Respiratory Syncytial Virus Infection among Hospitalized Infants in Four Middle-Income Countries

BACKGROUND

Understanding respiratory syncytial virus (RSV) global epidemiology is important to inform future prevention strategies.

METHODS

Hospitalized infants <1-year-old with acute illness were enrolled prospectively in Albania, Jordan, Nicaragua, and Philippines during respiratory seasons in 2015-2017. Medical chart review, parental interview, and post-discharge follow up were conducted. Respiratory specimens were tested using real-time RT-PCR for RSV. Infant characteristics associated with very severe illness (intensive care unit [ICU] admission or receipt of supplemental oxygen) were assessed using logistic regression to adjust for potential confounders (age, sex, study site, preterm birth).

RESULTS

Of 3,634 enrolled hospitalized infants, 1,129 (31%) tested positive for RSV. The median age of RSV-positive infants was 2.7 (IQR: 1.4 to 6.1) months and 665 (59%) were male. Very severe illness in 583 (52%) RSV-positive infants was associated with younger age (aOR 4.1, 95% CI: 2.6-6.5 for 0-2 compared to 9-11-months; p<0.01), , low weight-for-age z-score (aOR 1.9, 95%CI: 1.2-2.8; p<0.01), ICU care after birth (aOR 1.6, 95%CI: 1.0-2.5; p=0.48), and cesarean delivery (aOR 1.4, 95% CI: 1.0-1.8; p=.03). RSV subgroups A and B co-circulated at all sites with alternating predominance by year; subgroup was not associated with severity (aOR 1.0, 95% CI: 0.8-1.4). Nine (0.8%) RSV-positive infants died during admission or within ≤30 days of discharge, of which 7 (78%) were <6-months-old.

CONCLUSIONS

RSV was associated with nearly a third of infant acute illness hospitalizations in four middle-income countries during the respiratory season, where, in addition to young age, factors including low weight-for-age might be important predictors of severity. RSV prevention strategies targeting young infants could substantially reduce RSV-associated hospitalizations in middle-income countries.

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.

Severe Human Metapneumovirus and Group A Streptococcus Pneumonia in an Immunocompetent Adult

An immunocompetent adult with asthma developed severe human metapneumovirus (HMPV) illness complicated by group A Streptococcus coinfection, progressing to acute respiratory distress syndrome and shock. Several coworkers had less severe HMPV infection. HMPV can cause severe respiratory illness in healthy adults and should be considered as a potential cause of community respiratory outbreaks.

Results from the WHO external quality assessment for the respiratory syncytial virus pilot, 2016-17

Background

External quality assessments (EQAs) for the molecular detection of respiratory syncytial virus (RSV) are necessary to ensure the provision of reliable and accurate results. One of the objectives of the pilot of the World Health Organization (WHO) Global RSV Surveillance, 2016‐2017, was to evaluate and standardize RSV molecular tests used by participating countries. This paper describes the first WHO RSV EQA for the molecular detection of RSV.

Methods

The WHO implemented the pilot of Global RSV Surveillance based on the WHO Global Influenza Surveillance and Response System (GISRS) from 2016 to 2018 in 14 countries. To ensure standardization of tests, 13 participating laboratories were required to complete a 12 panel RSV EQA prepared and distributed by the Centers for Disease Control and Prevention (CDC), USA. The 14th laboratory joined the pilot late and participated in a separate EQA. Laboratories evaluated a RSV rRT‐PCR assay developed by CDC and compared where applicable, other Laboratory Developed Tests (LDTs) or commercial assays already in use at their laboratories.

Results

Laboratories performed well using the CDC RSV rRT‐PCR in comparison with LDTs and commercial assays. Using the CDC assay, 11 of 13 laboratories reported correct results. Two laboratories each reported one false‐positive finding. Of the laboratories using LDTs or commercial assays, results as assessed by Ct values were 100% correct for 1/5 (20%). With corrective actions, all laboratories achieved satisfactory outputs.

Conclusions

These findings indicate that reliable results can be expected from this pilot. Continued participation in EQAs for the molecular detection of RSV is recommended.

2629. Respiratory Syncytial Virus Epidemiology and Factors Associated with Severity among Hospitalized Infants in Four Middle-Income Countries, 2015–2017

Background

Respiratory syncytial virus (RSV) is the most commonly identified viral pathogen among young children with acute lower respiratory tract infection. Understanding global RSV epidemiology and risk factors for severe illness in low- and middle-income settings is critical as new vaccine candidates become available.

Methods

We prospectively enrolled infants aged < 1 year hospitalized with any acute illness from sites in Albania, Jordan, Nicaragua and Philippines during 2015–2017. Standardized parental interviews and medical record review were conducted. Respiratory specimens collected during enrollment were tested for RSV using rRT–PCR. RSV A or B subgroup was determined using a CDC-developed rRT–PCR assay. Very severe RSV illness was defined as requiring ICU admission or supplemental oxygen. Factors potentially associated with severity were assessed using individual logistic regression models to adjust for age and study site.

Results

Overall, 1,129 (31%) of 3634 enrolled infants had RSV infection. The median age of RSV-positive infants was 2.7 (range: < 1 to 11.9) months, 665 (59%) were male, and 63 (6%) had ≥1 underlying medical condition. RSV subgroup was determined for 1,028 (91%); RSV A and B co-circulated at all sites with alternating predominance by study year (figure). 583 (52%) infants had very severe RSV illness, which was significantly associated with younger age (median: 2.0 vs. 4.3 months; P < 0.01), study site (aOR: Jordan 5.0, Albania 2.9, Philippines 1.2, Nicaragua reference; P < 0.01), birth by cesarean section (aOR: 1.4; 95% CI [CI] 1.0–1.8; P = 0.03), having received ICU care after birth (aOR: 1.6; CI 1.0–2.4; P = 0.03), chronic heart or respiratory tract disease (aOR: 1.9; CI 1.0–3.4; P = 0.04), and a low weight-for-age Z score (aOR: 1.8; CI 1.3–2.7; P < 0.01). RSV subgroup was not associated with severity (aOR: 1.0; CI: 0.7–1.3; P = 0.72).

Conclusion

RSV was associated with a substantial proportion of acute illness among hospitalized infants in middle-income countries. Subgroups co-circulated across sites and study years with varying predominance and resulted in similar illness severity. Significant comorbidities were uncommon, but factors including younger age, low weight-for-age and chronic heart or respiratory tract disease were associated with more severe illness.

Disclosures

All authors: No reported disclosures.

2328. Human Respiratory Syncytial Virus Subgroups among Hospitalized Infants in the United States, 2015–2016

Background

Respiratory syncytial virus (RSV) is a major cause of severe acute respiratory illnesses (ARI) in young children. Circulation of RSV subgroups A and B can vary by season and geographic location, and may have implications for disease susceptibility, outcomes, and prevention measures. We investigated RSV subgroup distribution among samples collected in the New Vaccine Surveillance Network.

Methods

Prospective active surveillance for hospitalized ARI was conducted from November 1, 2015 to June 30, 2016 among children < 12 months of age at seven pediatric hospital sites. Mid-turbinate nasal and throat flocked swabs (combined when both available) and/or tracheal aspirates were collected and tested for RSV at each site using real-time reverse transcription polymerase chain reaction (rRT–PCR) assays; RSV A/B subgroup results were available from four sites that did their own subgroup testing (Cincinnati, Kansas City, Houston, and Oakland). At three sites (Rochester, Nashville, Seattle), approximately 50 RSV-positive specimens were sampled based on the monthly distribution for each site and 1:1 distribution by gender, and then assayed for subgroup at CDC. Patient information was obtained from medical records; chi-square tests were used to compare the distribution of A and B subgroups by site.

Results

Of 704 RSV-positive hospitalized infants, subgroup data from 586 were analyzed; 340 (58%) were RSV A and 246 (42%) were RSV B. The median age for both RSV A and RSV B patients was 2 months. Subgroup distribution varied by geographic location, with the overall proportion of RSV A ranging from 18–83% across sites (P < 0.01). Peak RSV A and B detections by month varied by site, occurring from November–February (figure).

Conclusion

During the 2015–2016 season, RSV A and B subgroups co-circulated among hospitalized infants enrolled at seven US sites. The predominance of RSV subgroup varied by geographic location. Continued surveillance and additional subgroup testing over multiple seasons should improve understanding of the epidemiologic significance of RSV infections by subgroup.

Disclosures

All authors: No reported disclosures.

Severe Respiratory Illness Associated with Human Metapneumovirus in Nursing Home, New Mexico, USA

Human metapneumovirus is an emerging pathogen that causes upper and lower respiratory illness. Nursing home outbreaks of infection with this virus can cause severe illness and lead to poor patient outcomes. We report an outbreak investigation in a nursing home during 2018 and infection control guidelines to assist in disease control.

Cell culture and electron microscopy for identifying viruses in diseases of unknown cause

During outbreaks of infectious diseases or in cases of severely ill patients, it is imperative to identify the causative agent. This report describes several events in which virus isolation and identification by electron microscopy were critical to initial recognition of the etiologic agent, which was further analyzed by additional laboratory diagnostic assays. Examples include severe acute respiratory syndrome coronavirus, and Nipah, lymphocytic choriomeningitis, West Nile, Cache Valley, and Heartland viruses. These cases illustrate the importance of the techniques of cell culture and electron microscopy in pathogen identification and recognition of emerging diseases.

Transcriptional adaptation of pneumococci and human pharyngeal cells in the presence of a virus infection

Background

Viral upper respiratory tract infections are associated with increased colonization by Streptococcus pneumoniae but the mechanisms underlying this relationship are unclear. The objective of this study is to describe a comprehensive picture of the cellular interaction between the adhering bacteria and host cells in the presence or absence of a viral co-infection.

Results

Gene expression profiles of Detroit-562 pharyngeal cells, which were either mock-infected or infected with human respiratory syncytial virus (RSV) or human parainfluenza virus 3 (HPIV3), were analyzed using human microarrays. Transcription response of S. pneumoniae strain TIGR4 (serotype 4) in the presence of either mock- or viral-infected cells was analyzed by pneumococcal microarray. Significantly regulated genes were identified by both significance analysis of microarray (SAM) and a ≥ 2-fold change ratio cut-off. The adherence of S. pneumoniae to human pharyngeal cells was significantly augmented in the presence of RSV or HPIV3 infection. Global gene expression profiling of the host cells during infection with RSV or HPIV3 revealed increased transcription of carcinoembryonic antigen-related cell adhesion molecules (CEACAM1), CD47, fibronectin, interferon-stimulated genes and many other host cell adhesion molecules. Pneumococci increased transcription of several genes involved in adhesive functions (psaA, pilus islet), choline uptake and incorporation (lic operon), as well as transport and binding.

Conclusions

We have identified a core transcriptome that represents the basic machinery required for adherence of pneumococci to D562 cells infected or not infected with a virus. These bacterial genes and cell adhesion molecules can potentially be used to control pneumococcal adherence occurring secondary to a viral infection.

Hospitalization due to human parainfluenza virus-associated lower respiratory tract illness in rural Thailand

Background  Human parainfluenza viruses (HPIVs) are an important cause of acute respiratory illness in young children but little is known about their epidemiology in the tropics.

Methods  From 2003–2007, we conducted surveillance for hospitalized respiratory illness in rural Thailand. We performed reverse‐transcriptase polymerase chain reaction on nasopharyngeal specimens and enzyme immunoassay on paired sera

Results  Of 10,097 patients enrolled, 573 (5%) of all ages and 370 (9%) of children <5 years of age had evidence of HPIV infection (HPIV1=189, HPIV2=54, HPIV3=305, untyped=27). Average adjusted annual incidence of HPIV‐associated hospitalized respiratory illness was greatest in children aged <1 year (485 per 100,000 person years).

Conclusions  In Thailand, HPIV caused substantial illnesses requiring hospitalization in young children.

The burden of hospitalized lower respiratory tract infection due to respiratory syncytial virus in rural Thailand

Background

We describe the epidemiology of hospitalized RSV infections for all age groups from population-based surveillance in two rural provinces in Thailand.

Methods

From September 1, 2003 through December 31, 2007, we enrolled hospitalized patients with acute lower respiratory tract illness, who had a chest radiograph ordered by the physician, from all hospitals in SaKaeo and Nakhom Phanom Provinces. We tested nasopharyngeal specimens for RSV with reverse transcriptase polymerase chain reaction (RT-PCR) assays and paired-sera from a subset of patients with IgG enzyme immunoassay. Rates were adjusted for enrollment.

Results

Among 11,097 enrolled patients, 987 (8.9%) had RSV infection. Rates of hospitalized RSV infection overall (and radiographically-confirmed pneumonia) were highest among children aged <1 year: 1,067/100,000 (534/100,000 radiographically-confirmed pneumonia) and 1–4 year: 403/100,000 (222/100,000), but low among enrolled adults aged ≥65 years: 42/100,000. Age <1 year (adjusted odds ratio [aOR]  = 13.2, 95% confidence interval [CI] 7.7, 22.5) and 1–4 year (aOR = 8.3, 95% CI 5.0, 13.9) were independent predictors of hospitalized RSV infection.

Conclusions

The incidence of hospitalized RSV lower respiratory tract illness among children <5 years was high in rural Thailand. Efforts to prevent RSV infection could substantially reduce the pneumonia burden in children aged <5 years.

Human bocavirus species 2 and 3 in Brazil

BACKGROUND

The newly described human bocavirus (HBoV) species 2 and 3 have been repeatedly detected in stool strengthening the possibility that these viruses might present a tropism for the gastrointestinal tract and may be etiological agents of diarrhea.

OBJECTIVE

In this study we assessed the presence of HBoV2 and HBoV3 in stool specimens from Brazilians with acute gastroenteritis.

STUDY DESIGN

Stool samples from Brazilian patients with acute diarrhea were analyzed for HBoV2 and HBoV3 by PCR assay. Full or partial genome sequences were obtained for selected isolates. Electron microscopy analysis was used to investigate virus morphology.

RESULTS

Electron microscopy confirmed the presence of virus-like particles in HBoV PCR-positive specimens, with morphology similar to other members of the Parvoviridae family. Five samples out of 807 (0.6%) were positive for HBoV3. Three of the HBoV3-positive patients were HIV/AIDS positive. A selected group of 144 samples was also tested for HBoV2 and 30 samples (20.8%) were positive, 11 of which were HIV/AIDS positive.

CONCLUSION

This study reports the detection and genetic characterization of HBoV3 and HBoV2 in the stool of Brazilian patients with acute diarrhea. This is the first description of HBoV3 outside Australia, suggesting a wide global distribution of this virus. Further studies are needed to better understand the role of HBoV in gastrointestinal infections, particularly among patients with HIV/AIDS.

Who gets hospitalized for influenza pneumonia in Thailand? Implications for vaccine policy

Risk factor information for severe complications of interpandemic influenza is needed to inform vaccine policy in Thailand. We identified patients with lab-confirmed influenza who were hospitalized with pneumonia during September 2003 to August 2004. Among the 80 case-patients identified through a population-based pneumonia surveillance system in eastern Thailand, cases were 6.2 and 11.1 times more likely to be among persons<1 year old and >75 years old, respectively, compared with the overall population. Cases were also 7.6 times more likely to have chronic respiratory disease. In Thailand, the young, elderly, and those with chronic disease were at high risk for hospitalized pneumonia from influenza.

Detection of human metapneumovirus in clinical samples by immunofluorescence staining of shell vial centrifugation cultures prepared from three different cell lines

Monoclonal antibody MAb-8 was evaluated for detection of human metapneumovirus (HMPV) in shell vial centrifugation cultures (SVCC). Detection of HMPV was similar in A549, HEp-2, and LLC-MK2 SVCC, and MAb-8 staining was optimal on day 2 postinoculation. Availability of SVCC for HMPV will be of significant benefit to clinical laboratories.

Sequence polymorphism of the predicted human metapneumovirus G glycoprotein

The putative G glycoprotein genes of 25 human metapneumovirus (hMPV) field isolates obtained during five consecutive epidemic seasons (1997 to 2002) were sequenced. Sequence alignments identified two major genetic groups, designated groups 1 and 2, and two minor genetic clusters within each major group, designated subgroups A and B. Extensive nucleotide and deduced amino acid sequence variability was observed, consisting of high rates of nucleotide substitutions, use of alternative transcription-termination codons and insertions that retained the reading frame. Deduced amino acid sequences showed the greatest variability, with most differences located in the extracellular domain of the protein: nucleotide and amino acid sequence identities for the entire open reading frame ranged from 52 to 58 % and 31 to 35 %, respectively, between the two major groups. Like the closely related avian pneumovirus and human and bovine respiratory syncytial viruses, the predicted G protein of hMPV shared the basic features of a type II mucin-like glycosylated protein. However, differences from these related viruses were also observed, e.g. lack of conserved cysteine clusters as seen in human respiratory syncytial virus and avian pneumovirus. The displacement of genetic groups of hMPV observed during the study period suggests that potential antigenic differences in the G glycoprotein, which have evolved in response to immune-mediated pressure, may influence the circulation patterns of hMPV strains.

SARS surveillance during emergency public health response, United States, March-July 2003

In response to the emergence of severe acute respiratory syndrome (SARS), the United States established national surveillance using a sensitive case definition incorporating clinical, epidemiologic, and laboratory criteria. Of 1,460 unexplained respiratory illnesses reported by state and local health departments to the Centers for Disease Control and Prevention from March 17 to July 30, 2003, a total of 398 (27%) met clinical and epidemiologic SARS case criteria. Of these, 72 (18%) were probable cases with radiographic evidence of pneumonia. Eight (2%) were laboratory-confirmed SARS-coronavirus (SARS-CoV) infections, 206 (52%) were SARS-CoV negative, and 184 (46%) had undetermined SARS-CoV status because of missing convalescent-phase serum specimens. Thirty-one percent (124/398) of case-patients were hospitalized; none died. Travel was the most common epidemiologic link (329/398, 83%), and mainland China was the affected area most commonly visited. One case of possible household transmission was reported, and no laboratory-confirmed infections occurred among healthcare workers. Successes and limitations of this emergency surveillance can guide preparations for future outbreaks of SARS or respiratory diseases of unknown etiology.

Characterization of a novel coronavirus associated with severe acute respiratory syndrome

In March 2003, a novel coronavirus (SARS-CoV) was discovered in association with cases of severe acute respiratory syndrome (SARS). The sequence of the complete genome of SARS-CoV was determined, and the initial characterization of the viral genome is presented in this report. The genome of SARS-CoV is 29,727 nucleotides in length and has 11 open reading frames, and its genome organization is similar to that of other coronaviruses. Phylogenetic analyses and sequence comparisons showed that SARS-CoV is not closely related to any of the previously characterized coronaviruses.

Sequence analysis of the N, P, M and F genes of Canadian human metapneumovirus strains

The complete nucleotide sequences of the nucleoprotein (N), phosphoprotein (P), matrix protein (M), and fusion protein (F) genes of 15 Canadian human metapneumovirus (hMPV) isolates were determined. Phylogenetic analysis revealed two distinct genetic clusters, or groups for each gene with additional sequence variability within the individual groups. Comparison of the deduced amino acid sequences for the N, M and F genes of the different isolates revealed that all three genes were well conserved with 94.1-97.6% identity between the two distinct clusters The P gene showed more diversity with 81.6-85.7% amino acid identity for isolates between the two clusters, and 94.6-100% for isolates within the same cluster.

Virological features and clinical manifestations associated with human metapneumovirus: a new paramyxovirus responsible for acute respiratory-tract infections in all age groups

The virological features and clinical findings associated with the new human metapneumovirus (HMPV) were examined retrospectively in Canadian patients hospitalized for various respiratory conditions since 1993. Thirty-eight previously unidentified respiratory viruses isolated from rhesus monkey kindey (LLC-MK2) cells were found to be positive for HMPV by reverse-transcription polymerase chain reaction, and those strains clustered in 2 phylogenetic groups. Children aged <5 years and elderly subjects aged >65 years represented 35.1% and 45.9% of the HMPV-infected cases, respectively. In hospitalized children, the most frequent diagnoses were pneumonitis (66.7%) and bronchiolitis (58.3%), whereas bronchitis and/or bronchospasm (60%) and pneumonitis (40%) were most commonly seen in elderly subjects. Of the 15 patients with pneumonitis, 4 (26.7%) had immunosuppressive conditions and 6 (40%) were infants aged <15 months. These findings suggest that HMPV can be associated with severe lower-respiratory-tract infections in very young children, the elderly, and immunocompromised patients.

Characterization of human metapneumoviruses isolated from patients in North America

Human metapneumovirus (HMPV) was recently identified in The Netherlands and was linked to acute respiratory tract illness. In this study, 11 isolates from 10 patients with respiratory disease from Quebec, Canada, were tested by a reverse-transcriptase polymerase chain reaction based on the fusion protein gene. Identified sequences were consistent with HMPV. The patients were 2 months to 87 years of age (median age, 58 years) and presented with acute respiratory tract illness during the winter season. Sequence studies of the nucleocapsid, fusion, and polymerase genes identified 2 main lineages of HMPV and cocirculation of both lineages during the same year. These findings support a previous finding that HMPV is a human respiratory pathogen that merits further study.

Multiplex assay for detection of strain-specific antibodies against the two variable regions of the G protein of respiratory syncytial virus

The role of strain differences in respiratory syncytial virus (RSV) disease has not been clearly defined. To investigate the possibility that strain differences contribute to susceptibility to repeat infections, we developed assays to detect antibodies to the two variable regions of the RSV G protein by cloning and expressing the internal variable region at amino acids (aa) 60 to 172 (g1) and the carboxy-terminal variable region at aa 193 to the carboxy terminus (g2) from different genotypes of RSV. The purified proteins were covalently linked to beads with different proportions of red and orange fluorescent dyes and reacted against serum specimens. Antibody reacting against the differently colored beads, and thus against different G polypeptides, was detected by use of flow cytometry and the Luminex system. This assay system detected group- and, to some extent, genotype-specific responses to RSV infection and can be used to investigate the role of strain differences in RSV disease.