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-an example of vaccines oversimplification, bad science -this "explorable" is full of mistakes and errors: *This explorable illustrates the mechanism of herd immunity. When an infectious disease spreads in a population, an individual can be protected by a vaccine that delivers immunity. But there's a greater good. Immunization not only projects the individual directly. The immunized person will also never transmit the disease to others, effectively reducing the likelihood that the disease can proliferate in the population. Because of this, a disease can be eradicated even if not the entire population is immunized. This population wide effect is known as herd immunity. * http://www.complexity-explorables.org/explorables/herd/ -1/ "The system is initially fully susceptible with a few infected individuals randomly scattered into the population". Usually, many individuals without the vaccination are not susceptible, but immunized because the natural infection. -2/ "An infected individual remains infectious for some time, recover subsequently, and become susceptible again". In many cases, an infected individual recover subsequently, and become protected for the whole life. -3/ "The immunized person will also never transmit the disease to others" In some case yes, in others no. See the diphtheria vaccine. Vaccinated individuals can carrier toxigenic diphtheria germs and transmit the disease to others. -4/ In most cases (except perhaps for the vaccine of yellow fever) "inmunity" is not for ever. Most vaccines simply delaye the "window" for infections (they are time bombs). This is the case of measles vaccine and why in New Zealdand will add a supplementary (3rd shot) https://www. sciencedirect.com/science/article/pii/S0264410X17310034 … <https://t.co/516hwI1hh3> -the author could help readers with a "note" as: "This a theoretical situation. In practice the situation of the naive American indians when the Spaniards arrived with measles, for example (a new disease in America). [but at that time we have no measles vaccine] Or, when developing a vaccine against gonorrhea, where a protective immune response is absent (by contrast syphilis infection produces a partially protective immunity) https://www.nature.com/articles/nature03072 … <https://t.co/SMSs4lrXq4> " -it is not so simple. Herd immunity. Measles. The 95% coverage mantra. Measles outbreak with more than 97% coverage (Navarra, Spain; Porto, Portugal; Gothenburg, Sweden http://crofsblogs.typepad.com/h5n1/2018/01/s weden-measles-outbreak-also-affects-vaccinated.html … <https://t.co/QnM7n7YG6v> And many vaccines have no heard inmunity at all: tetanus, rabies, diphtheria,... -un saludo juan gérvas @JuanGrvas ######################################################################## To unsubscribe from the EVIDENCE-BASED-HEALTH list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1