In COVID-19 clinical update #49, Daniel Griffin discusses CDC guidelines on mask use, drop in test frequency in the US, resurgence of COVID-19 in Brazil, possible impact of Pfizer vaccine on viral load, EUA for bamlanivimab and etesevimab administered together, and preliminary results of Tocilizumab in hospitalized patients.

Theodora and Paul return to TWiV to explain how they quickly pivoted their retrovirus laboratories towards SARS-CoV-2, their work on the antibody response to infection and its durability, and the emergence of variants with increased resistance to neutralization.

In COVID-19 clinical update #48, Daniel Griffin reviews effect of spike amino acid changes on neutralization with monoclonal antibodies, Sputnik V safety and efficacy results, increased reactogenicity after a single vaccine dose in seropositive individuals, single dose vaccination in seropositive health care workers, and results of three clinical trials on the use of anticoagulants.

TWiV explains why hydroxychloroquine failed in humans despite showing antiviral effects in cells, and reviews the published data on the Pfizer/BioNTech mRNA vaccine.

The TWiVers review Biden’s national strategy for COVID-19 responses and pandemic preparedness, and an evaluation of the BinaxNOW rapid antigen test for SARS-CoV-2 infection.

In COVID-19 clinical update #46, Daniel Griffin discusses the BinaxNow rapid antigen test, efficacy of Bamlanivimab in nursing homes, associations of serum vitamin D concentrations with in-hospital mortality and need for invasive mechanical ventilation, trials of IL-6 receptor antagonists, effects of anticoagulants on in-hospital mortality, and symptom persistence in outpatients.