Evaluation of a SARS-CoV-2 Surrogate Virus Neutralization Test for Detection of Antibody in Human, Canine, Cat, and Hamster Sera.

Surrogate neutralization assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that can be done without biosafety level 3 containment and in multiple species are desirable. We evaluate a recently developed surrogate virus neutralization test (sVNT) in comparison to 90% plaque reduction neutralization tests (PRNT90) in human, canine, cat, and hamster sera. With PRNT90 as the reference, sVNT had sensitivity of 98.9% and specificity of 98.8%. Using a panel of immune sera corresponding to other coronaviruses, we confirm the lack of cross-reactivity to other coronaviruses in SARS-CoV-2 sVNT and PRNT90, except for cross-reactivity to SARS-CoV-1 in sVNT.

Serological assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), March 2020.

BackgroundThe ongoing coronavirus disease (COVID-19) pandemic has major impacts on health systems, the economy and society. Assessing infection attack rates in the population is critical for estimating disease severity and herd immunity which is needed to calibrate public health interventions. We have previously shown that it is possible to achieve this in real time to impact public health decision making.AimOur objective was to develop and evaluate serological assays applicable in large-scale sero-epidemiological studies.MethodsWe developed an ELISA to detect IgG and IgM antibodies to the receptor-binding domain (RBD) of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We evaluated its sensitivity and specificity in combination with confirmatory microneutralisation (MN) and 90% plaque reduction neutralisation tests (PRNT90) in 51 sera from 24 patients with virologically confirmed COVID-19 and in age-stratified sera from 200 healthy controls.ResultsIgG and IgM RBD ELISA, MN and PRNT90 were reliably positive after 29 days from illness onset with no detectable cross-reactivity in age-stratified controls. We found that PRNT90 tests were more sensitive in detecting antibody than MN tests carried out with the conventional 100 tissue culture infectious dose challenge. Heparinised plasma appeared to reduce the infectivity of the virus challenge dose and may confound interpretation of neutralisation test.ConclusionUsing IgG ELISA based on the RBD of the spike protein to screen sera for SARS-CoV-2 antibody, followed by confirmation using PRNT90, is a valid approach for large-scale sero-epidemiology studies.

An indicator of appropriate neuroleptic prescribing in nursing homes.

OBJECTIVE: To derive and apply objective criteria which assess the appropriateness of neuroleptic prescribing, in a random sample of nursing homes. DESIGN: Cross-sectional survey of prescribing in a random sample of nursing homes. SETTING: 22 homes with more than 35 residents in the former South Thames Region. SUBJECTS: 934 nursing home residents aged 65 years or over. METHODS: We compared criteria of appropriate neuroleptic prescribing, including appropriate indication and review, to clinical data documented in the nursing and GP notes of residents prescribed neuroleptics. RESULTS: Of the 229 (24.5%) residents prescribed neuroleptics, clinical notes were available for 225. Clinical data indicated that only 40/225 (17.8%) residents receiving neuroleptics received appropriate therapy. The intra-cluster correlations for appropriate and inappropriate prescribing of neuroleptics were 0.038 and 0.12 respectively. It was not possible to derive reference ranges of observed prescribing that included homes demonstrating appropriate prescribing whilst excluding those with inappropriate prescribing. Thus, clinical data are needed whenever neuroleptic appropriateness is assessed. Criteria were readily applicable in nursing homes. CONCLUSION: Application of criteria of appropriate neuroleptic prescribing in a random sample of nursing homes identified suboptimal prescribing to elderly residents.