of pneumonia hospitalisations | IR | 95% CI | |
| With PPSV23 | 705.98 | 36 | 52 | 73.66 | 53.64 to 93.68 |
| Without PPSV23 | 1375.00 | 105 | 162 | 117.82 | 99.68 to 135.96 |
| Total | 2080.98 | 141 | 214 | 102.84 | 89.06 to 116.61 |
IR, incidence rate, calculated as the ratio of the number of pneumonia hospitalisations per 1000 PYs of follow-up; PPSV23, 23-valent pneumococcal polysaccharide vaccine; PY, person-year.