5 ms·
No, it is impossible to reach herd immunity if Reff >= 1, but Reff < 1 is not sufficient for herd immunity. Herd immunity also means low enough incidence that a
by empthought 5y ago
No, it is impossible to reach herd immunity if Reff >= 1, but Reff < 1 is not sufficient for herd immunity. Herd immunity also means low enough incidence that a nonimmune person is not at significantly greater risk than an immune person.
Hence, “herd” immunity.
- dannyz 5y agoHerd immunity would usually be defined as: if a contagion is introduced to a community will it spread uncontrolled or will it die off. Reff < 1 implies it will die off, Reff > 1 implies it will spread. Herd immunity does not mean that the contagion is not present within the community or anything about the relative risk between immune/non-immune community members.