Microbial aetiology of paediatric pneumonia complicated with parapneumonic effusion in the era of pneumococcal vaccination

Pediatric parapneumonic effusion before and after national pneumococcal vaccination programs in Taiwan

BACKGROUND

Reports on the effectiveness of pneumococcal conjugate vaccines (PCVs) on pediatric parapneumonic effusion are limited. We report the changes in cases and etiologies of pediatric parapneumonic effusion in a children's hospital before and after national PCV13 vaccination programs.

METHODS

We screened medical records of children 0-18 years admitted to the National Taiwan University Hospital with diagnoses of lobar pneumonia and parapneumonic effusion between 2008 and 2017. Patients with effusion analyses were included. Results of blood, pleural fluid, and respiratory specimens surveyed as standard care were analyzed.

RESULTS

Diagnostic testing revealed at least a pathogen in 85% of 202 children with lobar pneumonia and parapneumonic effusion. After national PCV13 immunization, pneumococcal empyema decreased by 72% among 2- to 5-year olds. Mycoplasma pneumoniae was the second most common etiology. There were marked differences in effusion characteristics, metabolic, and respiratory parameters between children infected with pneumococcus and M. pneumoniae.

CONCLUSION

The effectiveness of the national PCV13 immunization programs on pneumococcal empyema was evident and remained substantial after 4 years in Taiwan. Continuous surveillance is important to monitor the emergence of other pathogens including non-PCV serotypes and M. pneumoniae.

Clinical features and inflammatory markers in pediatric pneumonia: a prospective study

In this prospective, observational study on previously healthy children <18 years, we aimed to study the diagnostic ability of clinical features and inflammatory markers to (i) predict pathologic chest radiography in suspected pneumonia and (ii) differentiate etiology in radiological proven pneumonia. In 394 cases of suspected pneumonia, 265 (67%) had radiographs consistent with pneumonia; 34/265 had proof of bacterial etiology. Of the cases, 86.5% had received pneumococcal conjugate vaccine. In suspected pneumonia, positive chest radiography was significantly associated with increasing C-reactive protein (CRP) values, higher age, and SpO₂ ≤92% in multivariate logistic regression, OR 1.06 (95% CI 1.03 to 1.09), OR 1.09 (95% CI 1.00 to1.18), and OR 2.71 (95% CI 1.42 to 5.18), respectively. In proven pneumonia, bacterial pneumonia was significantly differentiated from viral/atypical pneumonia by increasing CRP values and SpO₂ >92% in multivariate logistic regression, OR 1.09 (95% CI 1.05 to 1.14) and OR 0.23 (95% CI 0.06 to 0.82), respectively. Combining high CRP values (>80 mg/L) and elevated white blood cell (WBC) count provided specificity >85%, positive likelihood ratios >3, but sensitivity <46% for both radiographic proven and bacterial pneumonia.

CONCLUSION

With relatively high specificity and likelihood ratio CRP, WBC count and hypoxemia may be beneficial in ruling in a positive chest radiograph in suspected pneumonia and bacterial etiology in proven pneumonia, but with low sensitivity, the clinical utility is limited. What is Known: • Pneumonia is recommended to be a clinical diagnosis, and neither clinical features nor inflammatory markers can reliably distinguish etiology. • The etiology of pneumonia has changed after routine pneumococcal conjugate vaccine. What is New: • High CRP and WBC counts were associated with infiltrates in children with suspected pneumonia and with bacterial infection in proven pneumonia. • In the post-pneumococcal vaccination era, viral etiology is expected, and in cases of pneumonia with low CRP and WBC counts, a watch-and-wait strategy for antibiotic treatment may be applied.