The TWiV team explains what the Biden report on SARS-CoV-2 origins did not: evidence that the virus came from Nature, not a lab; and reveals new coronaviruses in rodents that inhabit populated areas in southern China.

In COVID-19 clinical update #77, Daniel Griffin discusses children becoming increasingly infected, virological characteristics of infections in vaccinated health care workers, transmission dynamics among close contacts, licensing of Pfizer mRNA vaccine, cost of hospitalization of unvaccinated patients, 29 times higher hospitalization rates in unvaccinated patients, boost in neutralizing antibody potency and breadth by third vaccine dose, and use of J&J vaccine as second dose.

Paul and Theodora return to TWiV to explain their research on determining the number of neutralizing epitopes on the SARS-CoV-2 spike that are recognized by antibodies, and engineering of a polymutant spike with twenty amino acid changes that demonstrates the high genetic barrier to escape from convalescent serum.

In COVID-19 clinical update #76, Daniel Griffin covers association of age and pediatric household transmission, rapid antigen testing in remote communities, shedding of infectious virus in vaccinated individuals, FDA amendment of mRNA vaccine EUA to allow a third dose, new vaccine mandate for NY state, full vaccination suppresses selection of variants, effectiveness of mRNA vaccines in nursing homes, sustained effectiveness of mRNA vaccines against hospitalization, and no benefit from early convalescent serum in high-risk outpatients.

In COVID-19 clinical update #75, Daniel Griffin reviews vaccine effectiveness against transmission, modeling effectiveness of daily antigen tests, updated CDC guidance for fully vaccinated, risk of infection with time after mRNA vaccination, reduced risk of infection after vaccination, therapeutic anticoagulants in critically ill patients, and 6 month outcomes in hospitalized patients.

TWiV reviews SARS-CoV-2 infection of wild white-tailed deer in the US, mRNA vaccine-mediated protection by spike-specific T cells before detection of neutralizing antibodies, and recovery from SARS-CoV-2 infection in T-cell depleted rhesus macaques.

In COVID-19 clinical update #74, Daniel Griffin covers infections in vaccinated individuals, expansion of Regeneron monoclonal antibody cocktail for prophylaxis, neutralization of variants by antibodies produced by infection or vaccination, longer hospital stays associated with remdesivir treatment, and post-acute sequelae of infection and impact on quality of life 1-6 months after illness.

TWiV reviews a leaked CDC document on virulence and spread of the delta variant, and how anti-alphavirus antibodies that do not neutralize infection can nevertheless protect mice from disease.