Science

"The model code provides a flexible scaffolding for studying alternative vaccination scenarios. Notably, the model predicts that once the endemic state is reached, mass vaccination may no longer be necessary to save lives."

"Should the vaccine cause a major reduction in transmission, it might be important to consider strategies that target delivery to older individuals for whom infection can cause higher morbidity and mortality, while allowing natural immunity and transmission to be maintained in younger individuals."

"Additionally, during the transition to endemicity, we need to consider how the immune efficacies depend on primary and secondary infections across ages and how responses differ between vaccination and natural infection."

"The key result from our model framework that explicitly recognizes that functional immunity to reinfection, disease, and shedding are different is that, in contrast with infections that are severe in childhood, SARS-CoV-2 could join the ranks of mild, cold-causing endemic HCoVs in the long run."

"The transition from epidemic to endemic dynamics is associated with a shift in the age distribution of primary infections to lower age groups. This transition may take anywhere from a few years to a few decades, depending on how quickly the pathogen spreads. The rate of spread, measured by R0, is determined by a combination of viral properties and the frequency of social contacts and may therefore be reduced by social distancing."