Impact in the humoral and cellular immune response to SARS-CoV-2 variants after primary vaccination with AZD1222/COVISHIELD protocol in healthy adults.

SARS-CoV-2 emerged rapidly as a pandemic, leading to the urgent development and authorization for the use of several vaccines, with questions relating to immunogenicity in previously infected people or to virus variants. As such, we sought to determine the humoral and cellular immune response of healthy adults to distinct SARS-CoV-2 variants upon AZD1222/COVISHIELD vaccination, using chemiluminescence (CMIA), neutralizing antibody (PRNT) and analysis of activation-induced marker (AIM) by flow cytometry, respectively. We enrolled 75 volunteers, including 26 individuals previously infected with SARS-CoV-2.

Cross-Species Surveillance of Respiratory Viruses in Domestic and Wild Mammals of an Urban Atlantic Forest from Brazil.

Our aim was to investigate respiratory viruses circulating in animals from the urban Atlantic Forest, which is located in the most densely populated area near Rio de Janeiro in Brazil. This study focused on the detection of Influenza A viruses and diverse coronaviruses, including SARS-CoV-2, in domestic and wild animals, including bats, nonhuman primates, rodents, and marsupials. From August 2020 to September 2022, biological samples were collected from a total of 72 pets, 66 primates, 20 rodents, 36 marsupials, and 390 bats.

SARS-CoV-2 Omicron XBB infections boost cross-variant neutralizing antibodies, potentially explaining the observed delay of the JN.1 wave in some Brazilian regions.

Unlabelled: The SARS-CoV-2 JN.1 lineage emerged in late 2023 and quickly replaced the XBB lineages, becoming the predominant Omicron variant worldwide in 2024. We estimate the epidemiologic impact of this SARS-CoV-2 lineage replacement in Brazil and we further assessed the cross-reactive neutralizing antibody (NAb) responses in a cohort of convalescent Brazilian patients infected during 2023.

A Global Collaborative Comparison of SARS-CoV-2 Antigenicity Across 15 Laboratories.

Setting up a global SARS-CoV-2 surveillance system requires an understanding of how virus isolation and propagation practices, use of animal or human sera, and different neutralisation assay platforms influence assessment of SARS-CoV-2 antigenicity. In this study, with the contribution of 15 independent laboratories across all WHO regions, we carried out a controlled analysis of neutralisation assay platforms using the first WHO International Standard for antibodies to SARS-CoV-2 variants of concern (source: NIBSC). Live virus isolates (source: WHO BioHub or individual labs) or spike plasmids (individual labs) for pseudovirus production were used to perform neutralisation assays using the same serum panels.

Timeline kinetics of protective immunity to SARS-CoV-2 upon primary vaccination and humoral response to variants after booster dose.

New variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have emerged, imposing the need for periodic booster doses. However, whether booster doses should be applied to the entire population or groups, and the booster doses interval, remains unclear. In this study, we evaluated humoral reactivity kinetics from before the first dose to 180 days after the third booster dose in different schedules in a well-controlled health worker cohort.

Reduced ability to neutralize the Omicron variant among adults after infection and complete vaccination with BNT162b2, ChAdOx1, or CoronaVac and heterologous boosting.

COVID-19 vaccines have dramatically reduced rates of severe infection requiring hospitalization. However, SARS-CoV-2 variants have reduced vaccine effectiveness at preventing any symptomatic infection. This real-world study analyzed binding and neutralizing antibodies generated after complete vaccination and boosting across three vaccine platforms.

SARS-CoV-2 intra-host diversity, antibody response, and disease severity after reinfection by the variant of concern Gamma in Brazil.

The rapid spread of the SARS-CoV-2 Variant of Concern (VOC) Gamma in Amazonas during early 2021 fueled a second large COVID-19 epidemic wave and raised concern about the potential role of reinfections. Very few cases of reinfection associated with the VOC Gamma have been reported to date, and their potential impact on clinical, immunological, and virological parameters remains largely unexplored. Here we describe 25 cases of SARS-CoV-2 reinfection in Brazil.