Does pneumococcal vaccine reduce influenza morbidity in humans?

SARS-CoV2 coronavirus: so far polite with children. Debatable immunological and non-immunological evidence

The reasons for the relative resistance of children to certain infections such as that caused by coronavirus SARS-CoV2 are not yet fully clear. Deciphering these differences can provide important information about the pathogenesis of the disease. Regarding the SARS-CoV2 virus, children are at the same risk of infection as the general population of all ages, with the most serious cases being found in infants. However, it has been reported that the disease is much less frequent than in adults and that most cases are benign or moderate (even with high viral loads), provided there are no other risk factors or underlying diseases. It is not clear why they have lower morbidity and virtually no mortality. A series of findings, relationships and behavioral patterns between the infectious agent and the child host may account for the lower incidence and a greatly attenuated clinical presentation of the disease in children.

Respiratory viral and pneumococcal coinfection of the respiratory tract: implications of pneumococcal vaccination

The interactions between Streptococcus pneumoniae and other respiratory pathogens have been studied in vitro, in animal models and in humans - including epidemiologic and vaccine probe studies. Interactions of pneumococcus with respiratory viruses are common, and many mechanisms have been suggested to explain this phenomenon. The aim of this review is to explore pneumococcal interactions with respiratory viruses and consider the potential role that the pneumococcal polysaccharide-protein conjugate vaccine may play in modifying pneumococcal-respiratory viral interactions.

Vaccines for preventing pneumococcal infection in adults

BACKGROUND

Diseases caused by Streptococcus pneumoniae (S. pneumoniae) continue to cause substantial morbidity and mortality globally. Whilst pneumococcal polysaccharide vaccines (PPVs) have the potential to prevent disease and death, the degree of protection afforded against various clinical endpoints and within different populations is uncertain.

OBJECTIVES

To assess the efficacy and effectiveness of PPVs in preventing pneumococcal disease or death in adults. We did not assess adverse events.

SEARCH METHODS

We searched CENTRAL 2012, Issue 6, MEDLINE (January 1966 to June Week 2, 2012) and EMBASE (1974 to June 2012).

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) in adults, provided the study outcome met the definition of the outcome considered in the review. We also considered non-RCTs in adults, where the study assessed PPV effectiveness against culture-confirmed invasive pneumococcal disease (IPD), provided the study controlled for important confounding factors.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial quality of RCTs and three review authors extracted the data. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) using a random-effects model. Two review authors assessed study quality and extracted data for non-RCTs. We calculated ORs and 95% CIs using a random-effects model following the conversion of each study outcome to a log OR and standard error (SE).

MAIN RESULTS

Twenty-five studies met our inclusion criteria (18 RCTs involving 64,852 participants and seven non-RCTs involving 62,294 participants). Meta-analysis of the RCTs found strong evidence of PPV efficacy against IPD with no statistical heterogeneity (OR 0.26, 95% CI 0.14 to 0.45; random-effects model, I(2) statistic = 0%). There was efficacy against all-cause pneumonia in low-income (OR 0.54, 95% CI 0.43 to 0.67, I(2) statistic = 19%) but not high-income countries in either the general population (OR 0.71, 95% CI 0.45 to 1.12, I(2) statistic = 93%) or in adults with chronic illness (OR 0.93, 95% CI 0.73 to 1.19, I(2) statistic = 10%). PPV was not associated with substantial reductions in all-cause mortality (OR 0.90, 95% CI 0.74 to 1.09; random-effects model, I(2) statistic = 69%). Vaccine efficacy against primary outcomes appeared poorer in adults with chronic illness. Non-RCTs provided evidence for protection against IPD in populations for whom the vaccine is currently utilised (OR 0.48, 95% CI 0.37 to 0.61; random-effects model, I(2) statistic = 31%). This review did not consider adverse events as it was outside the scope of the review.

AUTHORS' CONCLUSIONS

This meta-analysis provides evidence supporting the recommendation for PPV to prevent IPD in adults. The evidence from RCTs is less clear with respect to adults with chronic illness. This might be because of lack of effect or lack of power in the studies. The meta-analysis does not provide evidence to support the routine use of PPV to prevent all-cause pneumonia or mortality.

Additive benefits of pneumococcal and influenza vaccines among elderly persons aged 75 years or older in Taiwan--a representative population-based comparative study

OBJECTIVE

It remains unclear whether pneumococcal vaccine provides additional protection to the elderly who have already vaccinated with influenza vaccine. This retrospective cohort study aimed to assess the additive effect of pneumococcal and influenza vaccines on the risk of mortality, hospitalization, and inpatient expenditure in the elderly aged 75 years or older in Taiwan.

METHODS

Data were extracted from the National Health Insurance claims data of a nationally representative elderly sample. To reduce potential selection bias, we employed a propensity score matching method to classify the vaccination status into 3 groups. Multivariable logistic and linear regression models were used to compare the outcomes among different groups.

RESULTS

Each group contained 8142 subjects. The results indicated that an additive effect of receiving both vaccines was associated with a significantly lower all-cause mortality (relative risk [RR]: 0.74; 95% confidence interval [CI]: 0.57-0.96), hospitalization of all diseases including pneumonia, influenza, chronic obstructive pulmonary disease, respiratory diseases, and congestive heart disease (RR: 0.77; 95% CI: 0.67-0.90), and a 13% reduction (95% CI: 0.81-0.94) in inpatient expenditures of all diseases when compared with receiving influenza vaccine alone.

CONCLUSIONS

This study confirmed that vaccination of elderly individuals with pneumococcal vaccine and influenza vaccine concomitantly has substantial beneficial effects.

Viral coinfections in children with invasive pneumococcal disease

BACKGROUND

Respiratory viruses contribute to the seasonal pattern of invasive pneumococcal disease (IPD), but the impact of viral coinfections on the clinical characteristics and outcomes of patients with IPD have not been well defined.

OBJECTIVE

This study was designed to describe and compare the clinical presentations and outcomes of patients with IPD with or without viral coinfections.

DESIGN/METHODS

Retrospective analyses of records of all children treated at Children's Medical Center Dallas (CMCD) for IPD from July 2005 to June 2008. Viral studies included viral direct fluorescent antibody staining and culture. For comparisons, patients were classified in 3 groups: with positive, negative, and no viral studies performed.

RESULTS

A total of 129 patients were admitted to CMCD with IPD during the 3 year study; 57% were male. Ages ranged from 2 months to 18 years (median 25 months) and 48% were <2 years. Viral studies were performed in 82 (63%) patients, and 28 (34%) had positive results. The most common viruses isolated were influenza (7, 25%), rhinoviruses (6, 21%), adenoviruses (6, 21%), and RSV (5, 18%). Peaks of positive viral studies occurred in February and November which coincided with the peak numbers of patients admitted with IPD. Of 6 with adenovirus coinfection, 5 were admitted to Pediatric Intensive Care Unit (PICU). The most common pneumococcal serotypes were 19A (41, 32.5%), 7F (14, 11%), and 23A (13, 10.3%). Pneumonia (42%), bacteremia (22%), and meningitis (17%) were the most common clinical syndromes. There were no differences in duration of fever before admission, maximum temperatures during hospitalization and white blood cell counts, duration of fever and hospitalization between patients with positive and negative viral studies, but there was a trend for patient with positive viral studies to be admitted to PICU more frequently and to have longer PICU stay. Three of the 6 patients who died had documented viral coinfections (2 adenovirus, 1 parainfluenza 3), and all 3 had no underlying conditions. The other 3 patients who died had no viral studies performed. Duration of treatment ranged from 1 to -210 days (median 14), with no differences among the groups.

CONCLUSIONS

Viral coinfections were common in children with IPD. Future prospective studies should include new PCR assays to characterize better the impact of viral coinfections in the occurrence and outcome of IPD.

Encephalitis lethargica and influenza. I. The role of the influenza virus in the influenza pandemic of 1918/1919

An investigation of the characteristics of influenza epidemics in the nineteenth and early twentieth centuries was undertaken, principally in order to analyze the role of the 1918/1919 influenza pandemic in the etiology of encephalitis lethargica. Expectations regarding a future influenza pandemic derive principally from experiences in the 1918 epidemic. It is proposed that this pandemic was atypical with respect to many of its features, and that these have not been appropriately regarded in mapping expectations and responses of a future pandemic. Both a longer historical viewpoint (incorporating knowledge from all major nineteenth and twentieth century epidemics) and closer examination of individual epidemics at the town level is essential for producing an accurate picture of the challenge.

[Why are pediatric empyemas on the increase in Spain?]

There is a widespread perception among Spanish pediatricians that the incidence of empyema has significantly increased in the last few years, even though the objective information available is limited, and there is no specific active epidemiological surveillance system for this condition. In the present article, we review the situation of empyema in Spain, and discuss the main hypotheses put forward in the international literature to explain this increase, as well as the limitations of the sources available. Despite the scarcity of information, we draw the following conclusions: 1) the incidence of pediatric empyema is increasing in Spain, both generally and when caused by pneumococcus in particular; 2) the reason for this increase remains unknown, and to date no firm link has been established between this phenomenon and the heptavalent conjugate pneumococcal vaccine; and 3) this situation justifies the establishment of prospective systems for the surveillance and control of empyema and, once again, highlights the importance of developing active surveillance systems for pneumococcal disease.