Increased incidence of adult pneumococcal pneumonia during school holiday periods

Alterations in the prevalence and serotypes of Streptococcus pneumoniae in elderly patients with community-acquired pneumonia: a meta-analysis and systematic review

BACKGROUND

Pneumococcal pneumonia is a common disease with a significant impact on morbidity and mortality among the elderly population. The main purpose of this meta-analysis was to estimate the prevalence of community-acquired pneumonia (CAP) in elderly individuals caused by Streptococcus pneumoniae (S. pneumoniae).

METHODS

A systematic search of the PubMed, Web of Science, and Scopus databases was conducted for relevant studies published between January 2013 and December 2023. Subgroup analysis and meta-regression were used to identify the sources of heterogeneity affecting the 87,430 patient studies obtained from 47 papers that met the inclusion and exclusion criteria.

RESULTS

The combined prevalence rate for S. pneumoniae among all CAP patients included in the study was 14.8% (95% confidence interval [CI]: 12.3-17.8%). The 5-year pooled prevalence decreased from 16.5% (95% CI: 15.0-18.2%) in 1996-2000 to 8.4% (95% CI: 6.3-11.0%) in 2016-2020 for bacterial culture alone and from 17.4% (95% CI: 16.3-18.7%) to 13.5% (95% CI: 10.7-16.8%) for bacterial culture and urinary antigen testing (UAT) combined (P < 0.001). The most prevalent serotype was serotype 3, followed by serotypes 8, 19 A, 22 F, 11 A, 5, 9 N, 12 F, 6 A, and 10 A. The vaccine-serotype coverage was 53.5% for PCV 13, 60.5% for PCV 15, 85.2% for PCV 20 and 88.6% for PPSV 23.

CONCLUSION

These findings indicate a decrease in the overall burden of pneumococcal CAP among elderly individuals over the decade, which lends support to the proposition that the delivery of immunization should be expanded across the life course.

Effectiveness of the 23-valent pneumococcal polysaccharide vaccine against vaccine serotype pneumococcal pneumonia in adults: A case-control test-negative design study

BACKGROUND

Vaccination with the 23-valent pneumococcal polysaccharide vaccine (PPV23) is available in the United Kingdom to adults aged 65 years or older and those in defined clinical risk groups. We evaluated the vaccine effectiveness (VE) of PPV23 against vaccine-type pneumococcal pneumonia in a cohort of adults hospitalised with community-acquired pneumonia (CAP).

METHODS AND FINDINGS

Using a case-control test-negative design, a secondary analysis of data was conducted from a prospective cohort study of adults (aged ≥16 years) with CAP hospitalised at 2 university teaching hospitals in Nottingham, England, from September 2013 to August 2018. The exposure of interest was PPV23 vaccination at any time point prior to the index admission. A case was defined as PPV23 serotype-specific pneumococcal pneumonia and a control as non-PPV23 serotype pneumococcal pneumonia or nonpneumococcal pneumonia. Pneumococcal serotypes were identified from urine samples using a multiplex immunoassay or from positive blood cultures. Multivariable logistic regression was used to derive adjusted odds of case status between vaccinated and unvaccinated individuals; VE estimates were calculated as (1 - odds ratio) × 100%. Of 2,357 patients, there were 717 PPV23 cases (48% vaccinated) and 1,640 controls (54.5% vaccinated). The adjusted VE (aVE) estimate against PPV23 serotype disease was 24% (95% CI 5%-40%, p = 0.02). Estimates were similar in analyses restricted to vaccine-eligible patients (n = 1,768, aVE 23%, 95% CI 1%-40%) and patients aged ≥65 years (n = 1,407, aVE 20%, 95% CI -5% to 40%), but not in patients aged ≥75 years (n = 905, aVE 5%, 95% CI -37% to 35%). The aVE estimate in relation to PPV23/non-13-valent pneumococcal conjugate vaccine (PCV13) serotype pneumonia (n = 417 cases, 43.7% vaccinated) was 29% (95% CI 6%-46%). Key limitations of this study are that, due to high vaccination rates, there was a lack of power to reject the null hypothesis of no vaccine effect, and that the study was not large enough to allow robust subgroup analysis in the older age groups.

CONCLUSIONS

In the setting of an established national childhood PCV13 vaccination programme, PPV23 vaccination of clinical at-risk patient groups and adults aged ≥65 years provided moderate long-term protection against hospitalisation with PPV23 serotype pneumonia. These findings suggest that PPV23 vaccination may continue to have an important role in adult pneumococcal vaccine policy, including the possibility of revaccination of older adults.

Seasonal Incidence of Community-acquired Pneumonia: A Retrospective Study in a Tertiary Care Hospital in Kathmandu, Nepal

Introduction

Community-acquired pneumonia (CAP) is the major cause of death in adult and elderly persons with a variety of presentations. Seasonal variation in the incidence of the disease is essential for clinicians and epidemiologists who deal with such diseases. The study was aimed at analysing the clinical profile and outcomes of community-acquired pneumonia during different seasons of the year in a tertiary care hospital, Manmohan Memorial Teaching Hospital (MMTH), of Kathmandu, Nepal.

Method

The aetiology and clinical profile of 378 patients with CAP who were admitted to MMTH over a period of one year were taken into account in this retrospective cross-sectional hospital-based study. Data were retrieved from the hospital medical records section and the Department of Pathology. All patients with a primary diagnosis of CAP admitted to the hospital were included in the study. Monthly and seasonal trends, aetiology, comorbidities, and mortality rates were analysed.

Results 

Of 378 patients with CAP, 160 patients (42.3%) had associated chronic obstructive pulmonary disease (COPD), 92 patients (24.3%) had hypertension (HTN), 59 patients (15.6%) had diabetes, 12 patients (3.1%) had active pulmonary tuberculosis, seven patients (1.85%) had kidney disease, and the remaining 48 patients (12.6%) had only CAP. Seasonal variation of CAP was noted in 131 patients (35%) in the winter, 98 (26%) in autumn, 86 (23%) in spring, and 63 patients (16%) in summer seasons. None of the patients were vaccinated against influenza and pneumococcus. The most common organism isolated in CAP was Acinetobacter calcoaceticus baumannii (ACB) complex (4.7%), which was more distinguished in the winter season. The second most isolated organism was Pseudomonas aeruginosa (2.6%). The most common clinical presentation was fever (63%), followed by cough (47%) and shortness of breath (47%). Sputum culture was found to be positive in 51 cases (13.4%). Among 378 patients, 78 patients (20.6%) received treatment in the Intensive Care Unit (ICU) and the rest of the patients received treatment in the general medical ward. The mortality rate was found to be 6.6%.

Conclusion

An incidence of sputum-positive CAP was found in 51 cases (13.4%). The most common organism was ACB complex, followed by Pseudomonas aeruginosa, which were sensitive to polymyxins. Both of them were predominant in the winter and spring.