SARS-CoV-2-Specific Neutralizing Antibody Responses in Norwegian Health Care Workers After the First Wave of COVID-19 Pandemic: A Prospective Cohort Study.

During the coronavirus disease 2019 (COVID-19) pandemic, many countries experienced infection in health care workers (HCW) due to overburdened health care systems. Whether infected HCW acquire protective immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unclear. In a Norwegian prospective cohort study, we enrolled 607 HCW before and after the first COVID-19 wave. Exposure history, COVID-19-like symptoms, and serum samples were collected. SARS-CoV-2-specific antibodies were characterized by spike-protein IgG/IgM/IgA enzyme-linked immunosorbent and live-virus neutralization assays. Spike-specific IgG/IgM/IgA antibodies increased after the first wave in HCW with, but not in HCW without, COVID-19 patient exposure. Thirty-two HCW (5.3%) had spike-specific antibodies (11 seroconverted with ≥4-fold increase, 21 were seropositive at baseline). Neutralizing antibodies were found in 11 HCW that seroconverted, of whom 4 (36.4%) were asymptomatic. Ninety-seven HCW were tested by reverse transcriptase polymerase chain reaction (RT-PCR) during follow-up; 8 were positive (7 seroconverted, 1 had undetectable antibodies). We found increases in SARS-CoV-2 neutralizing antibodies in infected HCW, especially after COVID-19 patient exposure. Our data show a low number of SARS-CoV-2-seropositive HCW in a low-prevalence setting; however, the proportion of seropositivity was higher than RT-PCR positivity, highlighting the importance of antibody testing.

Trieu MC ，Bansal A ，Madsen A ，Zhou F ，Sævik M ，Vahokoski J ，Brokstad KA ，Krammer F ，Tøndel C ，Mohn KGI ，Blomberg B ，Langeland N ，Cox RJ ，Bergen COVID-19 Research Group ... -  《-》

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

Johannesen CK ，Rezahosseini O ，Gybel-Brask M ，Kristensen JH ，Hasselbalch RB ，Pries-Heje MM ，Nielsen PB ，Knudsen AD ，Fogh K ，Norsk JB ，Andersen O ，Jensen CAJ ，Torp-Pedersen C ，Rungby J ，Ditlev SB ，Hageman I ，Møgelvang R ，Dessau RB ，Sørensen E ，Harritshøj LH ，Folke F ，Sten C ，Møller MEE ，Engsig FN ，Ullum H ，Jørgensen CS ，Ostrowski SR ，Bundgaard H ，Iversen KK ，Fischer TK ，Nielsen SD ... -  《Microbiology Spectrum》

Characteristics of Anti-SARS-CoV-2 Antibodies in Recovered COVID-19 Subjects.

Huynh A ，Arnold DM ，Smith JW ，Moore JC ，Zhang A ，Chagla Z ，Harvey BJ ，Stacey HD ，Ang JC ，Clare R ，Ivetic N ，Chetty VT ，Bowdish DME ，Miller MS ，Kelton JG ，Nazy I ... -  《Viruses-Basel》

Quantitative SARS-CoV-2 Serology in Children With Multisystem Inflammatory Syndrome (MIS-C).

We aimed to measure severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological responses in children hospitalized with multisystem inflammatory syndrome in children (MIS-C) compared with those with coronavirus disease 2019 (COVID-19), those with Kawasaki disease (KD), and hospitalized pediatric controls. From March 17, 2020, to May 26, 2020, we prospectively identified hospitalized children with MIS-C (n = 10), symptomatic COVID-19 (n = 10), and KD (n = 5) and hospitalized controls (n = 4) at Children's Healthcare of Atlanta. With institutional review board approval, we obtained prospective and residual blood samples from these children and measured SARS-CoV-2 spike receptor-binding domain (RBD) immunoglobulin M and immunoglobulin G (IgG), full-length spike IgG, and nucleocapsid protein antibodies using quantitative enzyme-linked immunosorbent assays and SARS-CoV-2 neutralizing antibodies using live-virus focus-reduction neutralization assays. We statistically compared the log-transformed antibody titers among groups and performed linear regression analyses. All children with MIS-C had high titers of SARS-CoV-2 RBD IgG antibodies, which correlated with full-length spike IgG antibodies (R 2 = 0.956; P < .001), nucleocapsid protein antibodies (R 2 = 0.846; P < .001), and neutralizing antibodies (R 2 = 0.667; P < .001). Children with MIS-C had significantly higher SARS-CoV-2 RBD IgG antibody titers (geometric mean titer 6800; 95% confidence interval 3495-13 231) than children with COVID-19 (geometric mean titer 626; 95% confidence interval 251-1563; P < .001), children with KD (geometric mean titer 124; 95% confidence interval 91-170; P < .001), and hospitalized controls (geometric mean titer 85; P < .001). All children with MIS-C also had detectable RBD immunoglobulin M antibodies, indicating recent SARS-CoV-2 infection. RBD IgG titers correlated with the erythrocyte sedimentation rate (R 2 = 0.512; P < .046) and with hospital (R 2 = 0.548; P = .014) and ICU lengths of stay (R 2 = 0.590; P = .010). Quantitative SARS-CoV-2 serology may have a role in establishing the diagnosis of MIS-C, distinguishing it from similar clinical entities, and stratifying risk for adverse outcomes.

Rostad CA ，Chahroudi A ，Mantus G ，Lapp SA ，Teherani M ，Macoy L ，Tarquinio KM ，Basu RK ，Kao C ，Linam WM ，Zimmerman MG ，Shi PY ，Menachery VD ，Oster ME ，Edupuganti S ，Anderson EJ ，Suthar MS ，Wrammert J ，Jaggi P ... -  《-》

Mild SARS-CoV-2 Illness Is Not Associated with Reinfections and Provides Persistent Spike, Nucleocapsid, and Virus-Neutralizing Antibodies.

Schuler CF 4th ，Gherasim C ，O'Shea K ，Manthei DM ，Chen J ，Zettel C ，Troost JP ，Kennedy AA ，Tai AW ，Giacherio DA ，Valdez R ，Baldwin JL ，Baker JR Jr ... -  《Microbiology Spectrum》