RESUMEN
Large-scale serosurveillance of severe acute respiratory syndrome coronavirus type 2 (SARS- CoV-2) will only be possible if serological tests are sufficiently reliable, rapid and inexpensive. Current assays are either labour-intensive and require specialised facilities (e.g. virus neutralization assays), or expensive with suboptimal specificity (e.g. commercial ELISAs). Bead-based assays offer a cost-effective alternative and allow for multiplexing to test for antibodies of other pathogens. Here, we compare the performance of four antigens for the detection of SARS-CoV-2 specific IgG antibodies in a panel of sera that includes both severe (n=40) and mild (n=52) cases, using a neutralization and a Luminex bead-based assay. While we show that neutralising antibody levels are significantly lower in mild than in severe cases, we demonstrate that a combination of recombinant nucleocapsid protein (NP), receptor- binding domain (RBD) and the whole spike protein (S1S2) results in a highly sensitive (96%) and specific (99%) bead-based assay that can detect IgG antibodies in both groups. Although S1-specific IgG levels correlate most strongly with neutralizing antibody levels, they fall below the detection threshold in 10% of the cases in our Luminex assay. In conclusion, our data supports the use of RBD, NP and S1S2 for the development of SARS-CoV-2 serological bead- based assays. Finally, we argue that low antibody levels in mild/asymptomatic cases might complicate the epidemiological assessment of large-scale surveillance studies.
RESUMEN
Background@#The World Health Organization recommends that children aged ≥6 months be vaccinated against influenza. Influenza vaccination policies depend on the evidence of the burden of influenza, yet few national data on influenza-associated severe outcomes among children exist in China.@*Methods@#We conducted a systematic review of articles published from 1996 to 2012 on laboratory-confirmed, influenza-associated paediatric respiratory hospitalizations in China. We extracted data and stratified the percentage of samples testing positive for influenza by age group (<2, <5 and <18 years old); case definition; test methods; and geographic location. The pooled percentage of samples testing positive for influenza was estimated with a random effects regression model.@*Results@#Influenza was associated with 8.8% of respiratory hospitalizations among children aged <18 years, ranging from 7.0% (95% confidence interval: 4.2–9.8%) in children aged <2 years to 8.9% (95% confidence interval: 6.8–11%) in children aged <5 years. The percentage of samples testing positive for influenza was consistently higher among studies with data from children aged <5 years and <18 years than those restricted only to children aged <2 years; the percentages were higher in Northern China than Southern China.@*Discussion@#Influenza is an important cause of paediatric respiratory hospitalizations in China. Influenza vaccination of school-aged children could prevent substantial influenza-associated illness, including hospitalizations, in China.
RESUMEN
Recent experience with pandemic influenza A(H1N1)pdm09 highlighted the importance of global surveillance for severe respiratory disease to support pandemic preparedness and seasonal influenza control. Improved surveillance in the southern hemisphere is needed to provide critical data on influenza epidemiology, disease burden, circulating strains and effectiveness of influenza prevention and control measures. Hospital-based surveillance for severe acute respiratory infection (SARI) cases was established in New Zealand on 30 April 2012. The aims were to measure incidence, prevalence, risk factors, clinical spectrum and outcomes for SARI and associated influenza and other respiratory pathogen cases as well as to understand influenza contribution to patients not meeting SARI case definition.All inpatients with suspected respiratory infections who were admitted overnight to the study hospitals were screened daily. If a patient met the World Health Organization’s SARI case definition, a respiratory specimen was tested for influenza and other respiratory pathogens. A case report form captured demographics, history of presenting illness, co-morbidities, disease course and outcome and risk factors. These data were supplemented from electronic clinical records and other linked data sources.Hospital-based SARI surveillance has been implemented and is fully functioning in New Zealand. Active, prospective, continuous, hospital-based SARI surveillance is useful in supporting pandemic preparedness for emerging influenza A(H7N9) virus infections and seasonal influenza prevention and control.