Distribution of respiratory pathogens in children with CAP (cases) and healthy children (controls), unadjusted and adjusted OR and population-attributable fraction for each respiratory pathogen, Perth, Western Australia, May 2015–October 2017
| Parameter | Case (%), (n=230) | Control (%), (n=230) | Unadjusted OR (95% CI) | Adjusted OR (95% CI)* | Population-attributable fraction estimate, % (95% CI) |
| Respiratory virus | |||||
| Influenza (any) | 16 (6.9) | 3 (1.3) | 5.6 (1.6 to 19.6) | 10.1 (1.8 to 57.1) | 6.2 (2.5 to 9.7) |
| Influenza A H1N1 | 4 (1.7) | 1 (0.4) | 4.0 (0.4 to 36.5) | 23.1 (1.2 to 442.6) | |
| Influenza A H3 | 9 (3.9) | 1 (0.4) | 9.3 (1.1 to 74.2) | 9.6 (0.7 to 119.7) | |
| Influenza B | 3 (1.3) | 1 (0.4) | 3.0 (0.3 to 29.3) | 2.7 (0.1 to 43.9) | |
| RSV | 46 (20.0) | 3 (1.3) | 18.9 (5.7 to 61.8) | 58.4 (15.6 to 217.5) | 20.2 (14.6 to 25.5) |
| HPIV (any) | 11 (4.7) | 0 | – | – | – |
| HPIV1 | 6 (2.6) | 0 | – | – | – |
| HPIV2 | 0 | 0 | – | – | – |
| HPIV3 | 5 (2.1) | 0 | – | – | – |
| Rhinovirus | 35 (15.2) | 48 (20.8) | 0.7 (0.4 to 1.1) | 1.3 (0.6 to 2.6) | 3.6 (- 0.05 to 12.2) |
| HMPV | 23 (10) | 2 (0.8) | 12.6 (2.9 to 54.3) | 37.2 (7.8 to 177.7) | 9.8 (5.6 to 13.7) |
| Adenovirus | 10 (4.3) | 3 (1.3) | 3.4 (0.9 to 12.6) | 12.1 (1.4 to 104.4) | 4 (1.1 to 7.1) |
| Coronavirus (any) | 8 (3.4) | 11 (4.7) | 0.7 (0.2 to 1.8) | 0.8 (0.1 to 4.4) | |
| Coronavirus OC43 | 5 (2.1) | 3 (1.3) | 0.6 (0.1 to 2.5) | 0.7 (0.1 to 3.9) | |
| Coronavirus NL63 | 4 (1.7) | 3 (1.3) | 1.3 (0.3 to 6.0) | 1.5 (0.1 to 21.8) | |
| Coronavirus HKU1 | 1 (0.4) | 2 (0.8) | 0.5 (0.04 to 5.5) | 0.5 (0.0 to 2724.1) | |
| Coronavirus 229E | 0 | 1 (0.4) | – | – | |
| At least one respiratory virus identified | 130 (56.5) | 66 (28.6) | 3.2 (2.1 to 4.7) | 4.7 (2.8 to 7.8) | 44.4 (33.8 to 53.3) |
| One virus | 111 (48.2) | 62 (26.9) | |||
| Two or more viruses | 19 (8.2) | 4 (1.7) | |||
| Bacteria | |||||
| Streptococcus pneumoniae | 59 (25.3) | 61 (26.5) | 0.9 (0.6 to 1.4) | 0.6 (0.3 to 1.4) | |
| Haemophilus influenzae | 75 (32.6) | 61 (26.5) | 1.3 (0.8 to 2.0) | 0.9 (0.4 to 1.7) | |
| Moraxella catarrhalis | 103 (44.7) | 144 (62.6) | 0.4 (0.3 to 0.7) | 0.6 (0.3 to 1.1) | |
| Staphylococcus aureus | 38 (16.5) | 36 (15.6) | 1.0 (0.6 to 1.7) | 1.3 (0.6 to 2.9) | |
| Mycoplasma pneumoniae | 19 (8.2) | 1 (0.4) | 20.6 (2.7 to 155.3) | 14.5 (2.2 to 94.8) | 7.2 (3.5 to 10.8) |
| Chlamydophila pneumoniae | 0 | 1 (0.4) | – | ||
| At least one species of bacteria identified | 165 (71.7) | 183 (79.5) | 0.6 (0.4 to 1.0) | 0.7 (0.4 to 1.2) | |
| One bacteria | 69 (30.0) | 88 (38.2) | |||
| Two or more bacterial species | 96 (41.7) | 95 (41.3) | |||
*Adjusted for age group, gender, prematurity, aboriginal status, comorbidity, childcare attendance, smoker at household, antibiotic exposure in last 7 days of enrolment and presence of other pathogens.
CAP, community-acquired pneumonia; HMPV, human metapneumovirus; HPIV, human parainfluenza virus; RSV, respiratory syncytial virus.