You are currently viewing the abstract.AAAS login provides access to Science for AAAS members, and access to other journals in the Science family to users who have purchased individual subscriptions.Log in via OpenAthens.Log in with your institution via Shibboleth.Download and print this article for your personal scholarly, research, and educational use.Buy a single issue of Science for just $15 USD.Injuries to the mammalian spinal cord do not heal easily. Llorens- Bobadilla et al. studied mouse ependymal cells, which function as stem cells for the spinal cord (see the Perspective by Becker...…You are currently viewing the abstract.AAAS login provides access to Science for AAAS members, and access to other journals in the Science family to users who have purchased individual subscriptions.Log in via OpenAthens.Log in with your institution via Shibboleth.Download and print this article for your personal scholarly, research, and educational use.Buy a single issue of Science for just $15 USD.Injuries to the mammalian spinal cord do not heal easily. Llorens- Bobadilla et al. studied mouse ependymal cells, which function as stem cells for the spinal cord (see the Perspective by Becker...WW…

In response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), some politicians have been keen to exploit the idea of achieving herd immunity. Countering this possibility are estimates derived from work on historical vaccination studies, which suggest that herd immunity may only be achieved at an unacceptable cost of lives. Because human populations are far from homogeneous, Britton et al. show that by introducing age and activity heterogeneities into population models for SARS-CoV-2, herd immunity can be achieved at a population-wide infection rate of ∼40%, considerably lower...…In response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), some politicians have been keen to exploit the idea of achieving herd immunity. Countering this possibility are estimates derived from work on historical vaccination studies, which suggest that herd immunity may only be achieved at an unacceptable cost of lives. Because human populations are far from homogeneous, Britton et al. show that by introducing age and activity heterogeneities into population models for SARS-CoV-2, herd immunity can be achieved at a population-wide infection rate of ∼40%, considerably lower...WW…