Vaccines against respiratory syncytial virus.

Respiratory syncytial virus (RSV is) a common respiratory virus responsible for considerable morbidity and mortality among infants, elderly with comorbidity, and immunocompromised adults. Two vaccines, Abrysvo and Arexvy, have been approved for prevention of severe RSV infection in adults ≥ 60 years of age. In addition, Abrysvo is approved for use during pregnancy to protect infants from RSV-associated lower respiratory tract infection. Currently, there is no national recommendation for the use of the vaccines, but vaccination of elderly at highest risk of severe RSV infection should be considered in a shared clinical decision making.

Underreporting and Misclassification of Respiratory Syncytial Virus-Coded Hospitalization Among Adults in Denmark Between 2015-2016 and 2017-2018.

BACKGROUND: Low awareness and lack of routine testing for respiratory syncytial virus (RSV) infections among adults has led to underreporting in hospital records. This study aimed to assess the underreporting and misclassification of RSV infections among adults hospitalized with an respiratory tract infection (RTI)-coded hospitalization. METHODS: This study is an observational cohort study of RSV-associated hospitalizations among Danish adults (≥18 years old) conducted, between 2015 to 2018. Data were extracted from the Danish National Patient Registry (DNPR) and the Danish Microbiology Database. We identified RSV-positive hospitalizations by linking RTI-coded hospitalizations with a positive RSV test. RESULTS: Using hospital admission registries, we identified 440 RSV-coded hospitalizations, of whom 420 (95%) had a positive RSV test registered. By linking patients with RTI-coded hospital admissions to RSV test result, we found 570 additional episodes of RSV-positive hospitalizations without an RSV-coded diagnosis. CONCLUSIONS: Our study of national register data showed that RSV is underreported among Danish adults. The study showed that the reliability of hospitalization data to estimate the burden of RSV among adults is questionable and are sensitive to changes in practice over time, even with complete nationwide healthcare data. Healthcare data can be useful to observe seasonality but to estimate the disease burden, prospective surveillance is recommended.

Genome-Wide Association study of susceptibility to respiratory syncytial virus hospitalization in young children < 5 years of age.

BACKGROUND: Worldwide, respiratory syncytial virus (RSV) infections are among the most common causes of infant hospitalization. Host genetic factors influencing the risk and severity of RSV infection are not well known. METHODS: We conducted a genome-wide association study (GWAS) to investigate single nucleotide polymorphisms (SNPs) associated with severe RSV infections using a nested case-control design based on two Danish cohorts. We compared SNPs from 1786 children hospitalized with RSV to 45,060 controls without a RSV-coded hospitalization. We performed gene-based testing, tissue-enrichment, gene-set enrichment, and a meta-analysis of the two cohorts. Finally, an analysis of potential associations between the severity of RSV infection and genetic markers was performed. RESULTS: We did not detect any significant genome-wide associations between SNPs and RSV infection, or the severity of RSV. We did find potential loci associated with RSV infections on chromosome 5 in one cohort, however, we failed to replicate any signals in both cohorts. CONCLUSION: Despite being the largest GWAS of severe RSV infection, we did not detect any genome-wide significant loci. This may be an indication of a lack of power, or an absence of signal. Future studies might include mild illness and need to be larger to detect any significant associations.

Exercise Training During Working Hours at a Hospital Department: A Pilot Study.

OBJECTIVES: This pilot study tested the use of an exercise offer to hospital employees during working hours and changes in work and health parameters. METHODS: Employees (n = 214) from a medical department on a Danish hospital were invited to 30 minutes' exercise training twice weekly for 12 weeks. Outcomes included health- and work-related parameters. RESULTS: Eighty employees (mean age, 44.4 [SD, 10.7] years; 81.3% women) completed the study. Intervention adherence was 36.3% (SD, 25.1%). Aerobic capacity increased from 34.6 (95% confidence interval [CI], 32.3 to 36.9) to 36.7 (95% CI, 34.1 to 39.4) mL O 2 /min per kilogram, P = 0.004. Blood pressure decreased from 120 (95% CI, 117 to 123)/79 (95% CI, 76 to 81) to 116 (95% CI, 112 to 120)/76 (95% CI, 74 to 79) mm Hg, P = 0.003. Waist circumference and musculoskeletal pain decreased. Well-being, social capital, and quality of life increased. CONCLUSIONS: Despite low training adherence, completers improved outcomes related to metabolic and self-rated health.

Effect of Influenza Vaccination on Risk of Coronavirus Disease 2019: A Prospective Cohort Study of 46†000 Healthcare Workers.

BACKGROUND: The purpose of this study was to assess whether influenza vaccination has an impact on the risk of coronavirus disease 2019 (COVID-19). METHODS: A cohort of 46 112 healthcare workers were tested for antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and filled in a survey on COVID-19 symptoms, hospitalization, and influenza vaccination. RESULTS: The risk ratio of hospitalization due to SARS-CoV-2 for influenza vaccinated compared with unvaccinated participants was 1.00 for the seasonal vaccination in 2019/2020 (confidence interval, .56-1.78, P = 1.00). Likewise, no clinical effect of influenza vaccination on development of antibodies against SARS-CoV-2 was found. CONCLUSIONS: The present findings indicate that influenza vaccination does not affect the risk of SARS-CoV-2 infection or COVID-19.

Risk Factors for Being Seronegative following SARS-CoV-2 Infection in a Large Cohort of Health Care Workers in Denmark.

Most individuals seroconvert after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but being seronegative is observed in 1 to 9%. We aimed to investigate the risk factors associated with being seronegative following PCR-confirmed SARS-CoV-2 infection. In a prospective cohort study, we screened health care workers (HCW) in the Capital Region of Denmark for SARS-CoV-2 antibodies. We performed three rounds of screening from April to October 2020 using an enzyme-linked immunosorbent assay (ELISA) method targeting SARS-CoV-2 total antibodies. Data on all participants' PCR for SARS-CoV-2 RNA were captured from national registries. The Kaplan-Meier method and Cox proportional hazards models were applied to investigate the probability of being seronegative and the related risk factors, respectively. Of 36,583 HCW, 866 (2.4%) had a positive PCR before or during the study period. The median (interquartile range [IQR]) age of 866 HCW was 42 (31 to 53) years, and 666 (77%) were female. After a median of 132 (range, 35 to 180) days, 21 (2.4%) of 866 were seronegative. In a multivariable model, independent risk factors for being seronegative were self-reported asymptomatic or mild infection hazard ratio (HR) of 6.6 (95% confidence interval [CI], 2.6 to 17; P < 0.001) and body mass index (BMI) of ≥30, HR 3.1 (95% CI, 1.1 to 8.8; P = 0.039). Only a few (2.4%) HCW were not seropositive. Asymptomatic or mild infection as well as a BMI above 30 were associated with being seronegative. Since the presence of antibodies against SARS-CoV-2 reduces the risk of reinfection, efforts to protect HCW with risk factors for being seronegative may be needed in future COVID-19 surges. IMPORTANCE Most individuals seroconvert after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but negative serology is observed in 1 to 9%. We found that asymptomatic or mild infection as well as a BMI above 30 were associated with being seronegative. Since the presence of antibodies against SARS-CoV-2 reduces the risk of reinfection, efforts to protect HCW with risk factors for being seronegative may be needed in future COVID-19 surges.

Response to influenza vaccination in immunocompromised children with rheumatic disease: a prospective cohort study.

BACKGROUND: Prevention of illness due to infection by influenza viruses is important for children with rheumatic diseases. Biological disease modifying antirheumatic drugs have become increasingly important in the treatment of juvenile idiopathic arthritis, and combinations of immunosuppressive drugs are used for the treatment of systemic disorders, which increase the risk of secondary immunodeficiency. Therefore, we investigated whether children with rheumatic disease can mount a protective antibody response after influenza immunization. METHODS: The prospective multicentre cohort study was conducted in Denmark during the influenza season 2015-2016. Children with rheumatic disease aged six months to 19 years were eligible. Controls were immunologically healthy children. A blood sample was collected before and after vaccination and analysed by haemagglutination inhibition (HI) assay for the 2015-2016 influenza vaccine-strains. In case of flu-like symptoms the child was tested for influenza. For statistical analyses the patients were grouped according to medical treatment or disease. RESULTS: A total of 226 patients and 15 controls were enrolled. No differences were found for the increase of antibodies from pre-vaccine to post-vaccine between the groups in our primary analyses: A/Cal H1N1pdm09 (p = 0.28), A/Swi H3N2 (p = 0.15) and B/Phu Yamagata (p = 0.08). Only when combining patients across groups a lower increase in antibodies was found compared to controls. Among all patients the pre-vaccine rates for seroprotection using the HI-titer cut-off ≥ 40 were 93.1-97.0 % for all three strains. For seroprotection using the HI-titer cut-off ≥ 110 the pre-vaccine rates for all patients were 14.9-43.6 % for all three strains and an increase in the proportions of patients being seroprotected after vaccination was found for A/Cal H1N1pdm09 and A/Swi H3N2. None of the children with flu-like symptoms tested positive for the vaccine strains. CONCLUSIONS: Children with rheumatic diseases increase in antibody titres after influenza immunization, however, it remains uncertain whether a protective level is achieved.

[Epidemiology, clinical manifestations and treatment of SARS-CoV-2 infection in children].

SARS-CoV-2 infection causes COVID-19. Most infected children have asymptomatic or mild clinical manifestations. A few develop serious illness, and the case fatality rate is lower than in adults. The most frequent symptoms are fever and cough. Studies indicate that children might be less susceptible to infection than adults as summarised in this review. Despite mild manifestation, some children experience a hyper-inflammatory response to SARS-CoV-2 infection called multisystem inflammatory syndrome, similarly to Kawasaki disease. The syndrome is still very rare, and the pathogenesis remains unknown.

First wave of COVID-19 hospital admissions in Denmark: a Nationwide population-based cohort study.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its associated disease coronavirus disease 2019 (COVID-19), is a worldwide emergency. Demographic, comorbidity and laboratory determinants of death and of ICU admission were explored in all Danish hospitalised patients. METHODS: National health registries were used to identify all hospitalized patients with a COVID-19 diagnosis. We obtained demographics, Charlson Comorbidity Index (CCI), and laboratory results on admission and explored prognostic factors for death using multivariate Cox proportional hazard regression and competing risk survival analysis. RESULTS: Among 2431 hospitalised patients with COVID-19 between February 27 and July 8 (median age 69 years [IQR 53-80], 54.1% males), 359 (14.8%) needed admission to an intensive care unit (ICU) and 455 (18.7%) died within 30 days of follow-up. The seven-day cumulative incidence of ICU admission was lower for females (7.9%) than for males (16.7%), (p < 0.001). Age, high CCI, elevated C-reactive protein (CRP), ferritin, D-dimer, lactate dehydrogenase (LDH), urea, creatinine, lymphopenia, neutrophilia and thrombocytopenia within ±24-h of admission were independently associated with death within the first week in the multivariate analysis. Conditional upon surviving the first week, male sex, age, high CCI, elevated CRP, LDH, creatinine, urea and neutrophil count were independently associated with death within 30 days. Males presented with more pronounced laboratory abnormalities on admission. CONCLUSIONS: Advanced age, male sex, comorbidity, higher levels of systemic inflammation and cell-turnover were independent factors for mortality. Age was the strongest predictor for death, moderate to high level of comorbidity were associated with a nearly two-fold increase in mortality. Mortality was significantly higher in males after surviving the first week.

Influenza and COVID-19: What does co-existence mean?

The COVID-19 pandemic caused by the novel coronavirus SARS-CoV-2 continues to have a major impact on healthcare and social systems throughout the world. As the clinical and epidemiological features of COVID-19 have many parallels with influenza, it is important to ensure optimal management of both respiratory diseases as we anticipate their continued co-circulation. In particular, there is a need to ensure that effective surveillance and diagnostic capacities are in place to monitor these and other respiratory viruses, as this will underpin decisions on the appropriate clinical management of the respective diseases. As such, we propose a series of key recommendations for stakeholders, public health authorities, primary care physicians and surveillance bodies that will help mitigate the combined risks of concurrent influenza epidemics and the COVID-19 pandemic. We advocate the judicious use of influenza vaccines and antivirals, particularly among groups at high risk of complications, with healthcare workers also considered a priority for vaccination. It is likely that the increased use of emerging technologies such as telemedicine and contact tracing will permanently change our approach to managing infectious disease. The use of these technologies, alongside existing pharmaceutical strategies, will ensure that we achieve a holistic approach to the global public health measures needed to deal with the combined threat of influenza and COVID-19. Ensuring that this approach is optimal will be key as we move from a reactive pandemic response towards preparing for the long-term management of the remarkable clinical burden associated with these respiratory pathogens.

Respiratory Syncytial Virus-Associated Hospital Admissions in Children Younger Than 5 Years in 7 European Countries Using Routinely Collected Datasets.

BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of respiratory tract infection (RTI) in young children. Registries provide opportunities to explore RSV epidemiology and burden. METHODS: We explored routinely collected hospital data on RSV in children aged < 5 years in 7 European countries. We compare RSV-associated admission rates, age, seasonality, and time trends between countries. RESULTS: We found similar age distributions of RSV-associated hospital admissions in each country, with the highest burden in children < 1 years old and peak at age 1 month. Average annual rates of RTI admission were 41.3-112.0 per 1000 children aged < 1 year and 8.6-22.3 per 1000 children aged < 1 year. In children aged < 5 years, 57%-72% of RTI admissions with specified causal pathogen were coded as RSV, with 62%-87% of pathogen-coded admissions in children < 1 year coded as RSV. CONCLUSIONS: Our results demonstrate the benefits and limitations of using linked routinely collected data to explore epidemiology and burden of RSV. Our future work will use these data to generate estimates of RSV burden using time-series modelling methodology, to inform policymaking and regulatory decisions regarding RSV immunization strategy and monitor the impact of future vaccines.

Characteristics and early outcomes of patients hospitalised for COVID-19 in North Zealand, Denmark.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is an ongoing pandemic associated with significant morbidity and mortality worldwide. Limited data are available describing the clinical presentation and outcomes of hospitalised COVID-19 patients in Europe. METHODS: This was a single-centre retrospective chart review of all patients with COVID-19 admitted to the North Zealand Hospital in Denmark between 1 March and 4 May 2020. Main outcomes include major therapeutic interventions during hospitalisation, such as invasive mechanical ventilation, as well as death. RESULTS: A total of 115 patients were included, including four infants. The median age of adults was 68 years and 40% were female. At admission, 55 (50%) patients had a fever, 29 (26%) had a respiratory rate exceeding 24 breaths/minute, and 78 (70%) received supplemental oxygen. The prevalence of co-infection was 13%. Twenty patients (18%) (median age: 64 years; 15% female) were treated in the intensive care unit. Twelve (10.4%) received invasive mechanical ventilation and three (2.6%) renal replacement therapy. Nine patients (8%) developed pulmonary embolism. Sixteen patients (14%) died. Among patients requiring mechanical ventilation (n = 12), seven (6.1%) were discharged alive, four (3.4%) died and one (0.9%) was still hospitalised. CONCLUSION: In this cohort of hospitalised COVID-19 patients, mortality was lower than in other Danish and European case series. FUNDING: none. TRIAL REGISTRATION: not relevant.

Aseptic meningitis outbreak associated with echovirus 4 in Northern Europe in 2013-2014.

Picornaviruses (family Picornaviridae) are small, nonenveloped, positive-sense, single-stranded RNA viruses. The members of this family are currently classified into 47 genera and 110 species. Of picornaviruses, entero- and parechoviruses are associated with aseptic meningitis. They are transmitted via fecal-oral and respiratory routes, and occasionally, these viruses may cause a brief viremia and gain access to central nervous system (CNS). During the diagnostic screening of entero- and parechovirus types in Finland in year 2013-14, we detected a cluster of echovirus 4 (E4) infections in young adults and adolescents. As E4 is infrequently detected in Finland, we contacted several Northern and Central European laboratories that conduct routine surveillance for enteroviruses and, for those who have had E4 cases, we send a query for E4 sequences and data. Here we report CNS infections caused by E4 in Finland, Sweden, Norway, Denmark, Iceland and Germany in 2013 and 2014, and show that the E4 detected in these countries form a single lineage. In contrast, E4 strains circulating in these countries preceding the year 2013, and those circulating elsewhere in Europe during 2013-2014, formed several independent clusters.

Correction: Seasonality of ventricular fibrillation at first myocardial infarction and association with viral exposure.

[This corrects the article DOI: 10.1371/journal.pone.0226936.].

Improving preparedness to respond to cross-border hepatitis A outbreaks in the European Union/European Economic Area: towards comparable sequencing of hepatitis A virus.

IntroductionSequence-based typing of hepatitis A virus (HAV) is important for outbreak detection, investigation and surveillance. In 2013, sequencing was central to resolving a large European Union (EU)-wide outbreak related to frozen berries. However, as the sequenced HAV genome regions were only partly comparable between countries, results were not always conclusive.AimThe objective was to gather information on HAV surveillance and sequencing in EU/European Economic Area (EEA) countries to find ways to harmonise their procedures, for improvement of cross-border outbreak responses.MethodsIn 2014, the European Centre for Disease Prevention and Control (ECDC) conducted a survey on HAV surveillance practices in EU/EEA countries. The survey enquired whether a referral system for confirming primary diagnostics of hepatitis A existed as well as a central collection/storage of hepatitis A cases' samples for typing. Questions on HAV sequencing procedures were also asked. Based on the results, an expert consultation proposed harmonised procedures for cross-border outbreak response, in particular regarding sequencing. In 2016, a follow-up survey assessed uptake of suggested methods.ResultsOf 31 EU/EEA countries, 23 (2014) and 27 (2016) participated. Numbers of countries with central collection and storage of HAV positive samples and of those performing sequencing increased from 12 to 15 and 12 to 14 respectively in 2016, with all countries typing an overlapping fragment of 218 nt. However, variation existed in the sequenced genomic regions and their lengths.ConclusionsWhile HAV sequences in EU/EEA countries are comparable for surveillance, collaboration in sharing and comparing these can be further strengthened.

Selection and Interpretation of Scientific Evidence in Preparation for Policy Decisions: A Case Study Regarding Introduction of Rotavirus Vaccine Into National Immunization Programs in Sweden, Norway, Finland, and Denmark.

The World Health Organization recommends inclusion of rotavirus vaccines in national immunization programs (NIPs) worldwide. Nordic countries are usually considered comparable in terms of demographics and health-care services and have comparable rotavirus disease burden. Nevertheless, the countries have reached different decisions regarding rotavirus vaccine: Norway and Finland have already introduced rotavirus vaccines into their NIPs and Sweden is currently changing its recommendation and vaccines will now be introduced on a national scale while Denmark has decided against it. This study focuses on the selection and interpretation of medical and epidemiological evidence used during the decision-making processes in Sweden, Norway, Finland, and Denmark. The so-called "severity criteria" is identified as one of the main reasons for the different policy decisions reached across the Nordic countries.

Zika Virus IgG in Infants with Microcephaly, Guinea-Bissau, 2016.

We analyzed blood samples from infants born with microcephaly and their mothers in Guinea-Bissau in 2016 for pathogens associated with birth defects. No Zika virus RNA was detected, but Zika virus IgG was highly prevalent. We recommend implementing pathogen screening of infants with congenital defects in Guinea-Bissau.

Antiviral resistance due to deletion in the neuraminidase gene and defective interfering-like viral polymerase basic 2 RNA of influenza A virus subtype H3N2.

BACKGROUND AND OBJECTIVE: Antiviral treatment of influenza virus infections can lead to drug resistance of virus. This study investigates a selection of mutations in the full genome of H3N2 influenza A virus isolated from a patient in treatment with oseltamivir. STUDY DESIGN: Respiratory samples from a patient were collected before, during, and after antiviral treatment. Whole genome sequencing of the influenza virus by next generation sequencing, and low-frequency-variant analysis was performed. Neuraminidase-inhibition tests were performed with oseltamivir and zanamivir, and viruses were propagated in sial-transferase gene transfected Madin-Darby Canine Kidney cells. RESULTS: A deletion at amino acid position 245-248 in the neuraminidase gene occurred after initiation of treatment with oseltamivir. The deleted virus had highly reduced inhibition against oseltamivir but was sensitive to zanamivir. Nine days after discontinuation of oseltamivir treatment the deleted H3N2 virus was still present in the patient. After three passages of the deleted virus in cell culture, the deletion was retained. Several variant mutations appeared in the other genes of the H3N2 virus, where most striking were two major out-of-frame deletions in the polymerase basic 2 (PB2) gene, indicating defective interfering-like viral RNA. CONCLUSIONS: The viruses harboring the 245-248 deletion in the neuraminidase gene were still present after discontinuation of oseltamivir treatment and passages in cell cultures, indicating a potential risk for transmission of the deleted virus. Full genome deep sequencing was useful to reveal variant mutations that might be selected due to antiviral treatment, and defective interfering-like viral PB2 RNA in the respiratory samples was detected.

An enhanced Enterovirus surveillance system allows identification and characterization of rare and emerging respiratory enteroviruses in Denmark, 2015-16.

BACKGROUND: The potential for outbreaks due to Enteroviruses (EV) with respiratory tropism, such as EV-D68, and the detection of new and rare EV species C is a concern. These EVs are typically not detected in stool specimens and may therefore be missed by standard EV surveillance systems. Following the North American outbreak of EV-D68 in 2014, Denmark piloted an enhanced EV surveillance system that included the screening of respiratory samples. OBJECTIVES: We aim to report clinical manifestations and phylogenetic descriptions from the rare and emerging EVs identified thereby demonstrating the usefulness of this system. STUDY DESIGN: Positive EV samples received through the enhanced non-polio EV pilot surveillance system were characterized by sequencing fragments of VP1, VP2 and VP4 capsid proteins and clinical observations were compiled. RESULTS: Between January 2015 and October 2016, six cases of rare genotypes EV-C104, C105 and C109 and nine cases of EV-D68 were identified. Patients presented with mild to moderately severe respiratory illness; no paralysis occurred. Distinct EV-C104, EV-C109 and EV-D68 sequences argue against a common source of introduction of these genotypes in the Danish population. CONCLUSIONS: The enhanced EV surveillance system enabled detection and characterization of rare EVs in Denmark. In order to improve our knowledge of and our preparedness against emerging EVs, public health laboratories should consider expanding their EV surveillance system to include respiratory specimens.

A universal primer-independent next-generation sequencing approach for investigations of norovirus outbreaks and novel variants.

Norovirus (NoV) is the most common cause of non-bacterial gastroenteritis and is a major agent associated with outbreaks of gastroenteritis. Conventional molecular genotyping analysis of NoV, used for the identification of transmission routes, relies on standard typing methods (STM) by Sanger-sequencing of only a limited part of the NoV genome, which could lead to wrong conclusions. Here, we combined a NoV capture method with next generation sequencing (NGS), which increased the proportion of norovirus reads by ~40 fold compared to NGS without prior capture. Of 15 NoV samples from 6 single-genotype outbreaks, near full-genome coverage (>90%) was obtained from 9 samples. Fourteen polymerase (RdRp) and 15 capsid (cap) genotypes were identified compared to 12 and 13 for the STM, respectively. Analysis of 9 samples from two mixed-genotype outbreaks identified 6 RdRp and 6 cap genotypes (two at >90% NoV genome coverage) compared to 4 and 2 for the STM, respectively. Furthermore, complete or partial sequences from the P2 hypervariable region were obtained from 7 of 8 outbreaks and a new NoV recombinant was identified. This approach could therefore strengthen outbreak investigations and could be applied to other important viruses in stool samples such as hepatitis A and enterovirus.