Impact of Timing of Influenza Vaccination in Pregnancy on Transplacental Antibody Transfer, Influenza Incidence, and Birth Outcomes: A Randomized Trial in Rural Nepal

Background

Maternal influenza vaccination protects mothers and their infants in low resource settings, but little is known about whether the protection varies by gestational age at vaccination.

Methods

Women of childbearing age in rural southern Nepal were surveilled for pregnancy, consented and randomized to receive maternal influenza vaccination or placebo, with randomization stratified on gestational age (17-25 or 26-34 weeks). Enrollment occurred in 2 annual cohorts, and vaccinations occurred from April 2011 through September 2013.

Results

In sum, 3693 women consented and enrolled, resulting in 3646 live births. Although cord blood antibody titers and the rise in maternal titers were generally greater when women were vaccinated later in pregnancy, this was not statistically significant. The incidence risk ratio (IRR) for maternal influenza in pregnancy through 6 months postpartum was 0.62 (95% confidence interval [CI]: 0.35, 1.10) for those vaccinated 17-25 weeks gestation and 0.89 (95% CI: 0.39, 2.00) for those 26-34 weeks. Infant influenza IRRs were 0.73 (95% CI: 0.51, 1.05) for those whose mothers were vaccinated earlier in gestation, and 0.63 (95% CI: 0.37, 1.08) for those later. Relative risks (RR) for low birthweight were 0.83 (95% CI: 0.71, 0.98) and 0.90 (95% CI: 0.72, 1.12) for 17-25 and 26-34 weeks gestation at vaccination, respectively. IRRs did not differ for small-for-gestational age or preterm. No RRs were statistically different by timing of vaccine receipt.

Conclusions

Vaccine efficacy did not vary by gestational age at vaccination, making maternal influenza immunization programs easier to implement where women present for care late in pregnancy.

Clinical Trials Registration

NCT01034254.

Enterovirus D-68 in children presenting for acute care in the hospital setting

BACKGROUND

Severe respiratory disease associated with enterovirus D68 (EV-D68) has been reported in hospitalized pediatric patients. Virologic and clinical characteristics of EV-D68 infections exclusively in patients presenting to a hospital Emergency Department (ED) or urgent care have not been well defined.

METHODS

Mid-nasal swabs from pediatric patients with respiratory symptoms presenting to the ED or urgent care were evaluated using a commercial multiplex PCR platform. Specimens positive for rhinovirus/enterovirus (HRV/EV) were subsequently tested using real-time reverse-transcriptase PCR for EV-D68. The PCR cycle threshold (CT) was used as a viral load proxy. Clinical outcomes were compared between patients with EV-D68 and patients without EV-D68 who tested positive for HRV/EV.

RESULTS

From August to December 2014, 511 swabs from patients with HRV/EV were available. EV-D68 was detected in 170 (33%) HRV/EV-positive samples. In multivariable models adjusted for age and underlying asthma, patients with EV-D68 were more likely to require hospitalization for respiratory reasons (odds ratio (OR): 3.11, CI: 1.85-5.25), require respiratory support (OR: 1.69, CI: 1.09-2.62), have confirmed/probable lower respiratory tract infection (LRTI; OR: 3.78, CI: 2.03-7.04), and require continuous albuterol or steroids (OR: 3.91, CI: 2.22-6.88 and OR: 4.73, CI: 2.65-8.46, respectively). Higher EV-D68 viral load was associated with need for respiratory support and LRTI in multivariate models.

CONCLUSIONS

Among pediatric patients presenting to the ED or urgent care, EV-D68 causes more severe disease than non-EV-D68 HRV/EV independent of underlying asthma. High viral load was associated with worse clinical outcomes. Rapid and quantitative viral testing may help identify and risk stratify patients.

Maternal immunization

Pregnant women, neonates, and infants are at higher risk for severe infections due to vaccine-preventable diseases. Very young infants rarely respond well to vaccination due to poor immunogenicity and interference from maternal antibody. Maternal immunization protects the mother and fetus from disease and protects the infant through transplacental antibody transfer through the first 6 months of life. Currently, immunizations routinely recommended during pregnancy include inactivated influenza, tetanus toxoid, and acellular pertussis vaccines. Promising maternal vaccine candidates in development include a group B streptococcus vaccine and a respiratory syncytial virus vaccine. Birth Defects Research 109:379-386, 2017. © 2017 Wiley Periodicals, Inc.

Antibiotic Exposure Prior to Respiratory Viral Infection Is Associated with Progression to Lower Respiratory Tract Disease in Allogeneic Hematopoietic Cell Transplant Recipients

Recent publications note an association between antibiotic exposure and respiratory viral infections (RVIs). Antibiotics affect microbiota and impair immune response against RVIs in mice, and low microbiome diversity is associated with pulmonary complications including viral lower respiratory tract disease (LRTD) in hematopoietic cell transplantation (HCT) recipients. In this study, we examined whether antibiotic exposure was associated with increased risk of disease progression in RVIs post-transplantation. We analyzed patients who underwent allogeneic HCT (June 2008 to February 2016) and had their first RVI due to parainfluenza virus (PIV), respiratory syncytial virus (RSV), or human metapneumovirus (MPV) during the initial 100 days post-transplantation. Antibiotic exposure in the 3 weeks before RVI onset was defined as (1) use of specific antibiotics versus none of these antibiotics and (2) number of antibiotic-days. Cox proportional hazards models were used to examine associations between antibiotic exposures and risk of viral disease progression to proven/probable/possible LRTD. Ninety HCT recipients (84 adults, 6 children) fulfilled study criteria; 33 progressed to LRTD. The number of antibiotic-days was associated with progression to LRTD after adjusting for neutropenia, steroid use, and either lymphopenia (hazard ratio, 1.41 [95% confidence interval, 1.04 to 1.92], P = .027) or monocytopenia (hazard ratio, 1.46 [95% confidence interval, 1.11 to 1.91], P = .006). Specific antibiotic classes was not associated with the outcome. Cumulative antibiotic exposure immediately before RVI onset is a risk factor for disease progression following PIV, RSV, and MPV infections post-transplantation. Larger cohort studies are needed to determine the impact of specific antibiotics or antibiotic classes on disease severity.

Human Metapneumovirus and Other Respiratory Viral Infections during Pregnancy and Birth, Nepal

Human metapneumovirus (HMPV) is a respiratory virus that can cause severe lower respiratory tract disease and even death, primarily in young children. The incidence and characteristics of HMPV have not been well described in pregnant women. As part of a trial of maternal influenza immunization in rural southern Nepal, we conducted prospective, longitudinal, home-based active surveillance for febrile respiratory illness during pregnancy through 6 months postpartum. During 2011-2014, HMPV was detected in 55 of 3,693 women (16.4 cases/1,000 person-years). Twenty-five women were infected with HMPV during pregnancy, compared with 98 pregnant women who contracted rhinovirus and 7 who contracted respiratory syncytial virus. Women with HMPV during pregnancy had an increased risk of giving birth to infants who were small for gestational age. An intervention to reduce HMPV febrile respiratory illness in pregnant women may have the potential to decrease risk of adverse birth outcomes in developing countries.

A Multicenter Consortium to Define the Epidemiology and Outcomes of Pediatric Solid Organ Transplant Recipients With Inpatient Respiratory Virus Infection

BACKGROUND

Respiratory virus infection (RVI) in pediatric solid organ transplant (SOT) recipients poses a significant risk; however, the epidemiology and effects of an RVI after pediatric SOT in the era of current molecular diagnostic assays are unclear.

METHODS

A retrospective observational cohort of pediatric SOT recipients (January 2010 to June 2013) was assembled from 9 US pediatric transplant centers. Charts were reviewed for RVI events associated with hospitalization within 1 year after the transplant. An RVI diagnosis required respiratory symptoms and detection of a virus (ie, human rhinovirus/enterovirus, human metapneumovirus, influenza virus, parainfluenza virus, coronavirus, and/or respiratory syncytial virus). The incidence of RVI was calculated, and the association of baseline SOT factors with subsequent pulmonary complications and death was assessed.

RESULTS

Of 1096 pediatric SOT recipients (448 liver, 289 kidney, 251 heart, 66 lung, 42 intestine/multivisceral), 159 (14.5%) developed RVI associated with hospitalization within 12 months after their transplant. RVI occurred at the highest rates in intestine/abdominal multivisceral (38%), thoracic (heart/lung) (18.6%), and liver (15.6%) transplant recipients and a lower rate in kidney (5.5%) transplant recipients. RVI was associated with younger median age at transplant (1.72 vs 7.89 years; P < .001) and among liver or kidney transplant recipients with the receipt of a deceased-donor graft compared to a living donor (P = .01). The all-cause and attributable case-fatality rates within 3 months of RVI onset were 4% and 0%, respectively. Multivariable logistic regression models revealed that age was independently associated with increased risk for a pulmonary complication (odds ratio, 1.24 [95% confidence interval, 1.02-1.51]) and that receipt of an intestine/multivisceral transplant was associated with increased risk of all-cause death (odds ratio, 24.54 [95% confidence interval, 1.69-327.96]).

CONCLUSIONS

In this study, hospital-associated RVI was common in the first year after pediatric SOT and associated with younger age at transplant. All-cause death after RVI was rare, and no definitive attributable death occurred.

Identifying Gaps in Respiratory Syncytial Virus Disease Epidemiology in the United States Prior to the Introduction of Vaccines

Respiratory syncytial virus (RSV) causes lower respiratory tract illness frequently. No effective antivirals or vaccines for RSV are approved for use in the United States; however, there are at least 50 vaccines and monoclonal antibody products in development, with those targeting older adults and pregnant women (to protect young infants) in phase 2 and 3 clinical trials. Unanswered questions regarding RSV epidemiology need to be identified and addressed prior to RSV vaccine introduction to guide the measurement of impact and future recommendations. The Centers for Disease Control and Prevention (CDC) convened a technical consultation to gather input from external subject matter experts on their individual perspectives regarding evidence gaps in current RSV epidemiology in the United States, potential studies and surveillance platforms needed to fill these gaps, and prioritizing efforts. Participants articulated their individual views, and CDC staff synthesized individuals' input into this report.

Characteristics and Outcomes of Coronavirus Infection in Children: The Role of Viral Factors and an Immunocompromised State

BACKGROUND

Immunocompromised children might be predisposed to serious infections from human coronaviruses (HCoVs), including strains OC43, NL63, HKU1, and 229E; however, the virologic and clinical features of HCoV infection in immunocompromised children have not been compared to those in nonimmunocompromised children.

METHODS

We retrospectively analyzed a cohort of children who presented to Seattle Children's Hospital and in whom HCoV was detected by a multiplex respiratory polymerase chain reaction assay of a nasal sample between October 2012 and March 2016. Lower respiratory tract disease (LRTD) was defined as possible or definite infiltrate seen in chest imaging, need for oxygen, or abnormal lung examination in conjunction with a physician diagnosis of LRTD. We used logistic regression modeling to evaluate risk factors for LRTD and LRTD that necessitated oxygen use (severe LRTD), including an immunocompromised state, in children with HCoV infection.

RESULTS

The median ages of 85 immunocompromised and 1152 nonimmunocompromised children with HCoV infection were 6.3 and 1.6 years, respectively. The prevalence of LRTD and of severe LRTD did not differ greatly between the immunocompromised and nonimmunocompromised patients (22% vs 26% [LRTD] and 15% vs 11% [severe LRTD], respectively); however, in a multivariable model, an immunocompromised state was associated with an increased likelihood of severe LRTD (adjusted odds ratio, 2.5 [95% confidence interval, 1.2-4.9]; P = .01). Younger age, having an underlying pulmonary disorder, and the presence of respiratory syncytial virus were also associated with LRTD or severe LRTD in multivariable models. The risks of LRTD or severe LRTD did not differ among the children with different HCoV strains.

CONCLUSIONS

The presence of a copathogen and host factors, including an immunocompromised state, were associated with increased risk for severe LRTD. Recognizing risk factors for severe respiratory illness might assist in risk stratification.

Clinical Significance of Human Coronavirus in Bronchoalveolar Lavage Samples From Hematopoietic Cell Transplant Recipients and Patients With Hematologic Malignancies

Background.

The possible role of human coronavirus (HCoV) in lower respiratory tract disease (LRTD) in hematopoietic cell transplant (HCT) recipients and patients with hematologic malignancies (HM) has not been well studied.

Methods.

We conducted a retrospective review of HCT/HM patients with HCoV detected in bronchoalveolar lavage (BAL). HCoV strains were identified in BAL samples using strain-specific polymerase chain reaction. Mortality rates were compared among HCT recipients with LRTD caused by HCoV, respiratory syncytial virus (RSV), influenza virus, or parainfluenza virus (PIV) by multivariable Cox regression analysis.

Results.

We identified 35 patients (37 episodes) with HCoV LRTD. Among 23 available BAL samples, 48% were strain OC43, 22% were NL63, 17% were 229E, and 13% were HKU1. Overall, 21 patients (60%) required oxygen therapy at diagnosis and 19 (54%) died within 90 days of diagnosis. Respiratory copathogens were detected in 21 episodes (57%), including viruses (n = 12), fungi (n = 10), and bacteria (n = 8). Mortality rates were not different between patients with and without copathogens (P = .65). In multivariable models, mortality associated with HCoV LRTD was similar to that seen with RSV, influenza, and PIV LRTD in HCT recipients (adjusted hazard ratio, 1.34 [95% confidence interval, .66–2.71], P = .41 vs RSV, adjusted for cell source, cytopenia, copathogens, oxygen use, and steroid use).

Conclusions.

HCoV LRTD in patients with HCT or HM is associated with high rates of oxygen use and mortality. Mortality associated with HCoV LRTD in HCT recipients appears to be similar to that seen with RSV, influenza virus, and PIV.

Risk of Rotavirus Nosocomial Spread After Inpatient Pentavalent Rotavirus Vaccination

BACKGROUND

Infants born prematurely or with underlying conditions are at increased risk of severe rotavirus disease and associated complications. Given the theoretical risk of nosocomial transmission of vaccine-type rotavirus, rotavirus vaccination is recommended for infants at or after discharge from neonatal care settings. Because the first dose should be administered by 104 days of age, some infants may be age-ineligible for vaccination if delayed until discharge.

METHODS

This prospective cohort included infants admitted to an urban academic medical center between birth and 104 days who received care in intensive care settings. Pentavalent human-bovine reassortant rotavirus vaccine (RV5) was used, per routine clinical care. Stool specimens were collected weekly (February 2013-April 2014) and analyzed for rotavirus strains using real-time reverse transcription-polymerase chain reaction. Demographic and vaccine data were collected. RV5 safety was not assessed.

RESULTS

Of 385 study infants, 127 were age-eligible for routine vaccinations during hospitalization. At discharge, 32.7% were up-to-date for rotavirus vaccination, compared with 82.7% for other vaccinations. Of rotavirus-unvaccinated infants, 42.6% were discharged at age >104 days and thus vaccination-ineligible. Of 1192 stool specimens collected, rotavirus was detected in 13 (1.1%): 1 wild-type strain from an unvaccinated infant; 12 vaccine-type strains from 9 RV5-vaccinated infants. No vaccine-type rotavirus cases were observed among unvaccinated infants (incidence rate: 0.0 [95% confidence interval: 0.0-1.5] cases per 1000 patient days at risk).

CONCLUSIONS

These data suggest that delaying rotavirus vaccination until discharge from the hospital could lead to missed vaccination opportunities and may be unnecessary in institutions using RV5 with comparable infection control standards.

Supplemental Oxygen-Free Days in Hematopoietic Cell Transplant Recipients With Respiratory Syncytial Virus

Background

Clinically meaningful endpoints for respiratory syncytial virus (RSV) treatment trials are lacking for hematopoietic cell transplant (HCT) recipients. We evaluated supplemental oxygen use among HCT recipients with RSV infection.

Methods

Subjects were grouped according to the presence of upper respiratory tract infection (URTI) without lower respiratory tract infection (LRTI), URTI progressing to LRTI, and LRTI at presentation. LRTI was defined as a positive lower respiratory tract sample with or without radiographic abnormality (defined as proven or probable LRTI, respectively) or a positive upper respiratory tract sample with radiographic abnormality (possible LRTI). Supplemental oxygen–free days were defined as any day while alive after diagnosis of RSV infection during which ≤2 L of supplemental oxygen per minute was received.

Results

Among 230 patients, supplemental oxygen use by day 28 after the first diagnosis of RSV infection was lowest in patients presenting with URTI (31 of 197 [16%]). Supplemental oxygen use was lower in patients with possible LRTI (12 of 45 [27%]) than in those with proven/probable LRTI (29 of 42 [69%]). Patients presenting with proven/probable LRTI had a median of 16 fewer supplemental oxygen–free days than those presenting with URTI (P < .0001). Death only occurred among patients with proven/probable LRTI (11 of 42 [26%]).

Conclusions

Confirmation of RSV infection in the lower respiratory tract provides prognostic information that may help prioritize therapies. Supplemental oxygen–free days as a clinical endpoint may allow smaller sample sizes for trials evaluating RSV antivirals.

Nutritional status of infants at six months of age following maternal influenza immunization: A randomized placebo-controlled trial in rural Nepal

BACKGROUND

Maternal influenza vaccination has increased birth weight in two randomized trials in South Asia but the impact on infant growth is unknown.

METHODS

A randomized placebo-controlled trial of year round maternal influenza immunization was conducted in two annual cohorts in Sarlahi District, southern plains of Nepal, from April 2011 through April 2014. Infants born to women enrolled in the trial had weight, length, and head circumference measured at birth and 6 months of age. The study was powered for the 3 primary trial outcomes but not for stunting and wasting at 6 months of age.

RESULTS

3693 women received placebo or influenza vaccine between 17 and 34 weeks gestation, resulting in 3646 live births. About 72% of infants who survived had weight and length measurements between 150 and 210 days of age. Prevalence of stunting (<-2 Z scores length-for-age) was 14.8% in the placebo and 13.6% in the vaccine groups, respectively. Stunting < -3 Z scores was 3.2% versus 2.0% in placebo versus vaccine groups (RR: 0.64 (95% CI: 0.39, 1.04)). Wasting (< -2 Z scores weight for length) was 10.3% versus 11.0% for placebo versus vaccine groups. Severe wasting (< -3 Z scores weight for length) was 3.8% for placebo versus 2.6% for vaccine (RR: 0.69 (95% CI: 0.44, 1.07)). The impact of flu vaccine on wasting was greater in cohort 2 than in cohort 1, (RR: 0.66 (0.44, 0.99) for any wasting), and RR: 0.45 (0.19, 1.09) for severe wasting. This corresponded to a larger impact on birth weight and a better vaccine match with circulating viruses in cohort 2.

CONCLUSIONS

Although maternal immunization reduced low birth weight by 15%, only wasting at 6 months in the 2nd cohort was statistically significantly difference. However, the study was underpowered to detect reductions of public health importance.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT01034254).

Renal Toxicity in Pediatric Patients Receiving Cidofovir for the Treatment of Adenovirus Infection

Treatment options for adenovirus infection in immunocompromised children are limited. Nephrotoxicity has been associated with cidofovir use, but the rate of cidofovir-associated nephrotoxicity in pediatric patients is unclear. In a retrospective review of patients with adenovirus infection treated with cidofovir, neonates (n = 5) had higher viral loads and shorter times to renal insufficiency than older children (n = 24). Higher weekly doses of cidofovir were associated with greater increases in creatinine levels. Of 29 courses of cidofovir, 9 were complicated by acute kidney injury; in these children, mortality was high. Cidofovir dosing in children needs to be optimized, and other therapeutic alternatives should be developed.

Impact of maternal vaccination timing and influenza virus circulation on birth outcomes in rural Nepal

OBJECTIVE

To describe the effect of maternal vaccination on birth outcomes in rural Nepal, modified by timing of vaccination in pregnancy and influenza virus activity.

METHODS

A secondary analysis was conducted using data from two annual cohorts of a randomized controlled trial. A total of 3693 pregnant women from Sarlahi District were enrolled between April 25, 2011, and September 9, 2013. All participants were aged 15-40 years and received a trivalent inactivated influenza vaccine or placebo. The outcome measures included birth weight, pregnancy length, low birth weight (<2500 g), preterm birth, and small-for-gestational-age birth.

RESULTS

Data were available on birth weight for 2741 births and on pregnancy length for 3623 births. Maternal vaccination increased mean birthweight by 42 g (95% confidence interval [CI] 8-76). The magnitude of this increase varied by season but was greatest among pregnancies with high influenza virus circulation during the third trimester. Birth weight increased by 111 g (95% CI -51 to 273) when 75%-100% of a pregnancy's third trimester had high influenza virus circulation versus 38 g (95% CI -6 to 81) when 0%-25% of a pregnancy's third trimester had high influenza virus circulation. However, these results were nonsignificant.

CONCLUSION

Seasonal maternal influenza vaccination in rural Nepal increased birth weight; the magnitude appeared larger during periods of high influenza virus circulation. CLINICALTRIALS.GOV: NCT01034254.

Prolonged Shedding of Human Coronavirus in Hematopoietic Cell Transplant Recipients: Risk Factors and Viral Genome Evolution

Background

Recent data suggest that human coronavirus (HCoV) pneumonia is associated with significant mortality in hematopoietic cell transplant (HCT) recipients. Investigation of risk factors for prolonged shedding and intrahost genome evolution may provide critical information for development of novel therapeutics.

Methods

We retrospectively reviewed HCT recipients with HCoV detected in nasal samples by polymerase chain reaction (PCR). HCoV strains were identified using strain-specific PCR. Shedding duration was defined as time between first positive and first negative sample. Logistic regression analyses were performed to evaluate factors for prolonged shedding (≥21 days). Metagenomic next-generation sequencing (mNGS) was conducted when ≥4 samples with cycle threshold values of <28 were available.

Results

Seventeen of 44 patients had prolonged shedding. Among 31 available samples, 35% were OC43, 32% were NL63, 19% were HKU1, and 13% were 229E; median shedding duration was similar between strains (P = .79). Bivariable logistic regression analyses suggested that high viral load, receipt of high-dose steroids, and myeloablative conditioning were associated with prolonged shedding. mNGS among 5 subjects showed single-nucleotide polymorphisms from OC43 and NL63 starting 1 month following onset of shedding.

Conclusions

High viral load, high-dose steroids, and myeloablative conditioning were associated with prolonged shedding of HCoV in HCT recipients. Genome changes were consistent with the expected molecular clock of HCoV.

Trainee Needs in Pediatric Transplant Infectious Diseases Education

BACKGROUND

Pediatric transplant infectious diseases (PTID) is emerging as an area of expertise within pediatric infectious diseases. Although guidelines for training in PTID have been published, no prior national survey has been conducted to identify trainee-described needs for instruction in PTID.

METHODS

A survey was designed through collaboration between the American Society of Transplantation and the Pediatric Infectious Diseases Society, to assess trainee exposure, self-knowledge, and self-competency in PTID.

RESULTS

Sixty of 169 trainees replied (response rate 35%) with 93% of respondents from centers that performed transplants. Eighty-two percent of trainees were unaware of the recommended curriculum for PTID. Although a majority of trainees (78%) indicated they had received structured teaching in PTID, most (>50%) ranked their knowledge in donor selection, donor-derived infections, and candidate risk assessment as poor or fair. A majority (>50%) also reported their competency in areas regarding pre- and posttransplant guidance as poor or fair. Trainees identified the following strategies to augment their PTID training: additional rotations, teaching by experts, case-based learning, and a reference guide.

CONCLUSIONS

This survey highlights significant trainee-identified gaps in PTID knowledge and competency. Limitations include low survey response rate but appears weighted towards centers with transplantation. Suggested strategies can inform the development of learner-specific initiatives and curriculum in PTID.

Parallel evolution of influenza across multiple spatiotemporal scales

Viral variants that arise in the global influenza population begin as de novo mutations in single infected hosts, but the evolutionary dynamics that transform within-host variation to global genetic diversity are poorly understood. Here, we demonstrate that influenza evolution within infected humans recapitulates many evolutionary dynamics observed at the global scale. We deep-sequence longitudinal samples from four immunocompromised patients with long-term H3N2 influenza infections. We find parallel evolution across three scales: within individual patients, in different patients in our study, and in the global influenza population. In hemagglutinin, a small set of mutations arises independently in multiple patients. These same mutations emerge repeatedly within single patients and compete with one another, providing a vivid clinical example of clonal interference. Many of these recurrent within-host mutations also reach a high global frequency in the decade following the patient infections. Our results demonstrate surprising concordance in evolutionary dynamics across multiple spatiotemporal scales.

Rule-Out Outbreak: 24-Hour Metagenomic Next-Generation Sequencing for Characterizing Respiratory Virus Source for Infection Prevention

BACKGROUND.

Metagenomic next-generation sequencing (mNGS) has been used to uncover unusual causes of infectious diseases but has not been used routinely for the investigation of putative nosocomial outbreaks. Here, we describe the use of mNGS during investigation of a cluster of human rhinovirus (HRV)-positive infections on a high-risk pulmonary ward.

METHODS.

We performed mNGS on 6 midnasal turbinate swabs from 4 case-patients and 10 swabs from 9 control outpatients that tested positive for enterovirus/rhinovirus by the FilmArray system.

RESULTS.

HRV reads were recovered in 15 (94%) of the 16 samples sequenced. Phylogenetic analysis of HRV whole genomes from the 4 case-patients and 5 outpatient controls along with partial genomes from additional outpatient controls revealed that isolates from the case-patients were not directly related and that the 2 closest case HRV genomes had an estimated time to most recent common ancestor of 172 years. Our turnaround time from receipt of the sample to phylogenetic analysis was 24 hours.

CONCLUSIONS.

We found the use of mNGS downstream of a rapid polymerase chain reaction respiratory panel during an investigation of 4 hospital-acquired rhinovirus infections to rapidly dispel concern of a single-source transmission event.

Year-round influenza immunisation during pregnancy in Nepal: a phase 4, randomised, placebo-controlled trial

BACKGROUND

Influenza immunisation during pregnancy is recommended but not widely implemented in some low-income regions. We assessed the safety and efficacy in mothers and infants of year-round maternal influenza immunisation in Nepal, where influenza viruses circulate throughout the year.

METHODS

In this phase 4, randomised, placebo-controlled trial, we enrolled two consecutive sequential annual cohorts of pregnant women from the Sarlahi district in southern Nepal. We randomised mothers 1:1 to receive seasonally recommended trivalent inactivated influenza vaccine or saline placebo in blocks of eight, stratified by gestational age at enrolment (17-25 weeks vs 26-34 weeks). Women were eligible if they were married, 15-40 years of age, 17-34 weeks' gestation at enrolment, and had not previously received any influenza vaccine that season. We collected serum samples before and after immunisation, and cord blood from a subset of women and infants. Staff masked to allocation made home visits every week from enrolment to 6 months after delivery. Midnasal swabs for respiratory virus PCR testing were collected during maternal acute febrile respiratory infections, and from infants with any respiratory symptom. We assessed vaccine immunogenicity, safety, and three primary outcomes: the incidence of maternal influenza-like illness in pregnancy and 0-180 days postpartum, the incidence of low birthweight (<2500 g), and the incidence of laboratory-confirmed infant influenza disease from 0 to 180 days. This trial is registered with ClinicalTrials.gov, number NCT01034254.

FINDINGS

From April 25, 2011, to Sept 9, 2013, we enrolled 3693 women in two cohorts of 2090 (1041 assigned to placebo and 1049 to vaccine) and 1603 (805 assigned to placebo and 798 to vaccine), with 3646 liveborn infants (cohort 1, 999 in placebo group and 1010 in vaccine group; cohort 2, 805 in placebo group and 798 in vaccine group). Immunisation reduced maternal febrile influenza-like illness with an overall efficacy of 19% (95% CI 1 to 34) in the combined cohorts; 9% efficacy (-16 to 29) in the first cohort, and 36% efficacy (9 to 55) in the second cohort. For laboratory-confirmed influenza infections in infants aged 0-6 months, immunisation had an overall efficacy for the combined cohorts of 30% (95% CI 5 to 48); in the first cohort, the efficacy was 16% (-19 to 41), and in the second cohort it was 60% (26 to 88). Maternal immunisation reduced the rates of low birthweight by 15% (95% CI 3-25) in both cohorts combined. The rate of small for gestational age infants was not modified by immunisation. The number of adverse events was similar regardless of immunisation status. Miscarriage occurred in three (0·2%) participants in the placebo group versus five (0·3%) in the vaccine group, stillbirth occurred in 31 (1·7%) versus 33 (1·8%), and congenital defects occurred in 18 (1·0%) versus 20 (1·1%). Five women died in the placebo group and three died in the vaccine group. The number of infant deaths at age 0-6 months was similar in each group (50 in the placebo group and 61 in the vaccine group). No serious adverse events were associated with receipt of immunisation.

INTERPRETATION

Year-round maternal influenza immunisation significantly reduced maternal influenza-like illness, influenza in infants, and low birthweight over the entire course of the study, indicating the strategy could be useful in subtropical regions.

FUNDING

Bill & Melinda Gates Foundation.

Disposable Autonomous Device for Swab-to-Result Diagnosis of Influenza

A prototype of a self-contained, automated, disposable device for chemically amplified protein-based detection of influenza virus from nasal swab specimens was developed and evaluated in a clinical setting. The device required only simple specimen manipulation without any dedicated instrumentation or specialized training by the operator for interpretation. The device was based on a sandwich immunoassay for influenza virus nucleoprotein; it used an enzyme-labeled antibody and a chromogenic substrate to provide an amplified visible signal, in a two-dimensional paper network format. All reagents were stored within the device. Device performance was assessed at Seattle Children's Hospital; clinical staff collected nasal swab samples from 25 patients and then operated test devices on site to detect influenza A and B in those specimens. The total test time from device initiation to result was approximately 35 min. Device performance for influenza A detection was ∼70% accurate using in-house qRT-PCR influenza A as a gold-standard comparison. The ratio of valid to total completed device runs yielded a success rate of 92%, and the negative predictive value for both the influenza A and B assay was 81%. The ability to diagnose respiratory infections rapidly and close to the patient was well received by hospital staff, inspiring further optimization of device function.

Febrile Rhinovirus Illness During Pregnancy Is Associated With Low Birth Weight in Nepal

Background

Adverse birth outcomes, including low birth weight (LBW), defined as <2500 grams, small-for-gestational-age (SGA), and prematurity, contribute to 60%–80% of infant mortality worldwide and may be related to infections during pregnancy. The aim of this study was to assess whether febrile human rhinovirus (HRV) illness is associated with adverse birth outcomes.

Methods

Active household-based weekly surveillance was performed for respiratory illness episodes in pregnant women as part of a community-based, prospective, randomized trial of maternal influenza immunization in rural Nepal. Rhinovirus (HRV) febrile illness episodes were defined as fever plus cough, sore throat, runny nose, and/or myalgia with HRV detected on mid-nasal swab. Multivariate regression analysis evaluated the association between febrile HRV respiratory illness and adverse birth outcomes.

Results

Overall, 96 (3%) of 3693 pregnant women had HRV-positive febrile respiratory illnesses. Infants born to pregnant women with HRV febrile illness had a 1.6-fold increased risk of being LBW compared with those with non-HRV febrile illness (28 of 96 [38%] vs 109 of 458 [24%]; relative risk [RR], 1.6; 95% confidence interval [CI], 1.1–2.3). No difference in risk of LBW was observed between infants born to mothers with non-HRV febrile respiratory illness and those without respiratory illness during pregnancy (109 of 458 [24%] vs 552 of 2220 [25%], respectively; RR, 1.0; 95% CI, 0.8–1.2).

Conclusions

Febrile illness due to rhinovirus during pregnancy was associated with increased risk of LBW in a rural South Asian population. Interventions to reduce the burden of febrile respiratory illness due to rhinovirus during pregnancy may have a significant impact on LBW and subsequent infant mortality.