Association of seasonal viral acute respiratory infection with pneumococcal disease: a systematic review of population-based studies

Abstract

ObjectiveAnimal and in vitro studies suggest that viral acute respiratory infection (VARI) can predispose to pneumococcal infection. These findings suggest that the prevention of VARI can yield additional benefits for the control of pneumococcal disease (PD). In population-based studies, however, the evidence is not in accordance, possibly due to a variety of methodological challenges and problems in these studies. We aimed to summarise and critically review the methods and results from these studies in order to inform future studies.MethodsWe conducted a systematic review of population-based studies that analysed the association between preceding seasonal VARI and subsequent PD. We searched MEDLINE, Embase and Global Health databases using tailored search strategies.ResultsA total of 28 studies were included. After critically reviewing the methodologies and findings, 11 studies did not control for seasonal factors shared by VARI and PD. This, in turn, could lead to an overestimation of the association between the two illnesses. One case–control study was limited by its small sample size (n case=13). The remaining 16 studies that controlled for seasonal factors suggested that influenza and/or respiratory syncytial virus (RSV) infections were likely to be associated with the subsequent occurrence of PD (influenza: 12/14 studies; RSV: 4/5 studies). However, these 16 studies were unable to conduct individual patient data-based analyses. Nevertheless, these studies suggested the association between VARI and subsequent PD was related to additional factors such as virus type and subtype, age group, comorbidity status, presentation of PD and pneumococcal serotype.ConclusionsPopulation-based studies do not give consistent support for an association between preceding seasonal VARI and subsequent PD incidence. The main methodological challenges of existing studies include the failure to use individual patient data, control for seasonal factors of VARI and PD, or include other factors related to the association (eg, virus, age, comorbidity and pneumococcal serotype).

Associations between common respiratory viruses and invasive group A streptococcal infection: A time‐series analysis

“…In the absence of individual‐level data on co‐infections, such time‐series analyses using population‐level data are an important tool for hypothesis generation and directing future in‐depth research. While time series have been used to estimate the association between respiratory virus infections and infections with another Streptococcus species ( Streptococcus pneumoniae ), such population‐level studies with GAS infections are very scarce. One such study, by Allard et al, reported a specific association between influenza B virus and GAS laboratory detections in Montréal, Canada.…”

Pathogenesis and prevention of risk of cardiovascular events in patients with pneumococcal community‐acquired pneumonia

“…Taken together, these findings, which are summarized in Table 2, may explain why preceding influenza virus infection, as well as infections caused by other types of respiratory viruses, leads to an increased bacterial burden in the airways, thereby contributing to both pneumococcal transmission and severity of disease [52][53][54][55][56].…”

Unraveling the seasonal epidemiology of pneumococcus

“…Acknowledging these limitations, our results nevertheless demonstrate that IPD incidence data contain dynamic information about the transmission of pneumococcal carriage. Second, different types and subtypes of influenza can vary in transmissibility and virulence and may have a different impact on pneumococcus (11). Future work could therefore extend the models proposed here to incorporate more detailed information on influenza viruses, if available.…”

“…In nontropical climates, IPDs typically display regular, marked seasonal variations, with a zenith of cases during winter and a nadir during summer (5)(6)(7)(8)(9). Previous work has examined candidate seasonal factors that could contribute to this pattern, such as climate (6,7,10), cocirculating pathogens [e.g., influenza viruses (11,12)], or variations of interindividual contact rates (13). Nevertheless, our understanding of pneumococcal seasonality remains fragmentary (4,14).…”