Many children aged two to five years have a persistent presence of respiratory viruses in their nasopharynx

Epidemiological and clinical characteristics of children with acute respiratory viral infections in the Philippines: a prospective cohort study

OBJECTIVES

Viral acute respiratory infection (ARI) remains a major global health problem, especially among children in low- and middle-income countries. The study was conducted to reveal aetiological significance of respiratory viruses among both non-hospitalized and hospitalized children.

METHODS

A cohort study of children with ARI at the household, primary healthcare facility, and hospital levels was conducted alongside a hospital-based study including non-cohort children from 2014 to 2016 in the Philippines. The ARI cases were recorded at households and healthcare facilities, and a clinical investigation was performed. Nasopharyngeal swabs were collected from the symptomatic children and tested for respiratory viruses via polymerase chain reaction. Then, the association between healthcare facility utilization and viral detection was investigated.

RESULTS

Overall, 18,514 ARI cases were enrolled in the cohort study, and samples were collected from 4735 of these cases. The hospital-based study detected 648 ARI cases, all of which were sampled. Rhinovirus (22.2%; 1052/4735) was most frequently detected followed by respiratory syncytial virus (12.0%; 566/4735). Enterovirus (adjusted odds ratio, 1.8; 95% confidence interval, 1.1-2.8), human metapneumovirus (2.1, 1.4-3.2), rhinovirus (2.1, 1.8-2.6), and respiratory syncytial virus (1.6, 1.2-1.9) were significantly more prevalent in the ARI cases at healthcare facilities than in those in households. Of all ARI cases, 0.6% required hospitalization while 1.8% were hospitalized among the respiratory syncytial virus-positive cases (3.8, 3.0-4.9).

CONCLUSIONS

We determined the prevalence of respiratory viruses among children with ARIs at the household, primary healthcare facility, and hospital levels and the association with clinical characteristics. In particular, we discovered a significant disease burden and impact of respiratory syncytial virus infections as well as a considerable aetiological implication of rhinovirus infections.

Time to Say Goodbye to Bronchiolitis, Viral Wheeze, Reactive Airways Disease, Wheeze Bronchitis and All That

The diagnosis and management of infants and children with a significant viral lower respiratory tract illness remains the subject of much debate and little progress. Over the decades various terms for such illnesses have been in and fallen out of fashion or have evolved to mean different things to different clinicians. Terms such as "bronchiolitis," "reactive airways disease," "viral wheeze," and many more are used to describe the same condition and the same term is frequently used to describe illnesses caused by completely different dominant pathologies. This lack of clarity is due, in large part, to a failure to understand the basic underlying inflammatory and associated processes and, in part, due to the lack of a simple test to identify a condition such as asthma. Moreover, there is a lack of insight into the fact that the same pathology can produce different clinical signs at different ages. The consequence is that terminology and fashions in treatment have tended to go around in circles. As was noted almost 60 years ago, amongst pre-school children with a viral LRTI and airways obstruction there are those with a "viral bronchitis" and those with asthma. In the former group, a neutrophil dominated inflammation response is responsible for the airways' obstruction whilst amongst asthmatics much of the obstruction is attributable to bronchoconstriction. The airways obstruction in the former group is predominantly caused by airways secretions and to some extent mucosal oedema (a "snotty lung"). These patients benefit from good supportive care including supplemental oxygen if required (though those with a pre-existing bacterial bronchitis will also benefit from antibiotics). For those with a viral exacerbation of asthma, characterized by bronchoconstriction combined with impaired b-agonist responsiveness, standard management of an exacerbation of asthma (including the use of steroids to re-establish bronchodilator responsiveness) represents optimal treatment. The difficulty is identifying which group a particular patient falls into. A proposed simplified approach to the nomenclature used to categorize virus associated LRTIs is presented based on an understanding of the underlying pathological processes and how these contribute to the physical signs.

Association Between Preceding Viral Respiratory Infection and Subsequent Respiratory Illnesses Among Children: A Prospective Cohort Study in the Philippines

Background

Acute respiratory infection (ARI) is of great concern in public health. It remains unclear whether viral infections can affect the host’s susceptibility to subsequent ARIs.

Methods

A prospective cohort study on ARIs of children below 5 years old was conducted in the Philippines from 2014 to 2016. The respiratory symptoms were recorded daily, and nasopharyngeal swabs were collected at both household and health facilities. The specimens were tested for respiratory viruses. We then determined whether viral etiology was associated with the severity of the present ARI and whether previous viral infections was associated with subsequent ARIs.

Results

A total of 3851 children and 16337 ARI episodes were enrolled and recorded, respectively. Samples were collected from 24% of all ARI episodes; collection rate at the healthcare facilities was 95%. Enterovirus D68, rhinovirus species C, and respiratory syncytial virus were significantly associated with severe ARIs. The risk for subsequent ARIs was significantly enhanced after infections with adenovirus, influenza A virus, parainfluenza virus type 4, and rhinovirus species C.

Conclusions

This study revealed that viral etiology plays a significant role in the severity of the present ARI and that viral infection affects the host’s susceptibility to subsequent ARIs.

Evidence for respiratory viruses interactions in asymptomatic preschool-aged children

Aim

To prospectively evaluate interferences between viruses of the upper respiratory tract in asymptomatic preschool children.

Methods

Nasal-pharyngeal swabs from 233 preschool aged children were prospectively collected over four consecutive time periods, during one school year. The samples were tested using a RT-PCR DNA/RNA microarray system for nine respiratory viruses.

Results

Respiratory syncytial virus (RSV) was a predictor of the presence of influenza virus (INFL) (OR: 9.12, CI: 1.52–54.75, p = 0.016), and similarly, INFL predicted the presence of RSV (OR: 4.01, CI: 1.14–14.16, p = 0.030). Also, rhinovirus (RV) was a predictor of adenovirus (ADV) presence (OR: 3.66, CI: 1.10–12.14, p = 0.034), and similarly, ADV predicted the presence of RV (OR: 4.05, CI: 1.02–16.05, p = 0.046). No other significant associations between viruses were observed.

Conclusion

Our results indicate that respiratory viruses found in carrier stage in asymptomatic children may interact with other viruses and even facilitate their settling in the upper respiratory tract. The pathophysiological role of these interactions is not yet clear.

Rhinovirus-specific antibody responses in preschool children with acute wheeze reflect severity of respiratory symptoms

BACKGROUND

Some children with rhinovirus (RV) infections wheeze, but it is unknown whether this is due to more virulent strains of virus or differences in host immune responses. The aim of this study was to investigate the RV species-specific antibody responses measured at a follow-up visit in preschool children in relation to reported time with respiratory symptoms and the presence of different RV species during an acute episode of wheeze.

METHOD

Nasopharyngeal swabs and blood samples were taken among 120 preschool children (<4 years of age) at an acute episode of wheeze and at a follow-up visit (median 11 weeks later). Nested PCR was used to detect different RV strains, and serum levels of IgG₁ against purified recombinant VP1 proteins from representatives of the three RV species (RV-A, RV-B, and RV-C) were measured by ELISA.

RESULTS

Rhinovirus was detected in 74% (n = 80/108) of the children at the acute visit, and RV-C was the most common subtype (n = 59/80, 74%). An increase in RV-specific IgG₁ was seen in 61% (n = 73) of the children at follow-up, most frequently against RV-A (n = 61/73, 86%) irrespective of the RV strains detected by PCR. Increases in RV-specific IgG₁ against RV-A or against RV-A and RV-C were significantly associated with more respiratory symptoms (p = 0.03, p = 0.007).

CONCLUSION

Antibody response to recombinant RV VP1 proteins was associated with longer time with respiratory symptoms.

Is the role of rhinoviruses as causative agents of pediatric community-acquired pneumonia over-estimated?

The role that rhinoviruses, enteroviruses, parainfluenza viruses, coronaviruses and human bocavirus play in pediatric pneumonia is insufficiently studied. We used polymerase chain reaction (PCR) to study 9 virus groups, including 16 different viruses or viral strains, in 56 ambulatory children with radiologically confirmed community-acquired pneumonia (CAP). The same tests were carried out on 474 apparently healthy control children of the same age and sex. The mean age of children with CAP was 6.5 years (SD 4.2). Respiratory syncytial virus (RSV) was found in 19.6 % of 56 cases and in 2.1 % of 474 controls. Adenoviruses were present in 12.5 % of cases (0.2 % controls) and metapneumovirus and influenza A virus each in 10.7 % of cases (0.2 % controls). Interestingly, rhinoviruses were less common in cases (10.7 %) than in controls (22.4 %): odds ratio 0.36 (95%CI) 0.15-0.87) in conditional logistic regression including 56 cases and 280 controls matched for age, sex and sampling month. The prevalence of parainfluenza viruses, enteroviruses, coronaviruses and human bocavirus were similar in both groups.

CONCLUSION

We conclude that the role of rhinoviruses as an etiology of pediatric CAP has been over-estimated, mainly due to the non-controlled designs of previous studies. What is Known: • In non-controlled studies, rhinovirus detection has been common, next to respiratory syncytial virus, in children with viral community-acquired pneumonia (CAP). • Enteroviruses, coronaviruses and the human bocavirus have been found less frequently. What is New: • In this controlled study, rhinoviruses were detected more often in healthy controls than in children with CAP, and enteroviruses, coronaviruses and human bocavirus were detected equally often in cases and controls. • We conclude that previous studies have over-estimated the role of rhinoviruses in the etiology of CAP in children.