herd immunity

{
  "id": "MLC-T-ENV-013181",
  "term": "herd immunity",
  "field": "Environment",
  "definition": "1. An estimate of exposure, or dose level received anyone in a defined population that is greater than the 90th percentile of all individuals in that population, but less than the exposure at the highest percentile in that population. A high end risk descriptor is an estimate of the risk level for such individuals. Note that risk is based on a combination of exposure and susceptibility to the stressor.\n\n2. Resistance of a group to a pathogen due to immunity of a large proportion of the group to that pathogen.\n\n3. The resistance of a group to invasion and spread of an infectious agent, based on the resistance to infection of a high proportion of individual members of the group. The resistance is a product of the number susceptible and the probability that those who are susceptible will come into contact with an infected person.\n\n4. Resistance of a group to a pathogen due to immunity of a large proportion of the group to that pathogen. [NLM 2005]\n\n5. The resistance of a group to invasion and spread of an infectious agent, based on the resistance to infection of a high proportion of individual members of the group. The resistance is a product of the number susceptible and the probability that those who are susceptible will come into contact with an infected person. [CDC 2005]\n\n6. The immunity of a group or community. The resistance of a group to invasion and spread of an infectious agent, based on the resistance to infection of a high proportion of individual members of the group. The resistance is a product of the number susceptible and the probability that those who are susceptible will come into contact with an infected person. [MERREA 2005]\n\n7. Situation in which a sufficient proportion of a population is immune to an infectious disease (through vaccination and/or prior illness) to make its spread from person to person unlikely. Even individuals not vaccinated (such as newborns and those with chronic illnesses) are offered some protection because the disease has little opportunity to spread within the community.",
  "subject": "Health and safety",
  "references": [
    "EPA 2005b",
    "NLM 2005",
    "CDC 2005",
    "Thesaurus of Terms Used in Microbial Risk Assessment",
    "CDC Vaccines and Immunizations Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/herd-immunity/"
}