RESUMEN
The global distribution and ongoing evolution of type A swine influenza virus (IAV-S) continue to pose significant challenges against developing broadly protective vaccines to control swine influenza. This study focuses on the hemagglutinin (HA) consensus-based approach towards developing a more broadly protective swine influenza vaccine against various H3 strains circulating in domestic pig populations. By computationally analyzing >1000 swine H3 full-length HA sequences, we generated a consensus H3 and expressed it in the context of influenza A WSN/33 reverse genetics system. The derived recombinant chimeric swine influenza virus with the consensus H3 was inactivated and further evaluated as a potential universal vaccine in pigs. The consensus H3 vaccine elicited broadly active hemagglutination inhibition (HI) antibodies against divergent swine H3N2 influenza viruses including human H3N2 variant of concern, and strains belong to genetic clusters IV, IV-A, IV-B, IV-C, IV-D and IV-F. Importantly, vaccinated pigs were completely protected against challenge with a clinical swine H3N2 isolate in that neither viral shedding nor replication in lungs of vaccinated pigs were observed. These findings warrant further study of the consensus H3 vaccine platform for broad protection against diverse swine influenza viruses.
RESUMEN
The objective of this longitudinal cohort study was to determine the seroprevalence of antibodies to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in healthcare workers employed at healthcare settings in three rural counties in eastern South Dakota and western Minnesota from May 13, 2020, through December 22, 2020. Three blood draws were performed at five clinical sites and tested for the presence of antibodies against the SARS-CoV-2. Serum samples were tested for the presence of antibodies using a fluorescent microsphere immunoassay (FMIA), neutralization of SARS-CoV-2 spike-pseudotyped particles (SARS-CoV-2pp) assay, and serum virus neutralization (SVN) assay. The seroprevalence was determined to be 1/336 (0.29%) for samples collected from 5/13/20 to 7/13/20, 5/260 (1.92%) for samples collected from 8/13/20 to 9/25/20, and 35/235 (14.89%) for samples collected from 10/16/20 to 12/22/20. Eight of the 35 (22.8%) seropositive individuals identified in the final draw did not report a previous diagnosis with COVID-19. There was a high correlation (>90%) between the FMIA and virus neutralization assays. Each clinical site's seroprevalence was higher than the cumulative incidence for the general public in the respective county as reported by state public health agencies. As of December 2020, there was a high percentage (85%) of seronegative individuals in the study population.