Repeated cross-sectional sero-monitoring of SARS-CoV-2 in New York City.

In late 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first detected in China and has since caused a pandemic of coronavirus disease 2019 (COVID-19). The first case of COVID-19 in New York City was officially confirmed on 1 March 2020 followed by a severe local epidemic1. Here, to understand seroprevalence dynamics, we conduct a retrospective, repeated cross-sectional analysis of anti-SARS-CoV-2 spike antibodies in weekly intervals from the beginning of February to July 2020 using more than 10,000 plasma samples from patients at Mount Sinai Hospital in New York City. We describe the dynamics of seroprevalence in an 'urgent care' group, which is enriched in cases of COVID-19 during the epidemic, and a 'routine care' group, which more closely represents the general population. Seroprevalence increased at different rates in both groups; seropositive samples were found as early as mid-February, and levelled out at slightly above 20% in both groups after the epidemic wave subsided by the end of May. From May to July, seroprevalence remained stable, suggesting lasting antibody levels in the population. Our data suggest that SARS-CoV-2 was introduced in New York City earlier than previously documented and describe the dynamics of seroconversion over the full course of the first wave of the pandemic in a major metropolitan area.

Safety and immunogenicity of mRNA-based seasonal influenza vaccines formulated to include multiple A/H3N2 strains with or without the B/Yamagata strain in US adults aged 50-75 years: a phase 1/2, open-label, randomised trial.

BACKGROUND: Inclusion of additional influenza A/H3N2 strains in seasonal influenza vaccines could expand coverage against multiple, antigenically distinct, cocirculating A/H3N2 clades and potentially replace the no longer circulating B/Yamagata strain. We aimed to evaluate the safety and immunogenicity of three next-generation seasonal influenza mRNA vaccines with different compositions that encode for haemagglutinins of multiple A/H3N2 strains, with or without the B/Yamagata strain, in adults. METHODS: This randomised, open-label, phase 1/2 trial enrolled healthy adults aged 50-75 years across 22 sites in the USA. Participants were randomly assigned (1:1:1:1:1:1:1) via interactive response technology to receive a single dose of mRNA-1011.1 (pentavalent; containing one additional A/H3N2 strain [Newcastle]), mRNA-1011.2 (quadrivalent; B/Yamagata replaced with one additional A/H3N2 strain [Newcastle]), mRNA-1012 at one of two dose levels (pentavalent; B/Yamagata replaced with two additional A/H3N2 strains [Newcastle and Hong Kong]), or one of three quadrivalent mRNA-1010 controls each encoding one of the A/H3N2 study strains. The primary outcomes were safety, evaluated in all randomly assigned participants who received a study vaccination (safety population), and reactogenicity, evaluated in all participants from the safety population who contributed any solicited adverse reaction data (solicited safety population). The secondary outcome was humoral immunogenicity of investigational mRNA vaccines at day 29 versus mRNA-1010 control vaccines based on haemagglutination inhibition antibody (HAI) assay in the per-protocol population. Here, we summarise findings from the planned interim analysis after participants had completed day 29. The study is registered with ClinicalTrials.gov, NCT05827068, and is ongoing. FINDINGS: Between March 27 and May 9, 2023, 1183 participants were screened for eligibility, 699 (59·1%) were randomly assigned, and 696 (58·8%) received vaccination (safety population, n=696; solicited safety population, n=694; per-protocol population, n=646). 382 (55%) of the 696 participants in the safety population self-reported as female and 314 (45%) as male. Frequencies of solicited adverse reactions were similar across vaccine groups; 551 (79%) of 694 participants reported at least one solicited adverse reaction within 7 days after vaccination and 83 (12%) of 696 participants reported at least one unsolicited adverse event within 28 days after vaccination. No vaccine-related serious adverse events or deaths were reported. All three next-generation influenza vaccines elicited robust antibody responses against vaccine-matched influenza A and B strains at day 29 that were generally similar to mRNA-1010 controls, and higher responses against additional A/H3N2 strains that were not included within respective mRNA-1010 controls. Day 29 geometric mean fold rises in HAI titres from day 1 against vaccine-matched A/H3N2 strains were 3·0 (95% CI 2·6-3·6; Darwin) and 3·1 (2·6-3·8; Newcastle) for mRNA-1011.1; 3·3 (2·7-4·1; Darwin) and 4·2 (3·4-5·2; Newcastle) for mRNA-1011.2; 3·4 (2·9-4·0; Darwin), 4·5 (3·6-5·5; Newcastle), and 5·1 (4·2-6·2; Hong Kong) for mRNA-1012 50·0 µg; and 2·6 (2·2-3·1; Darwin), 3·7 (3·0-4·6; Newcastle), and 4·1 (3·3-5·1; Hong Kong) for mRNA-1012 62·5 µg. Inclusion of additional A/H3N2 strains did not reduce responses against influenza A/H1N1 or influenza B strains, and removal of B/Yamagata did not affect responses to B/Victoria. INTERPRETATION: These data support the continued clinical development of mRNA-based next-generation seasonal influenza vaccines with broadened influenza A/H3N2 strain coverage. FUNDING: Moderna.

Chimeric hemagglutinin split vaccines elicit broadly cross-reactive antibodies and protection against group 2 influenza viruses in mice.

Seasonal influenza virus vaccines are effective when they are well matched to circulating strains. Because of antigenic drift/change in the immunodominant hemagglutinin (HA) head domain, annual vaccine reformulations are necessary to maintain a match with circulating strains. In addition, seasonal vaccines provide little to no protection against newly emerging pandemic strains. Sequential vaccination with chimeric HA (cHA) constructs has been proven to direct the immune response toward the immunosubdominant but more conserved HA stalk domain. In this study, we show that immunization with group 2 cHA split vaccines in combination with the CpG 1018 adjuvant elicits broadly cross-reactive antibodies against all group 2 HAs, as well as systemic and local antigen-specific T cell responses. Antibodies elicited after sequential vaccination are directed to conserved regions of the HA such as the stalk and the trimer interface and also to the N2 neuraminidase (NA). Immunized mice were fully protected from challenge with a broad panel of influenza A viruses.

Functionality of the putative surface glycoproteins of the Wuhan spiny eel influenza virus.

A panel of influenza virus-like sequences were recently documented in fish and amphibians. Of these, the Wuhan spiny eel influenza virus (WSEIV) was found to phylogenetically cluster with influenza B viruses as a sister clade. Influenza B viruses have been documented to circulate only in humans, with certain virus isolates found in harbor seals. It is therefore interesting that a similar virus was potentially found in fish. Here we characterize the putative hemagglutinin (HA) and neuraminidase (NA) surface glycoproteins of the WSEIV. Functionally, we show that the WSEIV NA-like protein has sialidase activity comparable to B/Malaysia/2506/2004 influenza B virus NA, making it a bona fide neuraminidase that is sensitive to NA inhibitors. We tested the functionality of the HA by addressing the receptor specificity, stability, preferential airway protease cleavage, and fusogenicity. We show highly specific binding to monosialic ganglioside 2 (GM2) and fusogenicity at a range of different pH conditions. In addition, we found limited antigenic conservation of the WSEIV HA and NA relative to the B/Malaysia/2506/2004 virus HA and NA. In summary, we perform a functional and antigenic characterization of the glycoproteins of WSEIV to assess if it is indeed a bona fide influenza virus potentially circulating in ray-finned fish.

SARS-CoV-2 Seroconversion in Humans: A Detailed Protocol for a Serological Assay, Antigen Production, and Test Setup.

In late 2019, cases of atypical pneumonia were detected in China. The etiological agent was quickly identified as a betacoronavirus (named SARS-CoV-2), which has since caused a pandemic. Several methods allowing for the specific detection of viral nucleic acids have been established, but these only allow detection of the virus during a short period of time, generally during acute infection. Serological assays are urgently needed to conduct serosurveys, to understand the antibody responses mounted in response to the virus, and to identify individuals who are potentially immune to re-infection. Here we describe a detailed protocol for expression of antigens derived from the spike protein of SARS-CoV-2 that can serve as a substrate for immunological assays, as well as a two-stage serological enzyme-linked immunosorbent assay (ELISA). These assays can be used for research studies and for testing in clinical laboratories. © 2020 The Authors. Basic Protocol 1: Mammalian cell transfection and protein purification Basic Protocol 2: A two-stage ELISA for high-throughput screening of human serum samples for antibodies binding to the spike protein of SARS-CoV-2.

A serological assay to detect SARS-CoV-2 seroconversion in humans.

Here, we describe a serological enzyme-linked immunosorbent assay for the screening and identification of human SARS-CoV-2 seroconverters. This assay does not require the handling of infectious virus, can be adjusted to detect different antibody types in serum and plasma and is amenable to scaling. Serological assays are of critical importance to help define previous exposure to SARS-CoV-2 in populations, identify highly reactive human donors for convalescent plasma therapy and investigate correlates of protection.