Low pre-vaccination SARS-CoV-2 seroprevalence in Finnish health care workers: a prospective cohort study

Background: Health care workers are at risk of acquiring SARS-CoV-2 infection. Our aim was to study the prevalence of SARS-CoV-2 nucleoprotein and spike protein specific antibodies in health care workers with occupational exposure to COVID-19 in Turku, Finland, from May to December 2020.Methods: Health care workers of Turku University Hospital units caring for COVID-19 patients or handling clinical SARS-CoV-2 samples were invited to participate in the study. The presence of SARS-CoV-2 nucleoprotein and spike protein specific IgG antibodies were analysed with in-house enzyme immunoassay.Results: At study enrolment, only one of the 222 (0.5%) study participants was seropositive for SARS-CoV-2 protein specific antibodies. Two additional study participants (2/222, 0.9%) seroconverted during the follow-up. All these participants were diagnosed with a RT-PCR-positive COVID-19 infection before turning seropositive.Conclusion: In our study population, the prevalence of SARS-CoV-2 seropositivity remained low. The absence of seropositive cases without previous RT-PCR confirmed infections demonstrate good access to diagnostics. In addition to high vaccine coverage, high standards of infection prevention practices and use of standard personal protective equipment seem sufficient in preventing occupational SARS-CoV-2 infection in a setting with low number of circulating virus. However, it remains unclear whether similar protective practices would also be effective against more transmissible SARS-CoV-2 variants.</p

Genetic and morphometric differentiation among sympatric spawning stocks of whitefish (Coregonus lavaretus L.) in Lake Femund, Norway

Lake Femund, Norway, contains several sympatric ecotypes of whitefish, Coregonus lavaretus L. Deepwater whitefish, river whitefish, and shallow water whitefish can be easily distinguished by spawning habitat and gillraker number. Variation in morphological and ecological characters and allozyme loci from 11 different spawning sites was analysed to compare the ecological polymorphism with possible genetic sub-structuring of whitefish in the lake. Of the individual morphological and ecological characters, gillraker number best separated the spawning populations, followed by body length. In a hierarchical cluster analysis based on gillraker number, body length and age of fish, the four deepwater sites grouped together as well as the three samples from, or closely related to, inlet rivers. The shallow water sites, however, were more dispersed. In the allozyme analysis, nine of the 38 enzyme loci were polymorphic at the 0.95 level. The amount of genetic variation was quite similar among localities with Hexp = 0.046 - 0.066. Allele frequencies differed significantly among localities at all polymorphic loci indicating distinct reproductive isolation between spawning sites. A consensus tree based on genetic distances grouped samples according to spawning depth and trophic morphology rather than regional proximity. All deepwater spawners grouped together with rather high support while geographically adjacent samples differing by their morphology or behaviour were dispersed. The patterns of differentiation based on allozyme variation and morphology are not fully concordant, but still the association between genetic differentiation and morphological and life history variables was highly significant. Thus, the morphological differences are not due to phenotypic plasticity within single spawning populations as is commonly seen in many other fish species. The possible evolutionary origins of reproductively isolated whitefish forms are discussed. The relatively close association between differences in gillraker counts and genetic difference indicates that the present management of Femund whitefish stocks based on gillraker counts is sensible

Understanding the Strategies and Practices of Facebook Microcelebrities for Engaging in Sociopolitical Discourses

In this paper, we study popular microcelebrities from the Global South to understand their strategies and practices on Facebook. Unlike traditional celebrities who gain their reputation through different types of physical performance, these microcelebrities attain their status by presenting themselves in a favorable way to their online followers. We conducted interviews with 19 microcelebrities from Bangladesh and analyzed our data using actor-network theory (ANT) and Goffman’s dramaturgical analysis (DA) of human interaction. We discuss the complex socio-technical ecosystem of the microcelebrity and the roles of non-human actors, such as platforms and local internet infrastructure along with human actors’ practices. We explain the microcelebrities’ experience with the process of microcelebritification–the process of being a microcelebrity on social media through impression management, and becoming opinion leaders in local sociopolitical discourses as part of their online identity. Our paper contributes to the emerging literature on microcelebrities by highlighting the process viewed in the context of the Global South.peerReviewe

A Combination of N and S Antigens With IgA and IgG Measurement Strengthens the Accuracy of SARS-CoV-2 Serodiagnostics

Background. Primary diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is based on detection of virus RNA in nasopharyngeal swab samples. In addition, analysis of humoral immunity against SARS-CoV-2 has an important role in viral diagnostics and seroprevalence estimates. Methods. We developed and optimized an enzyme immunoassays (EIA) using SARS-CoV-2 nucleoprotein (N), Si and receptor binding domain (RBD) of the viral spike protein, and N proteins from SARS, Middle East respiratory syndrome (MERS), and 4 low-pathogenic human CoVs. Neutralizing antibody activity was compared with SARS-CoV-2 IgG, IgA, and IgM EIA results. Results. The sensitivity of EIA for detecting immune response in COVID-19 patients (n = 101) was 77% in the acute phase and 100% in the convalescent phase of SARS-CoV-2 infection when N and RBD were used as antigens in IgG and IgA specific EIAs. SARS-CoV-2 infection significantly increased humoral immune responses against the 229E and NL63 N proteins. Si and RBD-based EIA results had a strong correlation with microneutralization test results. Conclusions. The data indicate a combination of SARS-CoV-2 Si or RBD and N proteins and analysis of IgG and IgA immunoglobulin classes in sera provide an excellent basis for specific and sensitive serological diagnostics of COVID-19.Peer reviewe