Heterologous infection and vaccination shapes immunity against SARS-CoV-2 variants

Immune imprinting For severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), immune responses to heterologous variants are influenced by a person’s infection history. Healthcare workers (HCWs) may be exposed to several doses and types of antigens, either by natural infection or by vaccination. Reynolds et al . studied a cohort of UK HCWs followed since March 2020. The immunological profiles of these people depended on how often the subject had encountered antigen and which variant was involved. Vaccine responses after infection were found to be less effective if the infection involved heterologous spike from a variant virus. Unfortunately, the N501Y spike mutation, found in many variants, seems to induce the regulatory T cell transcription factor FOXP3, indicating that the virus could subvert effective T cell function. Changes to antibody binding between variants also means that serology data using the Wuhan Hu-1 S1 receptor-binding domain sequence may not be a reliable measure of protection. —CA

The Molecular Determinants of Antigenic Drift in a Novel Avian Influenza A (H9N2) Variant Virus

Background: In early 2020, a novel H9N2 AIV immune escape variant emerged in South China and rapidly spread throughout mainland China. The effectiveness of the current H9N2 vaccine is being challenged by emerging immune escape strains. Assessing key amino acid substitutions that contribute to antigenic drift and immune escape in the HA gene of circulating strains is critical for understanding virus evolution and in selecting more effective vaccine components. Methods: In this study, a representative immune escape strain, A/chicken/Fujian/11/2020 (FJ/20), differed from current H9N2 vaccine strain, A/chicken/Anhui/LH99/2017 (AH/17) by 18 amino acids in the head domain. To investigate the molecular determinants of antigenic drift of FJ/20, a panel of mutants were generated by reverse genetics including specific amino acids changes in the HA genes of FJ/20 and AH/17. The antigenic effect of the substitutions was evaluated by hemagglutination inhibition (HI) assay and antigenic cartography. Results: Fujian-like H9N2 viruses had changed antigenicity significantly, having mutated into an antigenically distinct sub-clade. Relative to the titers of the vaccine virus AH/17, the escape strain FJ/20 saw a 16-fold reduction in HI titer against antiserum elicited by AH/17. Our results showed that seven residue substitutions (D127S, G135D, N145T, R146Q, D179T, R182T and T183N) near the HA receptor binding sites were critical for converting the antigenicity of both AH/17 and FJ/20. Especially, the combined mutations 127D, 135G, 145N, and 146R could be a major factor of antigenic drift in the current immune escape variant FJ/20. The avian influenza A (H9N2) variant virus need further ongoing epidemiological surveillance.Conclusions: In this study, we evaluated the relative contributions of different combinations of amino acid substitutions in the HA globular head domain of the immune escape strain FJ/20 and the vaccine strain AH/17. Our study provides more insights into the molecular mechanism of the antigenic drift of the H9N2 AIV immune escape strain. This work identified important markers for understanding H9N2 AIV evolution as well as for improving vaccine development and control strategies in poultry.

Antibody Responses to 3rd Dose mRNA Vaccines in Nursing Home and Assisted Living Residents

A comparison of SARS-CoV-2 wild-type and the beta variant virus neutralization capacity between 2 and 3 mRNA vaccine series in nursing home residents, and between nursing home and assisted living residents strongly supports 3rd dose vaccine recommendations, and equivalent polices for nursing homes and assisted living settings. Findings suggest that residents mount a robust humoral response to a 3rd mRNA vaccination, and have greater neuralization capacity compared to a 2 dose series.

Use of eVLP-based vaccine candidates to broaden immunity against SARS-CoV-2 variants

Rapid emergence of SARS-CoV-2 variants is a constant threat and a major hurdle to reach heard immunity. We produced VBI-2905a, an enveloped virus-like particules (eVLP)-based vaccine candidate expressing prefusion spike protein from the Beta variant that contains several escape mutation. VBI-2905a protected hamsters against infection with a Beta variant virus and induced high levels of neutralizing antibodies against Beta RBD. In a heterologous vaccination regimen, a single injection of VBI-2905a in animals previously immunized with VBI-2902, a vaccine candidate expressing S from ancestral SARS-CoV-2, hamsters were equally protected against Beta variant infection. As an alternate strategy to broaden immunity, we produced a trivalent vaccine expressing the prefusion spike protein from SARS-CoV-2 together with unmodifed S from SARS-CoV-1 and MERS-CoV. Relative to immunity induced against the ancestral strain, the trivalent vaccine VBI-2901a induced higher and more consistent antibody binding and neutralizing responses against a panel of variants including Beta, Delta, Kappa, and Lambda, with evidence for broadening of immunity rather than just boosting cross-reactivity antibodies.

Isothermal amplification and fluorescent detection of SARS-CoV-2 and SARS-CoV-2 variant virus in nasopharyngeal swabs

The COVID-19 pandemic caused by the SARS-CoV-2 is a serious health threat causing worldwide morbidity and mortality. Real-time reverse transcription PCR (RT-qPCR) is currently the standard for SARS-CoV-2 detection. Although various nucleic acid-based assays have been developed to aid the detection of SARS-CoV-2 from COVID-19 patient samples, the objective of this study was to develop a diagnostic test that can be completed in 30 minutes without having to isolate RNA from the samples. Here, we present an RNA amplification detection method performed using reverse transcription loop-mediated isothermal amplification (RT-LAMP) reactions to achieve specific, rapid (30 min), and sensitive (<100 copies) fluorescent detection in real-time of SARS-CoV-2 directly from patient nasopharyngeal swab (NP) samples. When compared to RT-qPCR, positive NP swab samples assayed by fluorescent RT-LAMP had 98% (n = 41/42) concordance and negative NP swab samples assayed by fluorescent RT-LAMP had 87% (n = 59/68) concordance for the same samples. Importantly, the fluorescent RT-LAMP results were obtained without purification of RNA from the NP swab samples in contrast to RT-qPCR. We also show that the fluorescent RT-LAMP assay can specifically detect live virus directly from cultures of both SARS-CoV-2 wild type (WA1/2020), and a SARS-CoV-2 B.1.1.7 (alpha) variant strain with equal sensitivity to RT-qPCR. RT-LAMP has several advantages over RT-qPCR including isothermal amplification, speed (<30 min), reduced costs, and similar sensitivity and specificity.

Isolation of SARS-CoV-2 B.1.1.28.2 P2 variant and pathogenicity comparison with D614G variant in hamster model

Background: Considering the potential threat from emerging SARS-CoV-2 variants and the rising COVID-19 cases, SARS-CoV-2 genomic surveillance is ongoing in India. We report herewith the isolation of the P.2 variant (B.1.1.28.2) from international travelers and further its pathogenicity evaluation and comparison with D614G variant (B.1) in hamster model. Methods: Virus isolation was performed in Vero CCL81 cells and genomic characterization by next generation sequencing. The pathogenicity of the isolate was assessed in Syrian hamster model and compared with B.1 variant. Results: B.1.1.28.2 variant was isolated from nasal/throat swabs of international travelers returned to India from United Kingdom and Brazil. The B.1.1.28.2 variant induced body weight loss, viral replication in the respiratory tract, lung lesions and caused severe lung pathology in infected Syrian hamster model in comparison, with B.1 variant infected hamsters. The sera from B.1.1.28.2 infected hamsters efficiently neutralized the D614G variant virus whereas 6-fold reduction in the neutralization was seen in case of D614G variant infected hamsters sera with the B.1.1.28.2 variant. Conclusions: B.1.1.28.2 lineage variant could be successfully isolated and characterization could be performed. Pathogenicity of the isolate was demonstrated in Syrian hamster model and in comparison, with B.1 variant was found more pathogenic. The findings of increased disease severity and neutralization reduction is of great concern and point towards the need for screening the vaccines for efficacy.

IMPLEMENTATION OF VISA SERVICES AS IMMIGRATION POLICY DURING PANDEMIC OF COVID-19

At the end of 2019, the world was shocked by the invention of a new variant virus in Wuhan, laternamed Covid-19. This case has become a particular concern to the world, especially WHO, because the virus can cause fatalities, and the rate of transmission is very fast. Shortly after the invention, WHO declared Covid19 as a global pandemic. Each country is doing their best to prevent the Covid-19 virus from entering their country's territory, including in Indonesia. The Indonesian government then creates policies from all aspectsand fields to prevent and break thetransmission chain of Covid-19 cases. One of the fieldsthat played a roleis Immigration.Directorate General of Immigration, as one of the authorized institutions in the field of Immigration,has authority over all activities of people who entering and exiting the territory of Indonesia. During this Covid-19 pandemic, Indonesian Immigration has created new policies. One of the policies thathave been created is the policy about Visa services that are provided and applied to Foreign Nationals who will enter and stay in Indonesia. Immigration policy related to visas is continuously updated and applied according to the situation, conditions, and policies of the government to achieve one goal, which is preventing and breaking the transmission chain of Coronavirus in Indonesia.

Qualitative Case Study of Public Health Preparedness and Response to the Rabid Raccoon Discovered in Wise County, Virginia

Rabies is a zoonotic lyssavirus of mammals that is a major public health threat due to the high mortality rate in humans who develop clinical symptoms. In the United States and other developed countries, the main reservoirs are wildlife species. In April 2017, a raccoon tested positive for rabies in Wise County, Virginia, with a second raccoon testing positive in May. Wise County, Virginia, is one of the few counties in western Virginia that is not endemic for raccoon rabies variant virus. Due to this fact, local, state, and federal agencies worked together to prevent and control the outbreak to stop the public health theat. The purpose of this study was to understand how professionals from these various agencies viewed the response efforts to the two rabid raccoons in 2017 and to determine what could be done to improve future responses. A list of responders from the different agencies involved in the outbreak in 2017 was created. Participants were recruited via email and those who agreed to be interviewed were contacted via telephone. Participants were asked a series of 13 questions pertaining to the 2017 outbreak to understand more about the strengths and weaknesses perceived during the outbreak. Of the 11 individuals contacted, six agreed to an interview. Data were analyzed utilizing a three-step qualitative analysis process which included the steps of open coding, audit trail, and axial coding. Staff and partnerships were identified as strengths of the response while funding, community, and region were identified as weaknesses of the response. It is hoped that by identifying different strengths and weaknesses through qualitative analysis this will aid in improving future responses.