Table 4.

Stratified analysis of the association between 23-valent pneumococcal polysaccharide vaccine (PPSV23) and multiple-serotype pneumococcal pneumonia

	Number of multiple-serotype versus single-serotype pneumonias	Crude OR (95% CI)	Adjusted OR* (95% CI)	P value for test of interaction†
Overall	133 vs 209	0.49 (0.29 to 0.83)	0.51 (0.27 to 0.94)	–
Stratified by sex
Male	74 vs 127	0.65 (0.35 to 1.22)	0.62 (0.30 to 1.29)	0.170
Female	59 vs 82	0.29 (0.11 to 0.77)	0.23 (0.07 to 0.80)
Stratified by age group (years)
<65	48 vs 51	0.63 (0.19 to 2.06)	0.97 (0.20 to 4.86)	0.790
≥65	85 vs 158	0.52 (0.29 to 0.94)	0.50 (0.25 to 1.01)
Stratified by underlying disorders
Present	75 vs 131	0.63 (0.34 to 1.16)	0.53 (0.25 to 1.12)	0.192
Absent	58 vs 78	0.27 (0.08 to 0.84)	0.24 (0.05 to 1.08)
Stratified by pneumonia type
CAP	116 vs 163	0.42 (0.23 to 0.76)	0.40 (0.20 to 0.82)	0.086
HCAP	17 vs 46	1.26 (0.41 to 3.87)	1.44 (0.26 to 8.04)
Stratified by chest radiograph findings
Lobar pneumonia	102 vs 153	0.43 (0.23 to 0.79)	0.37 (0.17 to 0.79)	0.360
Bronchopneumonia	31 vs 56	0.73 (0.28 to 1.96)	1.01 (0.29 to 3.52)

*ORs were adjusted for patient’s sex, age, age group, vaccination status, present smoking, underlying diseases, prehospital antibiotic use, study site, study period, pneumonia type, hypoxaemia and severity score (CURB-65).

†Wald test was used for the test of interaction.

CAP, community-acquired pneumonia; CURB-65, Confusion, blood Urea nitrogen, Respiratory rate, Blood pressure, 65 years of age and older; HCAP, healthcare-acquired pneumonia.