Influenza outbreaks are associated with substantial morbidity, mortality and economic burden. Next generation antivirals are needed to treat seasonal infections and prepare against zoonotic spillover of avian influenza viruses with pandemic potential. Having previously identified oral efficacy of the nucleoside analog 4'-Fluorouridine (4'-FlU, EIDD-2749) against SARS-CoV-2 and respiratory syncytial virus (RSV), we explored activity of the compound against seasonal and highly pathogenic influenza (HPAI) viruses in cell culture, human airway epithelium (HAE) models, and/or two animal models, ferrets and mice, that assess IAV transmission and lethal viral pneumonia, respectively. 4'-FlU inhibited a panel of relevant influenza A and B viruses with nanomolar to sub-micromolar potency in HAE cells. In vitro polymerase assays revealed immediate chain termination of IAV polymerase after 4'-FlU incorporation, in contrast to delayed chain termination of SARS-CoV-2 and RSV polymerase. Once-daily oral treatment of ferrets with 2 mg/kg 4'-FlU initiated 12 hours after infection rapidly stopped virus shedding and prevented transmission to untreated sentinels. Treatment of mice infected with a lethal inoculum of pandemic A/CA/07/2009 (H1N1)pdm09 (pdmCa09) with 4'-FlU alleviated pneumonia. Three doses mediated complete survival when treatment was initiated up to 60 hours after infection, indicating a broad time window for effective intervention. Therapeutic oral 4'-FlU ensured survival of animals infected with HPAI A/VN/12/2003 (H5N1) and of immunocompromised mice infected with pdmCa09. Recoverees were protected against homologous reinfection. This study defines the mechanistic foundation for high sensitivity of influenza viruses to 4'-FlU and supports 4'-FlU as developmental candidate for the treatment of seasonal and pandemic influenza.
Subject(s)COVID-19 , Influenza A Virus, H1N1 Subtype , Influenza A Virus, H5N1 Subtype , Influenza A virus , Influenza, Human , Orthomyxoviridae Infections , Respiratory Syncytial Virus, Human , Humans , Animals , Mice , Influenza, Human/drug therapy , Ferrets , SARS-CoV-2 , Orthomyxoviridae Infections/pathology
Encephalitis is most often caused by a variety of infectious agents identified through diagnostic tests utilizing cerebrospinal fluid. We investigated the clinical characteristics and potential aetiological agents of unexplained encephalitis through metagenomic sequencing of residual clinical samples from multiple tissue types and independent clinical review. Forty-three specimens were collected from 18 encephalitis cases with no cause identified by the Australian Childhood Encephalitis study. Samples were subjected to total RNA sequencing ('metatranscriptomics') to determine the presence and abundance of potential pathogens, and to describe the possible aetiologies of unexplained encephalitis. Using this protocol, we identified five RNA and two DNA viruses associated with human infection from both non-sterile and sterile sites, which were confirmed by PCR. These comprised two human rhinoviruses, two human seasonal coronaviruses, two polyomaviruses and one picobirnavirus. Human rhinovirus and seasonal coronaviruses may be responsible for five of the encephalitis cases. Immune-mediated encephalitis was considered likely in six cases and metatranscriptomics did not identify a possible pathogen in these cases. The aetiology remained unknown in nine cases. Our study emphasizes the importance of respiratory viruses in the aetiology of unexplained child encephalitis and suggests that non-central-nervous-system sampling in encephalitis clinical guidelines and protocols could improve the diagnostic yield.
Subject(s)Encephalitis , Viruses , Australia , Child , Encephalitis/diagnosis , Encephalitis/etiology , Humans , Metagenomics , Polymerase Chain Reaction
ABSTRACT: For 27 years, national prospective data on selected rare childhood diseases have been collected monthly by the Australian Paediatric Surveillance Unit (APSU) from paediatricians and other clinical specialists who report cases in children aged up to 16 years. We report here the annual results of APSU surveillance in 2020 for ten rare communicable diseases and complications of communicable diseases, namely: acute flaccid paralysis (AFP); congenital cytomegalovirus (CMV) infection; neonatal herpes simplex virus (HSV) infection; perinatal exposure to human immunodeficiency virus (HIV); paediatric HIV infection; severe complications of seasonal influenza; juvenile onset recurrent respiratory papillomatosis (JoRRP); congenital rubella syndrome; congenital varicella syndrome; and neonatal varicella infection. We describe the results for each disease in the context of the total period of study, including demographics, clinical characteristics, treatment and short-term outcomes. Despite challenges presented by the coronavirus disease 2019 (COVID-19) pandemic in 2020, more than 1,400 paediatricians reported regularly to the APSU and an overall monthly reporting rate of > 90% was achieved. The minimum AFP target of 1 case per 100,000 children aged less than 15 years was achieved and there were few cases of vaccine-preventable diseases (JoRRP, rubella, varicella). However, high cases of congenital CMV, neonatal HSV and perinatal exposure to HIV persist. There were no severe complications of seasonal influenza reported for the first time in 13 years. This is consistent with other surveillance data reporting a decline of influenza and other communicable diseases in 2020, and likely reflects the wider effects of public health measures to reduce transmission of SARS-CoV-2 in the Australian community.
Subject(s)COVID-19 , HIV Infections , Australia/epidemiology , Child , Female , Humans , Infant, Newborn , Pregnancy , Prospective Studies , SARS-CoV-2
AIM: This study aimed to determine the feasibility and parental acceptability of screening for congenital cytomegalovirus (cCMV) through saliva polymerase chain reaction in infants who did not pass their newborn hearing screening. Additionally, the utility (i.e. time to diagnosis and treatment) of this enhanced clinical pathway was evaluated. METHODS: The study was conducted through the Victorian Infant Hearing Screening Programme (VIHSP) across four maternity hospitals in Melbourne, Australia, during June 2019-March 2020. Parents were approached by VIHSP staff about obtaining a test for cytomegalovirus (CMV) at the time of their baby's second positive ('refer') result on the VIHSP screen. Participating parents collected a saliva swab for CMV polymerase chain reaction from their infants. Feasibility was determined by the proportion of 'referred' infants whose parents completed the salivary CMV screening test ≤21 days of life. Acceptability was measured through parent survey. RESULTS: Of 126 eligible families, 96 (76.0%) had salivary screening swabs taken ≤21 days of life. Most families (>92.0%) indicated that screening was acceptable, straightforward and thought testing their baby for cCMV was a good idea. One infant screened positive on day 30, was diagnosed with cCMV via confirmatory testing by day 31 and commenced valganciclovir on day 32. CONCLUSIONS: Obtaining a saliva sample to screen for cCMV in infants who do not pass their newborn hearing screen is feasible and appears acceptable to parents. This targeted cCMV screening method could be an option where mothers are rapidly discharged from hospital, especially in the context of the COVID-19 pandemic.
Subject(s)COVID-19 , Cytomegalovirus , Feasibility Studies , Female , Hearing , Humans , Infant , Infant, Newborn , Neonatal Screening , Pandemics , Pregnancy , SARS-CoV-2
OBJECTIVES: To describe the features and frequency of respiratory syncytial virus (RSV)-associated severe acute neurologic disease in children. STUDY DESIGN: We performed a systematic review of the literature to identify reports of severe acute neurologic complications associated with acute RSV infection in children aged <15 years (PROSPERO Registration CRD42019125722). Main outcomes included neurologic, clinical, and demographic features of cases and the frequency of disease. We aggregated available case data from the published literature and from the Australian Acute Childhood Encephalitis (ACE) study. RESULTS: We identified 87 unique studies from 26 countries describing a spectrum of RSV-associated severe acute neurologic syndromes including proven encephalitis, acute encephalopathy, complex seizures, hyponatremic seizures, and immune-mediated disorders. The frequency of RSV infection in acute childhood encephalitis/encephalopathy was 1.2%-6.5%. We aggregated data from 155 individual cases with RSV-associated severe acute neurologic complications; median age was 11.0 months (IQR 2.0-21.5), most were previously healthy (71/104, 68%). Seizure was the most frequently reported neurologic feature (127/150, 85%). RSV was detected in the central nervous system of 12 cases. Most children recovered (81/122, 66%); however, some reports described partial recovery (33/122, 27%) and death (8/122, 7%). CONCLUSIONS: RSV-associated neurologic complications have been widely reported, but there is substantial heterogeneity in the design and quality of existing studies. The findings from our study have implications for the investigation, management, and prevention of RSV-associated neurologic complications. Further, this systematic review can inform the design of future studies aiming to quantify the burden of childhood RSV-associated neurologic disease.
Subject(s)Nervous System Diseases/epidemiology , Respiratory Syncytial Virus Infections/epidemiology , Adolescent , Child , Child, Preschool , Diagnostic Tests, Routine/statistics & numerical data , Female , Humans , Incidence , Infant , Male , Respiratory Syncytial Virus, Human/isolation & purification
Transmission-blocking vaccines are urgently needed to reduce transmission of SARS-CoV 2, the cause of the COVID-19 pandemic. The upper respiratory tract is an initial site of SARS-CoV-2 infection and, for many individuals, remains the primary site of virus replication. An ideal COVID-19 vaccine should reduce upper respiratory tract virus replication and block transmission as well as protect against severe disease. Here, we optimized a vaccine candidate, parainfluenza virus 5 (PIV5) expressing the SARS-CoV-2 S protein (CVXGA1), and then demonstrated that a single-dose intranasal immunization with CVXGA1 protects against lethal infection of K18-hACE2 mice, a severe disease model. CVXGA1 immunization also prevented virus infection of ferrets and blocked contact transmission. This mucosal vaccine strategy inhibited SARS-CoV-2 replication in the upper respiratory tract, thus preventing disease progression to the lower respiratory tract. A PIV5-based mucosal vaccine provides a strategy to induce protective innate and cellular immune responses and reduce SARS-CoV-2 infection and transmission in populations.