Palivizumab use during respiratory syncytial virus outbreak in the neonatal intensive care unit

Multiple Respiratory Syncytial Virus Introductions Into a Neonatal Intensive Care Unit

BACKGROUND

Outbreaks of respiratory syncytial virus (RSV) in neonatal intensive care units (NICUs) are of concern because of the risk of severe disease in young infants. We describe an outbreak of RSV in a NICU and use whole genome sequencing (WGS) to better understand the relatedness of viruses among patients.

METHODS

An investigation was conducted to identify patients and describe their clinical course. Infection control measures were implemented to prevent further spread. Respiratory specimens from outbreak-related patients and the community were tested using WGS. Phylogenetic trees were constructed to understand relatedness of the viruses.

RESULTS

Seven patients developed respiratory symptoms within an 11-day span in December 2017 and were diagnosed with RSV; 6 patients (86%) were preterm and 1 had chronic lung disease. Three patients required additional respiratory support after symptom onset, and none died. Six of 7 patients were part of the same cluster based on > 99.99% nucleotide agreement with each other and 3 unique single-nucleotide polymorphisms were identified in viruses sequenced from those patients. The seventh patient was admitted from the community with respiratory symptoms and had a genetically distinct virus that was not related to the other 6. Implementation of enhanced infection control measures likely limited the spread.

CONCLUSIONS

Using WGS, we found 2 distinct introductions of RSV into a NICU, highlighting the risk of healthcare-associated infections during RSV season. Early recognition and infection control measures likely limited spread, emphasizing the importance of considering RSV in the differential diagnosis of respiratory infections in healthcare settings.

First report of two consecutive respiratory syncytial virus outbreaks by the novel genotypes ON-1 and NA-2 in a neonatal intensive care unit

OBJECTIVE

Respiratory syncytial virus is a pathogen frequently involved in nosocomial outbreaks. Although several studies have reported nosocomial outbreaks in neonatal intensive care units, molecular epidemiology data are scarce. Here, the authors describe two consecutive respiratory syncytial virus outbreaks caused by genotypes ON-1 and NA-2 in a neonatal intensive care unit in São Paulo, Brazil.

METHODS

A prospective search for respiratory syncytial virus was performed after diagnosing the index case and four other symptomatic newborns in the neonatal intensive care unit. Nasopharyngeal aspirate samples of all patients in the neonatal intensive care unit were tested for 17 respiratory viruses using real-time reverse transcriptase polymerase chain reaction. Genotyping was performed using nucleotide sequencing.

RESULTS

From May to August 2013, two different outbreaks were detected in the neonatal intensive care unit. A total of 20 infants were infected with respiratory syncytial virus-A (ten and 14 with ON-1 and NA-2 genotypes, respectively). The mean age of the infants was 10 days, mean birth weight was 1,961g, and the mean gestational age was 33 weeks. Risk factors (heart disease, lung disease, and prematurity) were present in 80% and 85.7% of infants in the ON-1 and NA-2 groups, respectively. In total, 45.8% of infants were asymptomatic and 20.8% required mechanical ventilation. Coinfections were not detected during the outbreaks.

CONCLUSIONS

Infants in a neonatal intensive care unit who develop abrupt respiratory symptoms should be tested for respiratory viruses, especially respiratory syncytial virus. Even in the absence of severe symptoms, respiratory syncytial virus detection can prevent nosocomial transmission through infection control measures. A better understanding of respiratory syncytial virus molecular epidemiology is essential for developing new vaccines and antiviral drugs against respiratory syncytial virus.

First report of two consecutive respiratory syncytial virus outbreaks by the novel genotypes ON‐1 and NA‐2 in a neonatal intensive care unit

Objetivo

O vírus sincicial respiratório é um patógeno frequentemente envolvido em surtos nosocomiais. Embora vários estudos tenham relatado tais surtos em unidades de terapia intensiva neonatal, os dados epidemiológicos moleculares são escassos. Neste artigo, descrevemos dois surtos consecutivos de vírus sincicial respiratório causados pelos genótipos ON‐1 e NA‐2 em uma unidade de terapia intensiva neonatal em São Paulo, Brasil.

Métodos

Uma busca prospectiva por vírus sincicial respiratório foi realizada após o diagnóstico do caso índice e outros quatro recém‐nascidos sintomáticos na unidade de terapia intensiva neonatal. Amostras de aspirado nasofaríngeo de todos os pacientes da unidade de terapia intensiva neonatal foram testadas para 17 vírus respiratórios com reação em cadeia da polimerase via transcriptase reversa em tempo real. A genotipagem realizada utilizando sequenciamento de nucleotídeos.

Resultados

De maio a agosto de 2013, foram detectados dois surtos diferentes na unidade de terapia intensiva neonatal. Vinte e quatro crianças foram infectadas com vírus sincicial respiratório‐A (10 e 14 com os genótipos ON‐1 e NA‐2, respectivamente). A média da idade dos lactentes era de 10 dias, o peso médio ao nascer foi de 1961 g e a idade gestacional média de 33 semanas. Fatores de risco (doença cardíaca, doença pulmonar e prematuridade) estavam presentes em 80% e 85,7% dos bebês nos grupos ON‐1 e NA‐2, respectivamente. No total, 45,8% dos lactentes eram assintomáticos e 20,8% necessitaram de ventilação mecânica. Não foram detectadas coinfecções durante os surtos.

Conclusões

Bebês em unidade de terapia intensiva neonatal que desenvolvem sintomas respiratórios abruptos devem ser testados para vírus respiratórios, especialmente o vírus sincicial respiratório. Mesmo na ausência de sintomas graves, a detecção de vírus sincicial respiratório pode prevenir a transmissão nosocomial através de medidas de controle de infecção. Um melhor entendimento da epidemiologia molecular do vírus sincicial respiratório é essencial para o desenvolvimento de novas vacinas e drogas antivirais contra o vírus sincicial respiratório.

Risk of nosocomial respiratory syncytial virus infection and effectiveness of control measures to prevent transmission events: a systematic review

Respiratory syncytial virus (RSV) causes a significant public health burden, and outbreaks among vulnerable patients in hospital settings are of particular concern. We reviewed published and unpublished literature from hospital settings to assess: (i) nosocomial RSV transmission risk (attack rate) during outbreaks, (ii) effectiveness of infection control measures. We searched the following databases: MEDLINE, EMBASE, CINAHL, Cochrane Library, together with key websites, journals and grey literature, to end of 2012. Risk of bias was assessed using the Cochrane risk of bias tool or Newcastle–Ottawa scale. A narrative synthesis was conducted. Forty studies were included (19 addressing research question one, 21 addressing question two). RSV transmission risk varied by hospital setting; 6–56% (median: 28·5%) in neonatal/paediatric settings (n = 14), 6–12% (median: 7%) in adult haematology and transplant units (n = 3), and 30–32% in other adult settings (n = 2). For question two, most studies (n = 13) employed multi‐component interventions (e.g. cohort nursing, personal protective equipment (PPE), isolation), and these were largely reported to be effective in reducing nosocomial transmission. Four studies examined staff PPE; eye protection appeared more effective than gowns and masks. One study reported on RSV prophylaxis for patients (RSV‐Ig/palivizumab); there was no statistical evidence of effectiveness although the sample size was small. Overall, risk of bias for included studies tended to be high. We conclude that RSV transmission risk varies widely during hospital outbreaks. Although multi‐component control strategies appear broadly successful, further research is required to disaggregate the effectiveness of individual components including the potential role of palivizumab prophylaxis.

Outcome of the Respiratory Syncytial Virus related acute lower respiratory tract infection among hospitalized newborns: a prospective multicenter study

AIM

To determine the incidence and outcomes of respiratory syncytial virus (RSV)-related acute lower respiratory tract infection (ALRI) including morbidity, nosocomial infection and mortality among newborn infants who were admitted to the neonatal intensive care units (NICUs).

METHODS

A multicenter, prospective study was conducted in newborns who were hospitalized with community acquired or nosocomial RSV infection in 44 NICUs throughout Turkey. Newborns with ALRI were screened for RSV infection by Respi-Strip®-test. Main outcome measures were the incidence of RSV-associated admissions in the NICUs and morbidity, mortality and epidemics results related to these admissions.

FINDINGS

The incidence of RSV infection was 1.24% (n: 250) and RSV infection constituted 19.6% of all ALRI hospitalizations, 226 newborns (90.4%) had community-acquired whereas 24 (9.6%) patients had nosocomial RSV infection in the NICUs. Of the 250 newborns, 171 (68.4%) were full-term infants, 183 (73.2%) had a BW >2500 g. RSV-related mortality rate was 1.2%. Four NICUs reported seven outbreaks on different months, which could be eliminated by palivizumab prophylaxis in one NICU.

CONCLUSION

RSV-associated ALRI both in preterm and term infants accounts an important percent of hospitalizations in the season, and may threat other high-risk patients in the NICU.

Maternal antibodies by passive immunization with formalin inactivated respiratory syncytial virus confer protection without vaccine-enhanced disease

Maternal immunization of mice with formalin inactivated respiratory syncytial virus (FI-RSV) resulted in the passive transfer of RSV antibodies but not cellular components to the offspring. The offspring born to FI-RSV immunized mothers showed serum RSV neutralizing activity, effectively controlled lung viral loads without vaccine-enhanced disease, did not induce pulmonary eosinophilia, and cytokine producing cells after live RSV infection. Therefore, this study provides evidence that maternal immunization provides an in vivo model in investigating the roles of antibodies independent of cellular components.

Palivizumab prophylaxis during nosocomial outbreaks of respiratory syncytial virus in a neonatal intensive care unit: predicting effectiveness with an artificial neural network model

STUDY OBJECTIVE

To identify subgroups of premature infants who may benefit from palivizumab prophylaxis during nosocomial outbreaks of respiratory syncytial virus (RSV) infection.

DESIGN

Retrospective analysis using an artificial intelligence model.

SETTING

Level IIIB, 35-bed, neonatal intensive care unit (NICU) at a tertiary care hospital in the United Arab Emirates.

PATIENTS

One hundred seventy six premature infants, born at a gestational age of 22-34 weeks, and hospitalized during four RSV outbreaks that occurred between April 2005 and July 2007.

MEASUREMENTS AND MAIN RESULTS

We collected demographic and clinical data for each patient by using a standardized form. Input data consisted of seven categoric and continuous variables each. We trained, tested, and validated artificial neural networks for three outcomes of interest: mortality, days of supplemental oxygen, and length of NICU stay after the index case was identified. We compared variable impacts and performed reassignments with live predictions to evaluate the effect of palivizumab. Of the 176 infants, 31 (17.6%) received palivizumab during the outbreaks. All neural network configurations converged within 4 seconds in less than 400 training cycles. Infants who received palivizumab required supplemental oxygen for a shorter duration compared with controls (105.2 ± 7.2 days vs 113.2 ± 10.4 days, p=0.003). This benefit was statistically significant in male infants whose birth weight was less than 0.7 kg and who had hemodynamically significant congenital heart disease. Length of NICU stay after identification of the index case and mortality were independent of palivizumab use.

CONCLUSION

Palivizumab may be an effective intervention during nosocomial outbreaks of RSV in a subgroup of extremely low-birth-weight male infants with hemodynamically significant congenital heart disease.