Does respiratory syncytial virus lower respiratory illness in early life cause recurrent wheeze of early childhood and asthma? Critical review of the evidence and guidance for future studies from a World Health Organization-sponsored meeting

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection (LRTI) and hospitalization in infants and children globally. Many observational studies have found an association between RSV LRTI in early life and subsequent respiratory morbidity, including recurrent wheeze of early childhood (RWEC) and asthma. Conversely, two randomized placebo-controlled trials of efficacious anti-RSV monoclonal antibodies (mAbs) in heterogenous infant populations found no difference in physician-diagnosed RWEC or asthma by treatment group. If a causal association exists and RSV vaccines and mAbs can prevent a substantial fraction of RWEC/asthma, the full public health value of these interventions would markedly increase. The primary alternative interpretation of the observational data is that RSV LRTI in early life is a marker of an underlying predisposition for the development of RWEC and asthma. If this is the case, RSV vaccines and mAbs would not necessarily be expected to impact these outcomes. To evaluate whether the available evidence supports a causal association between RSV LRTI and RWEC/asthma and to provide guidance for future studies, the World Health Organization convened a meeting of subject matter experts on February 12-13, 2019 in Geneva, Switzerland. After discussing relevant background information and reviewing the current epidemiologic evidence, the group determined that: (i) the evidence is inconclusive in establishing a causal association between RSV LRTI and RWEC/asthma, (ii) the evidence does not establish that RSV mAbs (and, by extension, future vaccines) will have a substantial effect on these outcomes and (iii) regardless of the association with long-term childhood respiratory morbidity, severe acute RSV disease in young children poses a substantial public health burden and should continue to be the primary consideration for policy-setting bodies deliberating on RSV vaccine and mAb recommendations. Nonetheless, the group recognized the public health importance of resolving this question and suggested good practice guidelines for future studies.

Blood Viral Load in Symptomatic Congenital Cytomegalovirus Infection

BACKGROUND

Viral loads (VLs) frequently are followed during treatment of symptomatic congenital cytomegalovirus disease, but their predictive value is unclear.

METHODS

Post hoc analysis of 2 antiviral studies was performed. Seventy-three subjects were treated for 6 weeks and 47 subjects were treated for 6 months. Whole blood VL was determined by real-time polymerase chain reaction before and during therapy.

RESULTS

Higher baseline VL was associated with central nervous system involvement (3.82 log, range 1-5.65 vs 3.32 log, range 1-5.36; P = .001), thrombocytopenia (3.68 log, range 1-5.65 vs 3.43 log, range 1-5.36; P = .03), and transaminitis at presentation (3.73 log, range 1-5.60 vs 3.39 log, range 1-5.65; P = .009), but with overlap in the amount of virus detected between groups. In subjects treated for 6 months, lower VL at presentation correlated with better hearing outcomes at 12 months, but VL breakpoints predictive of hearing loss were not identified. Sustained viral suppression during 6 months of therapy correlated with better hearing outcomes at 6, 12, and 24 months (P = .01, P = .0007, P = .04), but a majority without viral suppression still had improved hearing.

CONCLUSIONS

In infants with symptomatic congenital cytomegalovirus disease, higher whole blood VL before initiation of antiviral therapy has no clinically meaningful predictive value for long-term outcomes.

Vaccine Oka Varicella Meningitis in Two Adolescents

The live-attenuated varicella vaccine, a routine immunization in the United States since 1995, is both safe and effective. Like wild-type varicella-zoster virus, however, vaccine Oka (vOka) varicella can establish latency and reactivate as herpes zoster, rarely leading to serious disease, particularly among immunocompromised hosts. Previous cases of reactivated vOka resulting in meningitis have been described in young children who received a single dose of varicella vaccine; less is known about vOka reactivation in older children after the 2-dose vaccine series. We present 2 adolescents with reactivated vOka meningitis, 1 immunocompetent and 1 immunocompromised, both of whom received 2 doses of varicella vaccine many years before as children. Pediatricians should be aware of the potential of vOka varicella to reactivate and cause clinically significant central nervous system disease in vaccinated children and adolescents.

Risk of Respiratory Infection following Diarrhea among Adult Women and Infants in Nepal

Globally, diarrheal and respiratory infections are responsible for more than 24% of deaths in children aged less than 5 years. Historically, these disease entities have been studied separately; recent evidence suggests that preceding diarrheal disease may be a risk factor for subsequent respiratory illness. We used data from a community-based, prospective randomized trial of maternal influenza immunization of 3,693 pregnant women and their 3,646 infants conducted in rural Nepal from 2011 to 2014. A case-crossover design was used to determine whether the risk of respiratory infection in the 30 days following a diarrheal episode was increased compared with that 30 days prior. Diarrheal illness was a significant risk factor for subsequent respiratory illness in infants but not in women during pregnancy or in women up to six months postpartum. Diarrheal illness and respiratory infections remain important global sources of morbidity and mortality, and our study supports a causal relationship between them in infants.

Breast Milk Prefusion F Immunoglobulin G as a Correlate of Protection Against Respiratory Syncytial Virus Acute Respiratory Illness

Background

Transplacental respiratory syncytial virus (RSV) antibody transfer has been characterized, but little is known about the protective effect of breast milk RSV-specific antibodies. Serum antibodies against the prefusion RSV fusion protein (pre-F) exhibit high neutralizing activity. We investigate protection of breast milk pre-F antibodies against RSV acute respiratory infection (ARI).

Methods

Breast milk at 1, 3, and 6 months postpartum and midnasal swabs during infant illness episodes were collected in mother-infant pairs in Nepal. One hundred seventy-four infants with and without RSV ARI were matched 1:1 by risk factors for RSV ARI. Pre-F immunoglobulin A (IgA) and immunoglobulin G (IgG) antibody levels were measured in breast milk.

Results

The median breast milk pre-F IgG antibody concentration before illness was lower in mothers of infants with RSV ARI (1.4 [interquartile range {IQR}, 1.1-1.6] log10 ng/mL) than without RSV ARI (1.5 [IQR, 1.3-1.8] log10 ng/mL) (P = .001). There was no difference in median maternal pre-F IgA antibody concentrations in cases vs controls (1.7 [IQR, 0.0-2.2] log10 ng/mL vs 1.7 [IQR, 1.2-2.2] log10 ng/mL, respectively; P = .58).

Conclusions

Low breast milk pre-F IgG antibodies before RSV ARI support a potential role for pre-F IgG as a correlate of protection against RSV ARI. Induction of breast milk pre-F IgG may be a mechanism of protection for maternal RSV vaccines.

Viral Etiology of Acute Gastroenteritis in <2-Year-Old US Children in the Post-Rotavirus Vaccine Era

BACKGROUND

The rotavirus disease burden has declined substantially since rotavirus vaccine was introduced in the United States in 2006. The aim of this study was to determine the viral etiology of acute gastroenteritis (AGE) in US children aged <2 years.

METHODS

The New Vaccine Surveillance Network (NVSN) of geographically diverse US sites conducts active pediatric population-based surveillance in hospitals and emergency departments. Stool samples were collected from children aged <2 years with symptoms of AGE (n = 330) and age-matched healthy controls (HCs) (n = 272) between January and December 2012. Samples were tested by real-time reverse-transcriptase polymerase chain reaction assays {adenovirus (type 40 and 41), norovirus, parechovirus A, enterovirus, sapovirus, and astrovirus} and an enzyme immunoassay (rotavirus). All samples that tested positive were genotyped.

RESULTS

Detection rates of pathogens in children with AGE versus those of HCs were, respectively, 23.0% versus 6.6% for norovirus (P < .01), 23.0% versus 16.0% for adenovirus (P = .08), 11.0% versus 16.0% for parechovirus A (P = .09), 11.0% versus 9.0% for enterovirus (P = .34), 7.0% versus 3.0% for sapovirus (P = .07), 3.0% versus 0.3% for astrovirus (P = .01), and 3.0% versus 0.4% for rotavirus (P = .01). A high prevalence of adenovirus was detected at 1 surveillance site (49.0% for children with AGE and 43.0% for HCs). Norovirus GII.4 New Orleans was the most frequently detected (33.0%) norovirus genotype. Codetection of >1 virus was more common in children with AGE (16.0%) than in HCs (10.0%) (P = .03).

CONCLUSIONS

Norovirus, astrovirus, sapovirus, and rotavirus were detected significantly more in children with AGE than in HCs, and norovirus was the leading AGE-causing pathogen in US children aged <2 years during the year 2012.

Burden and Risk Factors for Coronavirus Infections in Infants in Rural Nepal

Background

Knowledge of risk factors for symptomatic human coronavirus (HCoV) infections in children in community settings is limited. We estimated the disease burden and impact of birth-related, maternal, household, and seasonal factors on HCoV infections among children from birth to 6 months old in rural Nepal.

Methods

Prospective, active, weekly surveillance for acute respiratory infections (ARIs) was conducted in infants over a period of 3 years during 2 consecutive, population-based randomized trials of maternal influenza immunization. Midnasal swabs were collected for acute respiratory symptoms and tested for HCoV and other viruses by reverse-transcription polymerase chain reaction. Association between HCoV incidence and potential risk factors was modeled using Poisson regression.

Results

Overall, 282 of 3505 (8%) infants experienced an HCoV ARI within the first 6 months of life. HCoV incidence overall was 255.6 (95% confidence interval [CI], 227.3–286.5) per 1000 person-years, and was more than twice as high among nonneonates than among neonates (incidence rate ratio [IRR], 2.53; 95% CI, 1.52–4.21). HCoV ARI incidence was also positively associated with the number of children <5 years of age per room in a household (IRR, 1.13; 95% CI, 1.01–1.28). Of the 296 HCoV infections detected, 46% were coinfections with other respiratory viruses. While HCoVs were detected throughout the study period, seasonal variation was also observed, with incidence peaking in 2 winters (December–February) and 1 autumn (September–November).

Conclusions

HCoV is associated with a substantial proportion of illnesses among young infants in rural Nepal. There is an increased risk of HCoV infection beyond the first month of life.

LB21. The Seattle Flu Study: A Community-Based Study of Influenza

Background

Influenza epidemics and pandemics cause significant morbidity and mortality. An effective response to a potential pandemic requires the infrastructure to rapidly detect and contain new and emerging flu strains at a population level. The objective of this study was to use data gathered simultaneously from community and hospital sites to develop a model of how flu enters and spreads in a population.

Methods

In the 2018–2019 season, we enrolled individuals with respiratory illness from community sites throughout the Seattle area, including homeless shelters, childcare facilities, Seattle-Tacoma International Airport, workplaces, college campuses, clinics, and at home (Figure 1). We collected data and nasal swabs from individuals with at least two respiratory symptoms. Additionally, we collected residual nasal swabs and data from individuals who sought care at four regional hospitals. Home-based self-testing for influenza and prediction models for influenza were piloted. Swabs were tested with a multiplex molecular assay, and influenza whole-genome sequencing was performed. Geospatial mapping and computational modeling platforms were developed to characterize regional spread of respiratory pathogens.

Results

A total of 18,847 samples were collected in the 2018–2019 season. Of those tested to date, 291/3,653 (8%) community and 2,393/11,273 (21%) hospital samples have influenza detected. Of the community enrollments, 39% had influenza-like illness. Community enrollees were in age groups not well-represented from hospitals. Influenza A/H3N2 activity peaked on college campuses and homeless shelters 2 weeks before the peak in hospitals. We observed multiple independent introductions of influenza strains into the city and evidence of sustained transmission chains within the city (Figures 2 and 3).

Conclusion

Utilizing the city-wide infrastructure we developed, we observed the introduction of influenza A/H3N2 into the community before the hospital and evidence of transmissions of unique strains into and within the Seattle area. These data provide the blueprint for implementing city-wide, community-based surveillance systems for rapid detection, real-time assessment of transmission patterns, and interruption of spread of seasonal or pandemic strains.

Disclosures

Helen Y. Chu, MD MPH, Merck (Advisor or Review Panel member), Michael Boeckh, MD PhD, Ablynx (Consultant, Grant/Research Support), Ansun Biopharma (Consultant, Grant/Research Support), Bavarian Nordic (Consultant), Gilead (Consultant, Grant/Research Support), GlaxoSmithKline (Consultant), Vir Bio (Consultant, Grant/Research Support), Janet A. Englund, MD, Chimerix (Grant/Research Support), GlaxoSmithKline (Grant/Research Support), MedImmune/Astrazeneca (Grant/Research Support), Meissa Vaccines (Consultant), Merck (Grant/Research Support),Novavax (Grant/Research Support), Sanofi Pastuer (Consultant), Matthew Thompson, MD, Alere Inc. (Research Grant or Support), Roche Molecular Diagnostics (Consultant, Research Grant or Support, Speaker’s Bureau), . Other Authors: No reported disclosures.

2738. Influenza Vaccination During Pregnancy Among Mothers of Infants with Acute Respiratory Illness, United States, 2016–2018

Background

Influenza vaccination has been shown to reduce influenza risk in pregnant women and their infants who are not yet age-eligible for vaccine. Ascertainment of vaccination history is important for vaccine safety and effectiveness evaluations. Our goals were to (a) determine coverage, location, and timing of maternal influenza vaccination and (b) compare a subset of self-reported influenza vaccinations with documented vaccine records.

Methods

We enrolled children < 18 years. with acute respiratory illness in 7 pediatric hospitals and emergency departments in the New Vaccine Surveillance Network from December 1, 2016 to October 31, 2018. We interviewed all mothers of enrolled infants < 1 year, and obtained mother’s influenza vaccine information while pregnant. As an option, sites obtained maternal influenza vaccine records from reported sources (e.g., registries, provider records, pharmacies).

Results

Among 5,458 mothers, 2,944 (54%) self-reported receiving influenza vaccine during pregnancy (57% in 2016–2017; 51% in 2017–2018), varying from 49% to 74% by site. Among self-reported vaccinees, 17%, 36%, and 47% received vaccine during their first, second, and third trimester, respectively. Most women (76%) were vaccinated at their OB/GYN or midwife office, 7% at their primary care provider, 7% at their workplace, and 5% at a retail pharmacy. Among 1,338 infants < 6 months. during early influenza season (i.e., born from June to August) and thus ineligible for vaccination, only 46% of mothers reported receiving vaccine during pregnancy (42% reported not receiving it, 12% were unsure). Of 2,242 women for whom vaccine verification was attempted, 1,491 (67%) self-reported receiving influenza vaccine during pregnancy; of those, documentation of vaccine receipt was found for 901 (60%).

Conclusion

Influenza vaccination coverage among pregnant women was suboptimal, potentially increasing the risk of influenza in unvaccinated pregnant women. Infants born to unvaccinated women, particularly those born from June to August, may also be at higher risk since they are not age-eligible to receive vaccine before influenza season. The optimal approach to ascertainment of maternal vaccination history with accuracy and completeness merits further investigation.

Disclosures

All authors: No reported disclosures.

Langley J, Leach A, Madhi SA, Maleux K, Lien-Anh Nguyen T, Puthanakit T, Silas P, Stoszek SK, Tangsathapornpong A, Teeratakulpisarn J, Virta M, Zaman K. 2855. Respiratory Syncytial Virus Neutralizing Antibodies in Cord Blood and Serum from Infants up to 2 Years of Age in a Multinational Prospective Study

Background

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infections (LRTI) during infancy worldwide. High cord blood (CB) concentrations of anti-RSV neutralizing antibody (nAb) may attenuate, delay, or prevent infant infection. We report RSV A and B nAb concentrations in CB and serum from a birth cohort at different time points through 2 years of age.

Methods

Between 2013 and 2017, newborns from 8 countries were studied prospectively from birth to 2 years of age (NCT01995175). CB was collected at birth for the entire cohort. A subcohort of children was randomly assigned to have one blood sample collected again at either 2, 4, 6, 12, 18, or 24 months of age. Sera were analyzed for RSV A and B nAb concentrations by serum neutralization assay. Active surveillance was used to identify LRTIs during the 2-year follow-up as previously reported.

Results

In total, 2,401 newborns were enrolled and followed up. >99% of infants had detectable CB RSV A and B nAb. Geometric mean antibody titers (GMTs) varied by country, but were overall higher for RSV B than for RSV A (327 vs. 251; Figure 1). The lowest GMTs were seen from CB sera collected from South African newborns (197 RSV A, 255 RSV B); Canadian newborns had the highest RSV A GMT (383), while Hondurans had the highest RSV B GMT (460). 1380 infants provided follow-up serum nAb results as part of the subcohort (Figure 2). Dramatic waning of GMTs was evident, with a ~3-fold drop in GMTs at 2 months of age, and an additional ~2-fold drop between 2 and 4 months of age. At 6 and 12 months of age, 71% and 50% of infants had RSV A nAb and GMTs were at a nadir of 14. At 6, 12, and 18 months of age, RSV B nAb was detected in 98%, 69%, and 63% of infants, respectively. The RSV B nAb nadir GMT of 20 was observed at 12 months of age, while the 6- and 18-month RSV B nAb GMTs were 30 and 31, respectively. A total of 1,017 LRTIs were identified during the 2-year study period; of which, 94 (9%) were caused by RSV A and 132 (13%) by RSV B. Associations between CB nAb levels and RSV infection will be presented.

Conclusion

Neutralizing Ab to RSV A and B was present at birth in infants from 8 countries, and waned over time. GMTs were at a nadir at 6 to 12 months of age.

Funding. GlaxoSmithKline Biologicals SA.

Disclosures

All Authors: No reported Disclosures.

899. Influenza Vaccine Effectiveness Against Laboratory-Confirmed Influenza in Children Hospitalized with Respiratory Illness in the United States, 2016–2017 and 2017–2018 Seasons

Background

Annual national estimates of influenza vaccine effectiveness (VE) typically measure protection against outpatient medically attended influenza illness. We assessed influenza VE in preventing laboratory-confirmed influenza hospitalization in children across two influenza A(H3N2)-predominant seasons.

Methods

Children < 18 years hospitalized with acute respiratory illness were enrolled at 7 pediatric hospitals in the New Vaccine Surveillance Network. We included subjects ≥6 months with ≤10 days of symptoms enrolled during the 2016–2017 and 2017–2018 seasons (date of first through last influenza-positive case for each site). Combined mid-turbinate and throat swabs were tested using molecular assays. We estimated age-stratified VE from a test-negative design using logistic regression to compare the odds of vaccination among cases positive for influenza with controls testing negative, adjusting for age, enrollment month, site, underlying comorbidities, and race/ethnicity. Full/partial vaccination was defined using ACIP criteria. We verified vaccine receipt from state immunization registries and/or provider records.

Results

Among 3441 children with complete preliminary data, in 2016–2017, 156/1,710 (9%) tested positive for influenza: 91 (58%) with influenza A(H3N2), 5 (3%) with A(H1N1), and 60 (38%) with B viruses. In 2017–2018, 193/1,731 (11%) tested positive: 87 (45%) with influenza A(H3N2), 47 (24%) with A(H1N1), and 58 (30%) with B. VE for all vaccinated children (full and partial) against any influenza was 48% (95% confidence interval, 26%–63%) in 2016–2017 and 45% (24%–60%) in 2017–2018. Combining seasons, VE for fully and partially vaccinated children against any influenza type was 46% (32%–58%); by virus, VE was 30% (4%–49%) for influenza A(H3N2), 71% (46%–85%) for A(H1N1), and 57% (36%–70%) for B viruses. There was no statistically significant difference in VE by age or full/partial vaccination status for any virus (table).

Conclusion

Vaccination in the 2016–2017 and 2017–2018 seasons nearly halved the risk of children being hospitalized with influenza. These findings support the use of vaccination to prevent severe illness in children. Our study highlights the need for a better understanding of the lower VE against influenza A(H3N2) viruses.

Disclosures

All Authors: No reported Disclosures.

2318. Prevalence of Influenza-like Illness in Sheltered Homeless Populations: A Cross-Sectional Study in Seattle, WA

Background

Individuals experiencing homelessness are at an increased risk of respiratory illness due to high prevalence of underlying chronic conditions, inadequate ventilation and crowding in shelters, and difficulty accessing health services. Few studies have investigated the prevalence and transmission of viral respiratory infections within shelters. We sought to determine the prevalence and risk factors for influenza-like illness (ILI) at two homeless shelters in Seattle, WA.

Methods

Between January and April 2019, we conducted a cross-sectional study of adults experiencing homelessness who identified their primary residence as one of the two shelters in Seattle. Participants voluntarily enrolled if they self-reported at least two symptoms of acute respiratory illness in the past week. Demographic, clinical, and behavioral data were ascertained via questionnaire, and a mid-nasal swab was collected. ILI was defined as fever with cough or sore throat. Chronic lung disease was defined as chronic obstructive pulmonary disease, asthma, and/or chronic bronchitis.

Results

Among the 480 participants enrolled in the study, 204 (42.5%) reported ILI symptoms. Of those enrolled, 144 (30.0%) had chronic lung disease. The prevalence of ILI was higher among individuals with chronic lung disease (53.5% vs. 42.5%, P = 0.001). A total of 422 (87.9%) had health insurance; the prevalence of ILI was lower among those with health insurance (42.4% vs. 57.8%, P = 0.66). 216 (45.0%) of participants received flu vaccine; the prevalence of ILI was similar among those who received the vaccine than those that did not (42.6% vs. 42.4%, P = 1.00). 129 (30.6%) of those with health insurance sought care for their reported symptoms; ILI was more prevalent in those that sought care than those that did not throughout the observation period (33.8% vs. 21.7%, P = 0.002). Of those with ILI that sought care, 46 (54.8%, P = 0.42) received antivirals or antibiotics. Laboratory results for the corresponding mid-nasal swabs are pending.

Conclusion

A large proportion of our study population self-reported ILI and chronic lung disease. Despite high insurance coverage, a low proportion of homeless enrolled sought care for their symptoms or received treatment.

Disclosures

All authors: No reported disclosures.

2639. Respiratory Virus Detections in Asthma-Related Pediatric Hospitalizations: New Vaccine Surveillance Network, United States

Background

Respiratory viruses are associated with most asthma exacerbations (AEx) in children; however, the role of different viruses in AEx is unclear. We describe respiratory virus detections among pediatric inpatients with AEx (AEx-inpatients).

Methods

Through active, prospective surveillance at 7 US medical centers, we enrolled inpatients (<18 years) with acute respiratory illness (ARI) during November 1, 2015–June 30, 2016. We defined an AEx-inpatient as an inpatient with a principal admission or discharge diagnosis of asthma (ICD-10-CM, J45.xx). Mid-turbinate nasal and/or throat swabs were tested by molecular assays for influenza A or B, respiratory syncytial virus (RSV), parainfluenza virus 1–3, rhinovirus or enterovirus (RV/EV), human metapneumovirus and adenovirus. We assessed virus detections among AEx-inpatients throughout the surveillance period or by season (winter: December–February; spring: March–May), and by patient age and history of asthma/reactive airway disease (asthma/RAD).

Results

We tested 3,897 inpatients with ARI; of whom, 954 were AEx-inpatients. Most AEx-inpatients (741/954 [78%]) reported an asthma/RAD history. Viruses were more frequently detected among AEx-inpatients <5 years (350/458 [76%]) than 5–17 years (305/496 [61%], P < 0.001). Most (615/655 [94%]) detections were of single viruses. The most frequent single virus detections were RV/EV (474/954 [50%]) and RSV (76/954 [8%]) but the frequency of each virus varied by season and age group (figure). Single RV/EVs were the most common virus detections in both seasons and all groups. Single RSV detections were prominent among <5 year olds in winter (40/185 [22%]). Among those with single RV/EV or RSV detections, 285/474 (60%) and 49/76 (64%) required supplemental oxygen, respectively (P = 0.676); median length of stay was 1 day (range: 0–45; IQR: 1–2) and 2 days (range: 0–6; IQR: 1–2.5), respectively (P < 0.001).

Conclusion

AEx-inpatients <5 years were more likely to have respiratory virus detections than those 5–17 years. Single RV/EVs formed the majority of virus detections throughout the surveillance period, regardless of age. RSV played a notable role in winter among patients <5 years. These findings could inform prevention or treatment strategies for virus-associated AEx.

Disclosures

All authors: No reported disclosures.

2324. Respiratory Viral Coinfection in a Birth Cohort of Infants in Rural Nepal

Background

Acute respiratory illnesses are a leading cause of global morbidity and mortality in children. Coinfection with multiple respiratory viruses is common. Although the effects of each virus have been studied individually, the effects of coinfection on disease severity or healthcare seeking are less well-understood.

Methods

A secondary analysis was performed of a maternal influenza vaccine trial conducted between 2011 and 2014 in rural southern Nepal. Prospective weekly active household-based surveillance of infants was conducted from birth to 180 days of age. Mid-nasal swabs were collected and tested for respiratory syncytial virus (RSV), rhinovirus, influenza, human metapneumovirus (HMPV), coronavirus, parainfluenza (HPIV), and bocavirus by RT–PCR. Coinfection was defined as the presence of two or more respiratory viruses simultaneously detected as part of the same illness episode. Maternal vaccination status, infant age, prematurity, and number of children under 5 in the household were adjusted for with multivariate logistic regression.

Results

Of 1,730 infants with a respiratory illness, 327 (19%) had at least two respiratory viruses detected on their primary illness episode. Coinfection status did not differ by maternal vaccination status, infant age, premature birth, and number of children under 5 in the household. Of 113 infants with influenza, 23 (20%) had coinfection. Of 214 infants with RSV, 87 (41%) had coinfection. Overall, infants with coinfection had increased occurrence of fever lasting 4 or more days overall (OR 1.4, 95% CI: 1.1, 2.0), and in the subset of infants with influenza (OR 5.8, 95% CI: 1.8, 18.7). Coinfection was not associated with seeking further care (OR 1.1, 95% CI: 0.8, 1.5) or pneumonia (OR 1.2, 95% CI: 1.0, 1.6).

Conclusion

A high proportion of infants experiencing their first respiratory illness had multiple viruses detected. Coinfection with influenza was associated with longer duration of fever compared with children with influenza alone, but was not associated with increased illness severity by other measures.

Disclosures

All authors: No reported disclosures.

2215. Diarrheal Illness as a Risk Factor for Subsequent Respiratory Infection Among Women and Infants in Nepal

Background

Globally, diarrheal and respiratory infections are responsible for nearly one-quarter of deaths in children under 5 years old. Historically these diseases have been studied separately; recent evidence suggests that preceding diarrheal disease may be a risk factor for subsequent respiratory illness. We sought to identify whether diarrhea was associated with subsequent respiratory illness in adult women and infants in Nepal.

Methods

We used data from a community-based, prospective randomized trial of maternal influenza immunization of pregnant women and their infants conducted in rural Nepal from 2011 to 2014. Diarrhea episodes were defined as at least three self-reported watery bowel movements per day for one or more days. Respiratory illness episodes were defined as the presence of fever with an additional respiratory symptom. Diarrhea and respiratory illness episodes were identified through longitudinal household-based weekly symptom surveillance. A case-crossover design was used to determine whether risk of respiratory infection was increased in the 30 days following a diarrhea episode compared with the 30 days prior.

Results

Of 3,693 women in the study and their 3,646 infants, 525 (14.2%) women experienced one or more episodes of diarrhea during pregnancy, 226 (9.4%) women experienced one or more episodes of diarrhea after pregnancy, and 342 (9.4%) infants had one or more episodes of diarrhea. The incidence of respiratory episodes during the exposure and control periods was approximately 2–5% in adults and 8–10% in infants. Preceding diarrhea was not significantly associated with respiratory infection in adult women or infants. There was a slight trend toward greater incidence of diarrhea during the exposure period among infants (Figure 1), but it was not statistically significant. These results held after a sensitivity analysis limiting follow-up time to 15 days before and after diarrhea episode.

Conclusion

In this study of pregnant and postpartum women and their infants in Nepal, diarrheal illness was not a significant risk factor for subsequent respiratory illness.

Disclosures

All authors: No reported disclosures.

95. Impact of Influenza-Like Illnesses on Academic and Work Performance on a College Campus

Background

Influenza-like illnesses are estimated to cause 500,000 hospitalizations and 50,000 deaths each year in the United States. The high-contact environment of a college campus makes students, faculty, and staff especially prone to respiratory illness, but the impact of these illnesses on academic and work performance is not well understood.

Methods

Between January 14 and April 3, 2019, the Seattle Flu Study enrolled participants with respiratory symptoms throughout the Seattle metropolitan area, including the University of Washington’s main campus. Individuals with at least two self-reported respiratory symptoms in the previous 7 days were eligible to enroll. Participants completed a questionnaire with questions about their medical history, current illness episode, and other behavioral characteristics; a corresponding mid-nasal swab was also collected. Influenza-like illness (ILI) was defined as self-reported fever with a cough and/or sore throat. Laboratory results are pending. Logistic regression was used to assess the association between ILI and work and academic outcomes, including missing class, missing work, performing poorly on an assignment or examination, and experiencing high interference on daily life.

Results

A total of 497 participants enrolled at the University of Washington. Participants had a median age of 22, and 61% were female. Of those with self-reported ILI, 27% reported smoking, 22% had traveled out of state, and 14% had traveled internationally in the month before enrollment. These characteristics did not differ between those with ILI and those with non-ILI. Having symptoms of ILI was associated with reports of missing work (OR 2.9; 95% CI: 1.9, 4.5), missing class (OR 3.4; 95% CI: 2.3, 5.2), performing poorly on assignments and exams (OR 1.8; 95% CI: 1.2, 2.6), and having high interference with daily life (OR 6.0; 95% CI: 3.8, 9.5) as compared with individuals with a non-ILI illness. These impacts were strongest during January and February.

Conclusion

A high prevalence of ILI was observed on campus. These symptoms were found to have a substantial impact on academic and occupational productivity. This demonstrates the need for greater illness prevention efforts on college campuses during influenza season.

Disclosures

All Authors: No reported Disclosures.

2759. Immunogenicity of Inactivated Influenza Vaccines Given Early vs. Late After Pediatric Allogeneic Hematopoietic Cell Transplantation

Background

Pediatric hematopoietic cell transplant (HCT) recipients often fail to have robust responses to influenza (flu) vaccine. We conducted a blinded phase II trial comparing high-dose (HD) trivalent inactivated vaccine (TIV) vs. standard dose (SD) quadrivalent inactivated vaccine (QIV).

Methods

Children 3–17 years old and 3–35 months post-allogeneic HCT were enrolled at 9 centers and randomized to either 2 doses of HD-TIV or SD-QIV during the 2016–2017 flu season. We compared immune responses by hemagglutination inhibition (HAI) from children 3–11 (early) vs. 12–35 (late) months (m) post-HCT to 3 common flu vaccine antigens, irrespective of vaccine type. HAI responses were evaluated at baseline (visit 1), 1 m post dose 1 (visit 2) and dose 2 (visit 3), and 7 m post dose 2 (visit 4). Geometric mean titers (GMT) were adjusted for baseline log-titer values.

Results

Thirty-one children, median age 11 (7–15) years, were enrolled; 17 (55%) were immunized early and 14 (45%) late. Over 50% of patients had a potentially seroprotective (≥1:40) HAI titer at baseline, with no significant difference post-vaccination between early and late subjects. Table 1 compares early vs late subjects with HAI seroconversion (4-fold HAI titer rise). Post dose 1, late subjects, compared with early, had higher rates of seroconversion to all influenza strains. Post dose 2, early subjects, compared with late, had increased seroconversion. Late subjects had higher GMTs for H1N1 post dose 1 and 2, H3N2 after dose 1, and strain B/VIC post dose 1 and 2 (Figure 1). Although immunogenicity waned throughout flu season, higher seroconversion rates and GMT to H3N2 and strain B/VIC were retained in late subjects.

Conclusion

Compared with subjects in early post-HCT group, late post-HCT subjects had better flu vaccine immune responses as noted by higher GMT and HAI seroconversion. However, 2 doses seemed more beneficial in the early post-HCT group. Future analyses are underway, including comparing immunogenicity of HD vs. SD flu vaccine.

Disclosures

Jennifer E. Schuster, MD, Satchel Health: Shareholder Flor M. Munoz, M.D, Biocryst: Grant/Research Support; CDC: Research Grant; Moderna: Other Financial or Material Support, Safety Monitoring Board Member/Chair; NIH: Research Grant; Novavax: Research Grant; UP to Date: Author and Editor - Royalties, Other Financial or Material Support.

2614. Demographic and Clinical Characteristics by Antiviral Prescription in Influenza-Positive Children who Presented to Seven US Emergency Departments

Background

Antiviral (AV) therapy is recommended for children < 2 years, hospitalized, or with underlying conditions (UC) and suspected influenza (flu). We sought to compare demographic and clinical characteristics by AV prescription in flu-positive children who presented to the emergency department (ED) and determine the percentage of AV prescription in these high-risk children.

Methods

Children < 18 years who presented with respiratory symptoms and/or fever at seven New Vaccine Surveillance Network sites were enrolled. We conducted interviews, obtained mid-turbinate nasal and/or throat swabs for molecular flu testing (results unknown to providers), and reviewed medical charts for AV prescription after presenting to the ED. These are preliminary data.

Results

From December 2016 to June 2018, 9,524 subjects were enrolled and tested for flu; 1,260 (13%) were flu-positive by research testing; 54% were male, median age was 41 months, and 23% were prescribed an AV. The frequency of AV prescription differed by study site (Figure 1). Among research-tested flu-positive patients, AV were prescribed to 25% of children < 2 years, 31% of children with UC, and 51% admitted to the hospital from the ED (Table 1). Of the 388 (31%) clinically-tested flu-positive patients, 52%, 66%, and 77% of the same high-risk groups were prescribed an AV, respectively.

Conclusion

AV prescriptions varied by study site and differences by race, ethnicity, and clinical presentation were noted. Clinical testing was associated with higher use of AV treatment in appropriate target patients. Efforts are needed to understand AV use patterns and improve prescription rates in recommended patients.

Disclosures

All authors: No reported disclosures.

2626. Rhinovirus in Children Presenting to the Emergency Department: Role of Viral Load in Disease Severity and Co-Infections

Background

Rhinovirus (RV) quantitation by reverse transcription-quantitative PCR is limited by variable amplification efficiency across genotypes. We used a precise viral quantitation method, reverse transcription-digital PCR (RT-dPCR), to characterize the role of viral load in clinical outcomes and in viral co-infections in children presenting to a tertiary hospital emergency department (ED).

Methods

Children < 18 years with respiratory symptoms for ≤ 14 days were enrolled from December 1, 2016 to December 31, 2018. Participants had nasal and throat specimens obtained and multiplex PCR testing with a commercial assay (FilmArray; bioMerieux). RV positive samples were quantified using RT-dPCR. Samples with sufficient viral load were sequenced at a 543 bp fragment of the RV VP4/VP2 region. RV species were assigned by comparison to RV sequences in GenBank using BLAST. Clinical data were collected into REDCap. T-tests were used to compare mean viral loads between groups.

Results

Of 1703 children enrolled in the ED, 697 were RV/enterovirus positive by FilmArray [median age 18 months (interquartile range 9–39 months)]. Of 590 subjects with viral load available, 276 (47%) were admitted to the hospital. Among RV mono-infections (N = 434), mean viral load did not differ between subjects admitted vs. discharged from the ED (7.03 log copies/mL for both, P = 0.97). Among admitted subjects with RV mono-infection, viral load also did not differ between subjects requiring supplemental oxygen vs. not (7.01 vs. 7.10 log copies/mL, P = 0.6). Subjects with viral co-infections had lower mean RV viral loads (6.31 log copies/mL) compared with those with RV only (7.03 log copies/mL; P < 0.001) (figure). Significantly different RV viral loads were seen with co-infections with respiratory syncytial virus (RSV), metapneumovirus (MPV) and parainfluenza (PIV), but not with influenza, adenovirus or coronavirus. In 525 sequenced samples (46% RV-A, 4% RV-B, 50% RV-C), viral load did not vary between RV viral species (P = 0.09).

Conclusion

Precise viral quantitation demonstrates children co-infected with RV and RSV, MPV or PIV have lower nasal viral loads than those with RV alone. Among RV mono-infections, RV viral load was not associated with admission or need for supplemental oxygen.

Disclosures

All authors: No reported disclosures.

1756. Role of Human bocavirus Respiratory Tract Infection in Hematopoietic Cell Transplant Recipients

Background

Limited data exist regarding the impact of human bocavirus (BoV) in hematopoietic cell transplant (HCT) recipients. We examined incidence and disease spectrum of BoV respiratory tract infection (RTI) in HCT recipients.

Methods

In a longitudinal surveillance study of viral RTIs among allogeneic HCT recipients, pre-HCT and weekly post-HCT nasal washes and symptom surveys were collected through day 100, then every 3 months, and whenever respiratory symptoms occurred through 1-year post-HCT. Samples were tested by multiplex semi-quantitative PCR for RSV, parainfluenza virus 1–4, influenza A/B, adenovirus, human metapneumovirus, rhinovirus, coronavirus, and BoV. Plasma samples from BoV+ subjects were analyzed by PCR. In addition, we conducted a retrospective review of HCT recipients with BoV detected in bronchoalveolar lavage or lung biopsy.

Results

Among 469 patients in the prospective cohort, 21 distinct BoV RTIs (3 pre-HCT and 18 post-HCT) were observed by 1-year post-HCT in 19 patients (median 42 years old, range 0–67) without apparent seasonality. BoV was more frequently detected in the latter half of the first 100 days post-HCT (Figure 1). The frequencies of respiratory symptoms in patients with BoV detected did not appear to be higher than those without any virus detected, with the exception of watery eyes (P < 0.01) (Figure 2). Univariable models among patients with BoV RTI post-HCT showed higher peak viral load in nasal samples (P = 0.04) and presence of respiratory copathogens (P = 0.03) were associated with presence of respiratory symptoms; however, BoV detection in plasma was not (P = 0.8). Retrospective review identified 6 allogeneic HCT recipients (range 1–64 years old) with BoV detected in lower respiratory tract specimens [incidence rate of 0.4% (9/2,385) per sample tested]. Although all 6 cases presented with hypoxemia, 4 had significant respiratory copathogens or concomitant conditions that contributed to respiratory compromise. No death was attributed mainly to BoV lower RTI.

Conclusion

BoV is infrequently detected in respiratory tract in HCT recipients. Our studies did not demonstrate convincing evidence that BoV is a significant pathogen in either upper or lower respiratory tracts. Watery eyes were associated with BoV detection.

Disclosures

All authors: No reported disclosures.

Singer M, Avadhanula V, McNeal M, Figueroa-Downing D, Prill MM, Whitaker BL, Payne DC, Lindstrom S, Thornburg NJ, Gerber SI, Langley G, Langley G. 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.

Hepatitis B Birth Dose: First Shot at Timely Early Childhood Vaccination

INTRODUCTION

Current U.S. recommendations state that newborns weighing ≥2,000 grams should receive a birth dose of hepatitis B vaccine, yet approximately one quarter do not receive this first dose as scheduled. The relationship between timely receipt of the first hepatitis B vaccine and other early childhood vaccines remains unclear.

METHODS

Washington State newborns (birth weight ≥2,000 grams) who received birth hospitalization care at an urban academic medical center between 2008 and 2013 were included. Multivariable logistic regression was used to assess whether hepatitis B vaccine receipt during the birth hospitalization was associated with completing the seven-vaccine series by 19 months, adjusting for select sociodemographic, clinical, and birth hospitalization characteristics. Analyses were conducted in 2017-2018.

RESULTS

Of the 9,080 study participants, 75.5% received hepatitis B vaccine during the birth hospitalization, and 53.6% completed the seven-vaccine series by 19 months. Overall, 60.0% of infants vaccinated against hepatitis B during the birth hospitalization completed the seven-vaccine series by 19 months compared with 33.8% of those who were unvaccinated at discharge (p<0.001). The odds of series completion were nearly 3 times higher among infants who received versus did not receive hepatitis B vaccine during the birth hospitalization (AOR=2.92, 95% CI=2.61, 3.26).

CONCLUSIONS

Infants who received hepatitis B vaccine during their birth hospitalization had higher odds of receiving all recommended vaccines by 19 months independent of other factors associated with vaccine receipt. Understanding the factors that influence this first parental vaccine decision and how hepatitis B vaccine delay or declination may affect subsequent vaccination requires further research.

Antiviral combination therapy for cytomegalovirus infection in high-risk infants

BACKGROUND

Cytomegalovirus (CMV) infection is a major risk factor for mortality in infants with severe combined immunodeficiency (SCID) and other profound immune defects. Specific antiviral therapy must be initiated early and aggressively because of the potential for antiviral resistance, rapid dissemination and poor transplant outcomes. Combination antiviral therapy is routinely administered for some viral infections, but the value of this approach for the treatment of CMV is unclear. Here we explore a strategy of initial combination therapy for high-risk infants with CMV infection.

METHODS

We reviewed medical records of infants ≤6 months of age hospitalized between 2007-2015 who received ganciclovir (GCV) or foscarnet (FOS) monotherapy or initial combination GCV + FOS for CMV disease. The combination therapy group consisted of severely immunocompromised infants being considered for haematopoietic cell transplantation (HCT).

RESULTS

Four patients received initial combination antiviral therapy and 26 patients received initial monotherapy during the study period. Combination antiviral recipients demonstrated initial improvement in viraemia and two of three who continued with this therapy survived the infection. Clinically significant resistance mutations did not emerge. Toxicity was common; neutropenia, thrombocytopenia and electrolyte abnormalities were the most frequent adverse events in both groups. Creatinine elevation was uncommon in both groups.

CONCLUSIONS

Combination GCV + FOS therapy may be a safe alternative to monotherapy in high-risk infants, especially those who are pre-transplant with primary immune deficiency syndromes and high viral loads.

Association of Rotavirus Vaccination With Inpatient and Emergency Department Visits Among Children Seeking Care for Acute Gastroenteritis, 2010-2016

IMPORTANCE

Rotavirus vaccines have been recommended for universal US infant immunization for more than 10 years, and understanding their effectiveness is key to the continued success of the US rotavirus vaccine immunization program.

OBJECTIVE

To assess the association of RotaTeq (RV5) and Rotarix (RV1) with inpatient and emergency department (ED) visits for rotavirus infection.

DESIGN, SETTING, AND PARTICIPANTS

This case-control vaccine effectiveness study was performed at inpatient and ED clinical settings in 7 US pediatric medical institutions from November 1, 2009, through June 30, 2016. Children younger than 5 years seeking medical care for acute gastroenteritis were enrolled. Clinical and epidemiologic data, vaccination verification, and results of stool sample tests for laboratory-confirmed rotavirus were collected. Data were analyzed from November 1, 2009, through June 30, 2016.

MAIN OUTCOMES AND MEASURES

Rotavirus vaccine effectiveness for preventing rotavirus-associated inpatient and ED visits over time for each licensed vaccine, stratified by clinical severity and age.

RESULTS

Among the 10 813 children included (5927 boys [54.8%] and 4886 girls [45.2%]; median [range] age, 21 [8-59] months), RV5 and RV1 analyses found that compared with controls, rotavirus-positive cases were more often white (RV5, 535 [62.2%] vs 3310 [57.7%]; RV1, 163 [43.1%] vs 864 [35.1%]), privately insured (RV5, 620 [72.1%] vs 4388 [76.5%]; RV1, 305 [80.7%] vs 2140 [87.0%]), and older (median [range] age for RV5, 26 [8-59] months vs 21 [8-59] months; median [range] age for RV1, 22 [8-59] months vs 19 [8-59] months) but did not differ by sex. Among 1193 rotavirus-positive cases and 9620 rotavirus-negative controls, at least 1 dose of any rotavirus vaccine was 82% (95% CI, 77%-86%) protective against rotavirus-associated inpatient visits and 75% (95% CI, 71%-79%) protective against rotavirus-associated ED visits. No statistically significant difference during this 7-year period was observed for either rotavirus vaccine. Vaccine effectiveness against inpatient and ED visits was 81% (95% CI, 78%-84%) for RV5 (3 doses) and 78% (95% CI, 72%-82%) for RV1 (2 doses) among the study population. A mixed course of both vaccines provided 86% (95% CI, 74%-93%) protection. Rotavirus patients who were not vaccinated had severe infections 4 times more often than those who were vaccinated (74 of 426 [17.4%] vs 28 of 605 [4.6%]; P < .001), and any dose of rotavirus vaccine was 65% (95% CI, 56%-73%) effective against mild infections, 81% (95% CI, 76%-84%) against moderate infections, and 91% (95% CI, 85%-95%) against severe infections.

CONCLUSIONS AND RELEVANCE

Evidence from this large postlicensure study of rotavirus vaccine performance in the United States from 2010 to 2016 suggests that RV5 and RV1 rotavirus vaccines continue to perform well, particularly in preventing inpatient visits and severe infections and among younger children.