SARS-CoV-2 variants of concern (VOC) are more transmissible and may have the potential
for increased disease severity and decreased vaccine effectiveness. We estimated the …

Knowing vaccine effectiveness (VE) against variants of concern (VOCs) in the real-world
setting is essential for public health decision-making. A systematic landscape of the VE …

Background Vaccinations have reduced severe burden of COVID-19 and allowed for lifting
of non-pharmaceutical interventions. However, with immunity waning alongside emergence …

Background Several countries have authorised or begun using a booster vaccine dose
against COVID-19. Policy makers urgently need evidence of the effectiveness of additional …

Trial results for two COVID-19 vaccines suggest at least 90% efficacy against symptomatic
disease (VEDIS). It remains unknown whether this efficacy is mediated by lowering SARS …

Infectious viral load (VL) expelled as droplets and aerosols by infected individuals partly
determines transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) …

Abstract Background The period from February to June 2021 was one during which initial
wild-type SARS-CoV-2 strains were supplanted in Ontario, Canada, first by variants of …

Background: Between February and June 2021, the initial wild-type strains of SARS-CoV-2
were supplanted in Ontario, Canada, by new variants of concern (VOCs), first those with the …

Background A rapid increase in coronavirus disease 2019 (Covid-19) cases due to the
omicron (B. 1.1. 529) variant of severe acute respiratory syndrome coronavirus 2 in highly …

The emergence of the Omicron variant (B. 1.1. 529) of SARS-CoV-2 has raised concerns
about how mutations in the spike protein might influence immune escape and vaccine …