ABSTRACT
We studied the development of SARS-CoV-2 pandemic in Finland in 2020 and evaluated the performance of two surrogate immunoassays for detection of neutralizing antibodies (NAbs). The dataset consisted of 12000 retrospectively collected samples from pregnant women in their 1st trimester throughout 2020. All the samples were initially screened for IgG with SARS-CoV-2 spike antibody assay (EIM-S1, Euroimmun, Lybeck, Germany) followed by confirmation with nucleocapsid antibody assay (Architect SARS-CoV-2, Abbott, Illinois, USA). Samples that were reactive (positive or borderline) with both assays were subjected to testing with commercial surrogate immunoassays of NeutraLISA (EIM) and cPass (GenScript Biotech Corporation, Rijswijk, Netherlands) by using pseudoneutralization assay (PNAbA) as a golden standard. No seropositive cases were detected between January and March. Between April and December, IgG (EIM-S1 and Abbott positive) and NAb (PNAbA positive) seroprevalences were between 0.4-1.4%. NeutraLISA showed 90% and cPass 55% concordant results with PNAbA among PNAbA negative samples and 49% and 92% among PNAbA positive samples giving NeutraLISA better specificity but lower sensitivity than cPass. To conclude, seroprevalence in pregnant women reflected that of the general population but the variability of the performance of serological protocols needs to be taken into account in inter-study comparison.
Subject(s)
Severe Acute Respiratory SyndromeABSTRACT
We report an experimental infection of American mink with SARS-CoV-2 Omicron variant and show that mink remain virus RNA positive for days, develop clinical sings and histopathological changes, and transmit the virus to uninfected recipients warranting further studies and preparedness.
ABSTRACT
SARS-CoV-2 has been detected both in air and on surfaces, but questions remain about the patient-specific and environmental factors affecting virus transmission to the environment. Additionally, more detailed information on viral findings in air is needed. This cross-sectional study presents results from 259 air and 252 surface samples from the surroundings of 23 hospitalized and eight home-treated COVID-19 patients between July 2020 and March 2021 and compares the results between the measured environments and patient factors. The proportions of PCR-positive air and surface samples showed statistical similarity in hospital and in the home. In four cases, positive environmental samples were detected even after the patients had developed a neutralizing IgG response. SARS-CoV-2 RNA was detected in the following particle sizes: 0.65–4.7 µm, >7 µm, >10 µm, and <100 µm. Appropriate infection control against airborne and surface transmission routes is needed in both environments, even after antibody production has begun.
Subject(s)
COVID-19ABSTRACT
Finland has had a low incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infections as compared to most European countries. Here we report the origins and turnover of SARS-CoV-2 lineages circulating in Finland in 2020. SARS-CoV-2 introduced to Finland in January 2020 and spread rapidly across southern Finland during spring. We observed rapid turnover among Finnish lineages during this period. Clade 20C became the most prevalent among sequenced cases and was replaced by other strains in fall 2020. Bayesian phylogeographic reconstructions suggested 42 independent introductions into Finland during spring 2020, mainly from Italy, Austria, and Spain, which might have been the source for a third of cases. The investigations of the original introductions of SARS-CoV-2 to Finland during the early stages of the pandemic and of the subsequent lineage dynamics could be utilized to assess the role of transboundary movements and effects of early intervention and public health measures.
Subject(s)
Coronavirus InfectionsABSTRACT
SARS-CoV-2 infection raises neutralizing antibodies (NAbs). While studies have shown differing NAb kinetics, they generally point to the antibody arm of immunity providing most recoverees protection against contemporary strains. However, the effect against newly emerged variants of concern (VoCs) has remained uncertain. Here, applying neutralization tests to paired recoveree sera (N=38) of spring 2020 COVID-19 patients with clinical isolates of wildtype D614G and VoC1 and -2 strains (B.1.1.7 and B 1.351) from Finland, we show that NAbs of these patients are equally effective in inhibiting both contemporary and VoC1 strains whereas inhibition of VoC2 is reduced 8-fold (p<0.001) with 50% of sera failing to show NAbs. Our results align with an increased ability of VoC2 to reinfect previously SARS-CoV-infected populations.