Safety and Effectiveness of SA58 Nasal Spray Against COVID-19 Infection in Medical Personnel: An Open-Label, Blank-Controlled Study - Hohhot City, Inner Mongolia Autonomous Region, China, 2022.

What is already known about this topic?: The active ingredient of the SA58 Nasal Spray is a broad-spectrum neutralizing antibody with a high neutralizing capacity against different Omicron sub-variants in vitro studies. What is added by this report?: This study demonstrated the safety and effectiveness of SA58 Nasal Spray against coronavirus disease 2019 (COVID-19) infection in medical personnel for the first time. What are the implications for public health practice?: This study provides an effective approach for the public to reduce their risk of COVID-19 infection. The findings of this research have the potential to significantly reduce the risk of infection and limit human-to-human transmission in the event of a COVID-19 outbreak.

Distinct immune responses in the early phase to natural SARS-CoV-2 infection or vaccination.

Immune responses elicited by viral infection or vaccination play key roles in the viral elimination and the prevention of reinfection, as well as the protection of healthy persons. As one of the most widely used Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, there have been increasing concerns about the necessity of additional doses of inactivated vaccines, due to the waning immune response several months after vaccination. To further optimize inactivated SARS-CoV-2 vaccines, we compared immune responses to SARS-CoV-2 elicited by natural infection and immunization with inactivated vaccines in the early phase. We observed the lower antibody levels against SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in the early phase of postvaccination with a slow increase, compared to the acute phase of SARS-CoV-2 natural infection. Specifically, IgA antibodies have the most significant differences. Moreover, we further analyzed cytokine expression between these two groups. A wide variety of cytokines presented high expression in the infected individuals, while a few cytokines were elicited by inactivated vaccines. The differences in antibody responses and cytokine levels between natural SARS-CoV-2 infection and vaccination with the inactivated vaccines may provide implications for the optimization of inactivated SARS-CoV-2 vaccines and the additional application of serological tests.

Reduced neutralization of SARS-CoV-2 B.1.617 variant by convalescent and vaccinated sera.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The Spike protein that mediates coronavirus entry into host cells is a major target for COVID-19 vaccines and antibody therapeutics. However, multiple variants of SARS-CoV-2 have emerged, which may potentially compromise vaccine effectiveness. Using a pseudovirus-based assay, we evaluated SARS-CoV-2 cell entry mediated by the viral Spike B.1.617 and B.1.1.7 variants. We also compared the neutralization ability of monoclonal antibodies from convalescent sera and neutralizing antibodies (NAbs) elicited by CoronaVac (inactivated vaccine) and ZF2001 (RBD-subunit vaccine) against B.1.617 and B.1.1.7 variants. Our results showed that, compared to D614G and B.1.1.7 variants, B.1.617 shows enhanced viral entry and membrane fusion, as well as more resistant to antibody neutralization. These findings have important implications for understanding viral infectivity and for immunization policy against SARS-CoV-2 variants.

Preclinical Efficacy of IMM-BCP-01, a Highly Active Patient-Derived Anti-SARS-CoV-2 Antibody Cocktail (preprint)

Using an unbiased interrogation of the anti-viral memory B cell repertoire of convalescent COVID-19 patients, we identified three human antibodies that when combined demonstrated both robust viral suppressive properties against all tested SARS-CoV-2 variants of concern in vitro and profound anti-viral efficacy in vivo. In this report, we describe the pre-clinical characterization of an antibody cocktail, IMM-BCP-01, that consists of three unique, patient-derived recombinant antibodies directed at non-overlapping surfaces on the Spike protein, each with particularly effective antiviral activity. One antibody has a composite epitope blocking ACE2 binding, one antibody bridges two Spike proteins, and one antibody neutralizes virus by binding to a conserved epitope outside of ACE2 binding site. These antibodies, when administered after viral infection, potently decreased viral load in lungs of infected Syrian golden hamsters in a dose-dependent manner, elicited broad anti-viral neutralizing activity against multiple SARS-CoV-2 variants, and induced a robust anti-viral effector function response, including phagocytosis, and activation of classical complement pathway. Our pre-clinical data demonstrate that the unique three antibody cocktail IMM-BCP-01 is a potent and dose-efficient approach to treat early viral infection and prevent SARS-CoV-2 in susceptible individuals.

The epidemiological features of pediatric viral respiratory infection during the COVID-19 pandemic in Taiwan.

BACKGROUND: Enhanced nonpharmaceutical interventions (NPIs) to prevent the Coronavirus Disease 2019 (COVID-19) have shown various levels of impact on common respiratory pathogens. We aimed to analyze the epidemiological changes seen in certain common respiratory viruses found in Taiwanese children (e.g., influenza virus, enterovirus, parainfluenza virus, adenovirus and respiratory syncytial virus (RSV)) after the implementation of public health measures, as well as interpret the possible meaning of these changes. METHODS: This retrospective observational study examined the viral isolation from children younger than 18 years at a medical center in central Taiwan during the period January 2015-December 2020, a time frame of six years. Viral isolations prior to the COVID-19 pandemic (January 2015-December 2019), along with those during the post-COVID-19 period (January-December 2020) were analyzed and compared. RESULTS: A total of 6899 throat swab samples were collected during the pre-pandemic period of 2015-2019, with 2681 of them having a positive result (38.86%). There were a total of 713 samples collected in 2020, with 142 of them showing positive results (19.92%). The overall positive rate of viral isolates significantly decreased in 2020 (p < 0.001). Declines in the isolation of the influenza virus, parainfluenza virus, adenovirus and enterovirus were observed. The RSV surprisingly became the leading isolate, with up to 47 (6.59%) instances in 2020, and showing an unusual peak in the winter of 2020. The rise began in September of 2020 and reached its plateau in November of that year. CONCLUSIONS: Most respiratory viruses decreased under NPIs regarding SARS-CoV-2. However, the RSV outbreak in the winter of 2020 had shown the limitation of current NPIs. Possible explanations have been discussed in details and public preventive measures should be reinforced for RSV, particularly amongst people having young children both at home and in care centers.

Immune memory in convalescent patients with asymptomatic or mild COVID-19.

It is important to evaluate the durability of the protective immune response elicited by primary infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we systematically evaluated the SARS-CoV-2-specific memory B cell and T cell responses in healthy controls and individuals recovered from asymptomatic or symptomatic infection approximately 6 months prior. Comparatively low frequencies of memory B cells specific for the receptor-binding domain (RBD) of spike glycoprotein (S) persisted in the peripheral blood of individuals who recovered from infection (median 0.62%, interquartile range 0.48-0.69). The SARS-CoV-2 RBD-specific memory B cell response was detected in 2 of 13 individuals who recovered from asymptomatic infection and 10 of 20 individuals who recovered from symptomatic infection. T cell responses induced by S, membrane (M), and nucleocapsid (N) peptide libraries from SARS-CoV-2 were observed in individuals recovered from coronavirus disease 2019 (COVID-19), and cross-reactive T cell responses to SARS-CoV-2 were also detected in healthy controls.