In 1923 , University of Manchester bacteriologist W.W.C. Topley and G.S. Wilson strike the phraseherd immunityin a study of how bacterial contagion spread through a group of computer mouse when some had been inoculated [ PDF ] . Though they stress that further inquiry was take on the subject , the basic thought was that a community might be able to accomplish overall protection from an infectious disease if a sure symmetry of its individual members were resistant .
If , for example , a sick individual came in contact with five people — four of whom were immune to the disease — that someone could only pass it on to the one susceptible individual . Not only would the other four masses remain healthy , but they also would n’t transmit the disease to whomever they encountered . This way , curious case are much easy to bear , and a highly infectious disease becomes a much down in the mouth threat to an intact residential area .
Nearly a C after Topley and Wilson insert the term , humankind have seen ruck exemption play out in real living more than a few times . As the Association for Professionals in Infection Control and Epidemiologyexplains , it often go on when the absolute majority of a population gets immunize against a certain disease . It ’s still potential to contract chicken lues ormeasles , for example , but so many people in the U.S. have received thosevaccinesthat individual cases do n’t easy become outbreaks ( orpandemics ) .
ruck immunity can also happen when many individuals have already contract a disease and now own antibodies that make them resistant to catching it again . Since we do n’t have a vaccinum forCOVID-19yet , some multitude are skip we can accomplish herd immunity this elbow room . Butaccording toGypsyamber D’Souza and David Dowdy , epidemiologyprofessors at the Johns Hopkins Bloomberg School of Public Health , recovered COVID-19 patient role might only be immune to the disease “ for months to years . ” We do n’t currently have enough information to recognize how reinfection works with this finicky coronavirus , but we do know people can be reinfected with other coronaviruses . In other words , we should n’t count on achieving herd immunity in this personal manner .
moreover , it ’s estimated that at least 70 pct of somebody would ask immunity to COVID-19 in order for the whole population to have ruck immunity . Our healthcare system would quickly become overwhelmed with the number of case and catastrophic number of deaths that would occur if people designedly became infected to achieve immunity .
To summarise : Our best bet for conquer COVID-19 is to social - distance , wear amask , and waitress patiently for a vaccinum .
[ h / tJohns Hopkins Bloomberg School of Public Health ]
