To evaluate retrospectively human rhinovirus (HRV) infections in children up to 5 years old and factors involved in disease severity.
Nasopharyngeal aspirates from 434 children presenting a broad range of respiratory infection symptoms and severity degrees were tested for presence of HRV and 8 other respiratory viruses. Presence of host risk factors was also assessed.
HRV was detected in 181 (41.7%) samples, in 107 of them as the only agent and in 74 as coinfections, mostly with respiratory syncytial virus (RSV; 43.2%). Moderate to severe symptoms were observed in 28.9% (31/107) single infections and in 51.3% (38/74) coinfections (P = .004). Multivariate analyses showed association of coinfections with lower respiratory tract symptoms and some parameters of disease severity, such as hospitalization. In coinfections, RSV was the most important virus associated with severe disease. Prematurity, cardiomyopathies, and noninfectious respiratory diseases were comorbidities that also were associated with disease severity (P = .007).
Our study showed that HRV was a common pathogen of respiratory disease in children and was also involved in severe cases, causing symptoms of the lower respiratory tract. Severe disease in HRV infections were caused mainly by presence of RSV in coinfections, prematurity, congenital heart disease, and noninfectious respiratory disease.
Comments
Is human rhinovirus a real crucial pathogen in severe lower respiratory tract infections in children?
Evaluating children up to 5 years old, Costa et al. [1] reported that HRV is a common pathogen of respiratory disease, being involved in severe lower respiratory tract infections (LRTI). Nevertheless, the majority of HRV single infections caused only mild symptoms whereas severe forms of acute respiratory infections (ARIs) were more frequently due to HRV+RSV coinfections, especially in younger children. This finding is not surprising since it has been already reported that almost all children have acquired a RSV infection in the first 2 years of life and that RSV is also the major cause of hospitalization/mortality in children up to 1 year. Costa et al. [1] also showed that the frequency of moderate-to-severe symptoms were comparable between HRV+RSV coinfections versus RSV single infections, suggesting that more severe conditions seem to be mainly due to RSV rather than to HRV infection, as already demonstrated by Bosis et al. [2] Analyzing infants (<1 years) hospitalized because of acute episode of wheezing, the authors [2] reported no single infection hospitalization due to rhinovirus which was only detected in infants with RSV coinfections. Moreover, Costa el al. [1] concluded that severe disease in HRV infections were caused in concurrence to other risk factors that have been long recognized to be the risk factors for RSV-induced hospitalization. [3] More than ten years ago, we designed a multicenter study to evaluate which of the possible risk factors might be associated with ARIs severity in Italy [4] and found that over 40% were infected by RSV (RSV+). A high proportion of subjects had low birth weight and low gestational age and among children hospitalized for bronchiolitis, a higher prevalence of RSV+ was found in patients born at <35 weeks of gestational age (p<0.04). Exposure to passive tobacco smoke and birth order increased the likelihood of hospitalization or were associated with severe diseases. Some of these risk factors are found continuously throughout the scientific literature. [3] The paper is interesting but it seems unlikely that the findings reported by Costa et al. [1] can actually help the physicians to better manage children who are at higher risk of more severe respiratory disease with HRV. Since a vaccine able to prevent HRV infections is not yet available, the prevention relies only on standard hygiene measures for aerosol- transmitted infections (careful hand hygiene and environmental prophylaxis) that are useful particularly during the epidemic season and in preventing nosocomial infections expecially for high-risk patients. The prevention of RSV disease relies not only on behavioral/environmental infection control but also on providing palivizumab prophylaxis in selected infants with high risk of hospitalization and/or death. [5] Moreover, rapid bedside identification tests on which to base hospital cohorting of high-risk patients are possible for RSV but not as easy as for HRV infections. This study further confirms the role of RSV in determining severe infections (especially when associated to other viruses) rather than to demonstrate a crucial role of HRV in causing severe symptoms of LRTI.
References
1. Costa LF, Queiroz DA, Lopes da Silveira H, Bernardino Neto M, de Paula NT, Oliveira TF, Tolardo AL, Yokosawa J. Human rhinovirus and disease severity in children. Pediatrics. 2014;133:e312-21.
2. Bosis S, Esposito S, Niesters HG, Zuccotti GV, Marseglia G, Lanari M, Zuin G, Pelucchi C, Osterhaus AD, Principi N. Role of respiratory pathogens in infants hospitalized for a first episode of wheezing and their impact on recurrences. Clin Microbiol Infect. 2008;14:677-684.
3. Simoes EAF. Environmental and demographic risk factors for respiratory syncytial virus lower respiratory tract disease J Pediatr. 2003;143:S118-S126.
4. Lanari M, Giovannini M, Giuffre L, Marini A, Rondini G, Rossi GA, Merolla R, Zuccotti GV, Salvioli GP. Prevalence of respiratory syncytial virus infection in Italian infants hospitalized for acute lower respiratory tract infections, and association between respiratory syncytial virus infection risk factors and disease severity. Ped Pulmonol. 2002; 33:458-465.
5. The IMpact-RSV Study Group Palivizumab, a humanized respiratory syncytial virus monoclonal antibody, reduces hospitalization from respiratory syncytial virus infection in high-risk infants. Pediatrics. 1998;102:531-537.
Conflict of Interest:
The authors serve as consultant for AbbVie S.r.L.