Respiratory Syncytial Virus-associated hospitalization in premature infants who did not receive palivizumab prophylaxis in Italy: a retrospective analysis from the Osservatorio Study

Risk Factors for Respiratory Syncytial Virus Infections in Moderate/Late Premature Infants in Turkey: A Prospective Multicenter Epidemiological Study

OBJECTIVE

Respiratory syncytial virus (RSV) is one of the most prevalent causes of lower respiratory tract infection (LRTI). The primary objective of this study is to provide the risk modelling of confirmed RSV infection in children who were born preterm at 29 to 35 weeks of gestational age and presented with LRTI.

STUDY DESIGN

This prospective, multicenter study was performed between October 2015 and March 2017. Premature infants born with gestational age between 29 and 35 weeks that were ≤2 years of age at the beginning of the RSV season and admitted to the hospital with clinical findings of LRTI during the season were included. RSV-positive and -negative infants were compared in terms of demographic features, risk factors, and requirement of hospitalization.

RESULTS

RSV positive group was lower than RSV negative group and ratio of ≤3 months age at admission was significant higher in RSV (+) group. RSV-positive infants were found to be significantly born during or 3 months prior to RSV season. The rate and duration of hospitalization and need for mechanical ventilation were significantly higher in RSV positive infants. The rate and duration of hospitalization in RSV positive patients was related to the chronological age.

CONCLUSION

This study showed that preterm infants with RSV-associated LRTI significantly needed more hospitalization, intensive care admission, and mechanical ventilation. In addition need of hospitalization and duration of hospitalization were significant higher in ≤3 months of age. Therefore, we suggest the importance of palivizumab prophylaxis in infants ≤ 3 months chronological age, especially during the RSV season.

Passive Immunoprophylaxis against Respiratory Syncytial Virus in Children: Where Are We Now?

Respiratory syncytial virus (RSV) represents the main cause of acute respiratory tract infections in children worldwide and is the leading cause of hospitalization in infants. RSV infection is a self-limiting condition and does not require antibiotics. However hospitalized infants with clinical bronchiolitis often receive antibiotics for fear of bacteria coinfection, especially when chest radiography is performed due to similar radiographic appearance of infiltrate and atelectasis. This may lead to unnecessary antibiotic prescription, additional cost, and increased risk of development of resistance. Despite the considerable burden of RSV bronchiolitis, to date, only symptomatic treatment is available, and there are no commercially available vaccines. The only licensed passive immunoprophylaxis is palivizumab. The high cost of this monoclonal antibody (mAb) has led to limiting its prescription only for high-risk children: infants with chronic lung disease, congenital heart disease, neuromuscular disorders, immunodeficiencies, and extreme preterm birth. Nevertheless, it has been shown that the majority of hospitalized RSV-infected children do not fully meet the criteria for immune prophylaxis. While waiting for an effective vaccine, passive immune prophylaxis in children is mandatory. There are a growing number of RSV passive immunization candidates under development intended for RSV prevention in all infants. In this review, we describe the state-of-the-art of palivizumab's usage and summarize the clinical and preclinical trials regarding the development of mAbs with a better cost-effectiveness ratio.

Risk of childhood wheeze and asthma after respiratory syncytial virus infection in full-term infants

BACKGROUND

Most studies addressing the association between RSV and recurrent wheezing (RW) and asthma have been conducted in patients at risk for lung morbidity. Data in full-term infants are limited.

METHODS

The risk of RW/asthma during the first 5 years of life in full-term infants hospitalized with RSV during the first year (Y) of life was estimated using 2010-16 data from three claims databases in USA (Truven MarketScan Commercial Claims and Encounters Database [CCAE], Truven Health MarketScan Multi-State Medicaid [MDCD], and Optum Clinformatics Extended Data Mart-Socio-Economic Status [SES]). Full-term infants with and without RSV infection and ≥ 2 years of continuous health plan enrollment from birth were included. Incidence rates of RW/asthma, cumulative incidence, adjusted incidence rate ratios (aIRR), and odds ratios (aOR) were calculated.

RESULTS

During the 16-year study, 38,494 (CCAE), 62 846 (MDCD), and 23 099 (SES) matched infant pairs were included in each cohort. In the CCAE database, RW/asthma incidence/1000 patient-years (69.7 vs 28.7, aIRR: 2.4 [2.3-2.5]); cumulative incidence (17.6%-25.2% vs 5.0%-11.4%); and aOR (Y2: 4.1 [3.9-4.4]; Y3: 3.2 [3.0-3.3]; Y4: 2.9 [2.7-3.1]; Y5: 2.6 [2.5-2.9]) were higher in the RSV vs. non-RSV cohort. Results in the SES insured population were comparable, while cumulative incidence and aIRR were higher in the Medicaid population (MDCD).

CONCLUSION

Although there are limitations in this study, including possible coding errors and missing covariates, we showed that full-term infants with severe RSV infection during the first year of life, spanning several respiratory seasons and a geographically diverse population, are at significant risk of RW/asthma during childhood.

Impact of the 2014 American Academy of Pediatrics recommendation and of the resulting limited financial coverage by the Italian Medicines Agency for palivizumab prophylaxis on the RSV-associated hospitalizations in preterm infants during the 2016-2017 epidemic season: a systematic review of seven Italian reports

BACKGROUND

The only pharmacologic prophylaxis against respiratory syncytial virus (RSV) infection in preterm infants is the humanized monoclonal antibody palivizumab. After the 2014 modification of the American Academy of Pediatrics (AAP) recommendations, the Italian Medicines Agency (AIFA) limited the financial coverage for palivizumab prescriptions to otherwise healthy preterm infants with < 29 weeks of gestational age (wGA) aged < 12 months at the beginning of the 2016-2017 RSV season. However, due to the effect on disease severity and hospitalizations following this limitation, shown by several Italian clinical studies, in November 2017 AIFA reinstated the financial coverage for these infants. In this systematic review, we critically summarize the data that show the importance of palivizumab prophylaxis.

METHODS

Data from six Italian pediatric institutes and the Italian Network of Pediatric Intensive Care Units (TIPNet) were retrieved from the literature and considered. The epidemiologic information for infants 29-36 wGA, aged < 12 months and admitted for viral-induced acute lower respiratory tract infection were retrospectively reviewed. RSV-associated hospitalizations were compared between the season with running limitation, i.e. 2016-2017, versus 2 seasons before (2014-2015 and 2015-2016) and one season after (2017-2018) the AIFA limitation.

RESULTS

During the 2016-2017 RSV epidemic season, when the AIFA limited the financial coverage of palivizumab prophylaxis based on the 2014 AAP recommendation, the study reports on a higher incidences of RSV bronchiolitis and greater respiratory function impairment. During this season, we also found an increase in hospitalizations and admissions to the Pediatric Intensive Care Units and longer hospital stays, incurring higher healthcare costs. During the 2016-2017 epidemic season, an overall increase in the number of RSV bronchiolitis cases was also observed in infants born full term, suggesting that the decreased prophylaxis in preterm infants may have caused a wider infection diffusion in groups of infants not considered to be at risk.

CONCLUSIONS

The Italian results support the use of palivizumab prophylaxis for otherwise healthy preterm (29-36 wGA) infants aged < 6 months at the beginning of the RSV season.

Respiratory Syncityal Virus A and B: three bronchiolitis seasons in a third level hospital in Italy

Background

Respiratory syncytial virus (RSV) is the main cause of hospitalization for bronchiolitis among infants. RSV is classified into two subtypes, A and B, whose predominance alternates during different epidemic seasons. The clinical impact of viral factors is controversial and many evidences suggest a critical role for the immune host response. Premature children are at the highest risk for severe RSV infection. The main aim of this study is to identify the different RSV subtypes circulating in the last three epidemic seasons and to evaluate whether any of them was associated with poor prognosis in term and preterm infants.

Methods

We performed a retrospective analysis of medical records for all patients aged less than one year which were hospitalized during the winter season between November 2015 and April 2018 with clinical diagnosis of bronchiolitis and nasopharyngeal aspirates positive for RSV.

Results

We enrolled 422 children, of which 50 were born preterm. During the analysis period, we observed a significant increase in the rates of oxygen supplementation and admission to intensive care unit. The evidence shows an alternating pattern in the prevalence of RSV subtypes among term born; in each epidemic season, the prevalent serotype is the cause of the majority of the cases requiring intensive care. Conversely, RSV-A is always prevalent in preterm children and caused most of the cases requiring intensive care.

Conclusions

During the 3 seasons analyzed, we observed an alternating prevalence of RSV A and B. While there are no differences in severity between RSV A and B in term population, RSV-A is prevalent and causes most of the severe cases in the premature group. Furthermore, an increase in RSV-related oxygen therapy and PICU admission has been documented not only in the premature population. Considering the absence of appropriate therapeutic strategies, our work emphasizes the importance of implementing prophylaxis measures against RSV and highlights the urgent need to gain knowledge about immune response to the virus, also in premature children.

Electronic supplementary material

The online version of this article (10.1186/s13052-019-0704-0) contains supplementary material, which is available to authorized users.

Human respiratory syncytial virus and hospitalization in young children in Italy

BACKGROUND

Human respiratory syncytial virus (hRSV) is ubiquitous and causes respiratory diseases in both children and adults. Worldwide, hRSV pneumonia is the second cause of postnatal infant death after malaria. Given the high impact in terms of morbidity, mortality and costs, especially in the pediatric population, hRSV is recognized as a global health problem and the WHO, in view of the availability of new vaccines, has urged an active surveillance program of virus-related infections. The aim of this study has been to evaluate the impact of hRSV infections in the Italian population, particularly the pediatric one, in terms of hospitalizations.

METHODS

In the period 2001-2014, Hospital Discharge Records (HDRs) with the following diagnosis codes included in the primary diagnosis were evaluated: 466.11 (hRSV bronchiolitis), 480.1 (hRSV pneumonia) and 796 (hRSV). HDRs were supplied by the National Archive of HDRs data, Ministry of Health.

RESULTS

During the period 2001-2014, 57,656 hospital admissions due to hRSV pathologies were performed. Most hospitalizations (88.8%) involved patients with less than 1 year of age. Considering only primary diagnosis, 93% of the admissions were due to bronchiolitis, 5% to pneumonia and 2% to not otherwise specified hRSV infections. In the period 2001-2014, the hospitalization rate in 0-2 years old children, was equal to 224.8, 9.6 and 4.6/100,000 for hRSV bronchiolitis, hRSV pneumonia and not otherwise specified hRSV infection, respectively.

CONCLUSIONS

This study confirms the high impact of hRSV on the pediatric population in the age class 0-4 years, with a peak in the first 12 months of life. Most hospitalizations were urgent, although the duration of the hospital stay was for the most part less than a week, with ordinary discharge at home. Pending the conclusion of ongoing clinical trials on different hRSV vaccine types, it is extremely important to have updated data on the impact of hRSV-related pathologies in the various age groups.

The impact of the recent AAP changes in palivizumab authorization on RSV-induced bronchiolitis severity and incidence

Following the most recent modification by the American Academy of Pediatrics, based on American studies on RSV epidemiology, the Italian Drug Agency (AIFA) decided to limit the total financial coverage of the palivizumab prescription by the National Health Service only to the < 29 wGA group and age ≤ 12 months at the beginning of the RSV epidemic season. However, the vulnerability of otherwise healthy premature infants ≥ 29 wGA has been demonstrated in Italian analyses. We retrospectively reviewed records from children ≤ 1 years of age admitted for RSV-induced ALRI at the Gaslini Hospital, over three consecutive RSV epidemic seasons (RES) (2014-2017). We found that the prescription limitation on RSV immunoprophylaxis in preterms was associated in the 2016-2017 RES with: a) a high proportion of admission for the < 36 wGA infants, the great majority born at 33- < 36 wGA and a chronological age of < 6 months; b) a high proportion of preterms treated with high flow nasal cannula ventilation. These results strongly point to a need to reevaluate the role of palivizumab prophylaxis in the >= 29 wGA subpopulation when specific risk factors are present.

Efficacy of palivizumab prophylaxis on the frequency of RSV-associated lower respiratory tract infections in preterm infants: determination of the ideal target population for prophylaxis

Respiratory syncytial virus (RSV) prophylaxis in high-risk infants is an effective intervention for the prevention of severe disease. The aim of this study was to determine the ideal target preterm population that might benefit from palivizumab prophylaxis by establishing the main risk factors for acute RSV-related infections. Former premature infants born with a gestational age ≤37 weeks and ≤1 year of age at the beginning of the RSV season and admitted with respiratory infection were included. RSV status was evaluated by RSV strip test in all infants. RSV-positive and -negative infants were compared in terms of demographic features, risk factors, requirement of hospitalisation and palivizumab administration. A total of 202 preterm infants under 1 year of age were enrolled. The RSV test was positive in 34 (16.8%) infants. Maternal age was significantly lower in RSV-positive infants compared with RSV-negative infants (p = 0.03). RSV-positive infants were found to be significantly discharged during the RSV season (p = 0.03). RSV-positive infants required significantly higher rates of hospitalisation and need for mechanical ventilation. Of the RSV-positive infants, 28 (82%) had a gestational age ≥29 weeks. Seventeen (77%) RSV-positive infants that required hospitalisation were ≥29 weeks of gestation. All infants with a gestational age ≥29 weeks and without palivizumab prophylaxis developed RSV infection. Palivizumab prophylaxis should be implemented into guidelines to cover preterm infants with a gestational age >29 weeks. Palivizumab prophylaxis should also be considered in high-risk infants ≤6 months of age during the RSV season.

Defining the Risk and Associated Morbidity and Mortality of Severe Respiratory Syncytial Virus Infection Among Preterm Infants Without Chronic Lung Disease or Congenital Heart Disease

INTRODUCTION

The REGAL (RSV Evidence-a Geographical Archive of the Literature) series provide a comprehensive review of the published evidence in the field of respiratory syncytial virus (RSV) in Western countries over the last 20 years. This second publication covers the risk and burden of RSV infection in preterm infants born at <37 weeks' gestational age (wGA) without chronic lung disease or congenital heart disease.

METHODS

A systematic review was undertaken for articles published between January 1, 1995 and December 31, 2015. Studies reporting data for hospital visits/admissions for RSV infection among preterm infants as well as studies reporting RSV-associated morbidity, mortality, and risk factors were included. Study quality and strength of evidence (SOE) were graded using recognized criteria.

RESULTS

2469 studies were identified of which 85 were included. Preterm infants, particularly those born at lower wGA, tended to have higher RSV hospitalization (RSVH) rates compared with otherwise healthy term infants (high SOE). RSVH rates ranged from ~5 per 1000 children to >100 per 1000 children with the highest rates shown in the lowest gestational age infants (high SOE). Independent risk factors associated with RSVH include: proximity of birth to the RSV season, living with school-age siblings, smoking of mother during pregnancy or infant exposure to environmental smoking, reduced breast feeding, male sex, and familial atopy (asthma) (high SOE). Predictive models can identify 32/33-35 wGA infants at risk of RSVH (high SOE).

CONCLUSION

RSV infection remains a major burden on Western healthcare systems and is associated with significant morbidity. Further studies focusing on the prevalence and burden of RSV in different gestational age cohorts, the changing risk of RSVH during the first year of life, and on RSV-related mortality in preterm infants are needed to determine the true burden of disease.

FUNDING

AbbVie.