This figure shows number of people weekly who completed their initial vaccination regimen or received booster shot. Ribbon plots represent results from backcasting analysis while dots represent actual data.

Population immunity is estimated as reduction in the absolute risk of becoming infected (blue), symptomatically infected (purple) or severely infected(red) compared to a naive population, for selected viral variants over time (left panel). Some conditional risk reductions are shown in the right panel.

Invasion potential is the level of social distancing required to prevent the communal spread of a new variant (i.e. maintain Rt<1). Social distancing is the reduction in transmission by individuals in the population, a value of 0.10 could mean that everyone contacts 10% fewer people on average than prior to the start of the pandemic, or takes other steps, such as masking or maintaining six feet of space, that decrease the potential for spread by around 10%. Since the start of the pandemic, we estimate that the “new normal” entails about a 20-30% reduction in transmission due solely to behavior. Therefore if less than 20% social distancing is required (green region), a new variant is unlikely to spread. On the other hand, social distancing greater than 50% has not proven feasible so an invading variant whose characterestics put it into the red region will very likely spread.

Modeled prevalence of SARS-CoV-2 antibodies compared to CDC data. To validate our model we check the predicted level of seroprevalence from our model (blue) against data from CDC commercial lab data(grey). These antibody surveys measure anti-nucleocapsid antibodies, which are only generated by infection and not vaccination.

Force of infection by age group is defined as the weekly incidence in a completely uninfected and unvaccinated population, caused by different viral variants over time.

Force of infection for a selected pair of age group and variant is defined as the weekly incidence in a completely uninfected and unvaccinated population, caused by the selected viral variant over time.

This figure shows number of people weekly who completed their initial vaccination regimen or received booster shot. Ribbon plots represent results from backcasting analysis while dots represent actual data.

Population immunity is estimated as reduction in the absolute risk of becoming infected (blue), symptomatically infected (purple) or severely infected(red) compared to a naive population, for selected viral variants over time (left panel). Some conditional risk reductions are shown in the right panel.

Invasion potential is the level of social distancing required to prevent the communal spread of a new variant (i.e. maintain Rt<1). Social distancing is the reduction in transmission by individuals in the population, a value of 0.10 could mean that everyone contacts 10% fewer people on average than prior to the start of the pandemic, or takes other steps, such as masking or maintaining six feet of space, that decrease the potential for spread by around 10%. Since the start of the pandemic, we estimate that the “new normal” entails about a 20-30% reduction in transmission due solely to behavior. Therefore if less than 20% social distancing is required (green region), a new variant is unlikely to spread. On the other hand, social distancing greater than 50% has not proven feasible so an invading variant whose characterestics put it into the red region will very likely spread.

Modeled prevalence of SARS-CoV-2 antibodies compared to CDC data. To validate our model we check the predicted level of seroprevalence from our model (blue) against data from CDC commercial lab data(grey). These antibody surveys measure anti-nucleocapsid antibodies, which are only generated by infection and not vaccination.

Force of infection by age group is defined as the weekly incidence in a completely uninfected and unvaccinated population, caused by different viral variants over time.

Force of infection for a selected pair of age group and variant is defined as the weekly incidence in a completely uninfected and unvaccinated population, caused by the selected viral variant over time.