Recurrent respiratory tract infections (RRTI) in the elderly: A late onset mild immunodeficiency?

Supporting vaccine (co)-administration decisions: Development and validation of a tool for assessing the risk of severe outcomes due to lower respiratory tract infections

OBJECTIVE

To develop and validate a score to predict the 90-day risk of hospitalization/death in patients with low respiratory tract infections (LRTIs) with the aim to support clinical decision making on vaccine (co)-administration.

METHODS

We formed a cohort of patients aged 18 years or older being diagnosed with LRTIs in the period between January 1, 2012 and December 31, 2022. Each patient was followed until occurrence of respiratory-related hospitalization/death up to the end of the study period (December 31, 2022). Along with age and sex, forty determinants were adopted to assemble the respiratory tract infection (RTI)-Health Search (HS) core using the development sub-cohort. The prediction accuracy of the score was therefore assessed in the validation sub-cohort.

RESULTS

We identified 252,319 patients being diagnosed with LRTIs (females: 54.7 %; mean age: 60 (SD:18.1)). When the risk of LRTIs-related hospitalizations/deaths was estimated via RTI-HScore, its predicted value was equal to 1.4 % over a 90-day event horizon. The score showed explained variation and discrimination accuracy were equal to 45 % (95 % CI: 44-47 %) and 81 % (95 % CI: 79-84 %), respectively. The calibration slope did not significantly differ from the unit (p = 0.8314).

CONCLUSIONS

The RTI-HScore was featured by good accuracy for prediction of LRTIs-related complications over a 90-day follow-up. Such a tool might therefore support general practitioners to enhance patients' care by facilitating approaches for (co)-administration of vaccines for respiratory infections through a score-based decision support system.

The burden of recurrent respiratory tract infections in adult population: a population-based study in primary care

BACKGROUND

Viral infections are the main original cause of recurrent respiratory tract infections (RRTIs), but their complications and recurrences are due to bacteria as well. While some operational definitions and epidemiology of RRTIs are reported in paediatrics, no similar definitions have been proposed for adults.

AIM

To assess the epidemiology and characteristics of RRTIs in the adult population.

DESIGN AND SETTING

Cohort study in the primary care setting.

METHODS

Using the Health Search Database, we selected a cohort of patients aged 18 years or older between 2002 and 2022. Yearly, we counted upper and lower respiratory tract infections (RTIs) per patient. We investigated 2 cut-offs defining RRTIs, nominally 3+ RRTIs/patient/year or greater than the mean value of RTIs/patient/year. The associations between these two event definitions and the correlates defining the patients' vulnerability were assessed by estimating a logistic regression model.

RESULTS

Over the study years, the mean number of RTIs/patient/year ranged from 0.07-0.16 or 1.10-1.13 events, when the denominator was formed by the overall population or those diagnosed with RTIs, respectively. When the analysis was focussed on 2022, we obtained 0.2% (1.3% among those with RTIs) or 13% (11.3% among those with RTIs) cases of RRTIs, using a cut-off of 3+ or >=0.16 events (mean value/patient), respectively. Consistent associations were found for these two operational definitions and the investigated clinical correlates.

CONCLUSION

We provided evidence on the epidemiology and concurrent/predisposing factors of RRTIs in adults. These data should support health authorities and general practitioners for the application of the most appropriate preventive and/or treatment strategies.

Application of vaccine response in the evaluation of patients with suspected B-cell immunodeficiency: Assessment of responses and challenges with interpretation

Diagnostic vaccination is an integral component in the evaluation of patients suspected to have a B cell or humoral deficiency. Evaluation of antibody production in response to both protein- and polysaccharide-based vaccines aids in distinguishing between specific categories of humoral deficiency. Although assessment of pneumococcal polysaccharide responses is widely available and included in diagnostic guidelines, significant variability still exists in the measurement and interpretation of these responses. Interpretation can also be complicated by age, vaccination history and treatment with immunoglobulin replacement therapy. Despite the challenges and limitations of evaluating pneumococcal polysaccharide vaccine responses, it can provide valuable diagnostic and prognostic information to guide therapeutic intervention. Future efforts are needed to further standardize measurement and interpretation of pneumococcal antibody responses to vaccination and to identify and establish other methods and/or vaccines as alternatives to pneumococcal vaccination to address the challenges in certain patient populations.

Specific Antibody Deficiencies in Clinical Practice

Specific antibody deficiency (SAD) is defined as the inability to mount an antibody response to purified Streptococcus pneumoniae capsular polysaccharide antigens in the presence of normal immunoglobulin concentrations and normal antibody responses to protein antigens. In this review, we discuss the difficulties in using presently available testing methods to adequately define SAD. The fact that there are different forms of SADs to pneumococcal surface polysaccharides is detailed. The diagnostic and therapeutic implications of recognizing that, in addition to SAD, there are other forms of SAD in the response to S. pneumoniae polysaccharides are described in detail. The conclusion of this review is that assessment of immunity and therapeutic actions to deal with SADs need to be based on clinical evidence rather than solely on arbitrarily defined antibody responses.

Triptych of the Hermit Saints: pneumococcal polysaccharide vaccines for the elderly

Pneumococcal pneumonia is a serious disease with considerable morbidity and mortality in the elderly. Despite adequate antibiotic treatment, the long-term mortality of pneumococcal pneumonia remains high. Preventive measures in the form of vaccination, therefore, are warranted. Twenty-three-valent polysaccharide vaccines have a broad coverage but limited efficacy. Pneumococcal conjugate vaccines have been shown in children to be able to prevent invasive and mucosal pneumococcal diseases. It should be realized that the serotype composition of current pneumococcal conjugate vaccines is not tailored for the elderly, and that replacement disease can occur. Yet, the current 13-valent conjugate vaccine has been shown to protect against infections with vaccine serotypes. Long-term mortality of pneumococcal pneumonia should be included in policy making about the introduction of these vaccines for the elderly.