I've seen various arguments from people who are against vaccinations:-
1. Vaccinated people can still catch the diseases for which they've been vaccinated, therefore vaccinations are ineffective.
2. Vaccinations can damage people.
3. Why are un-vaccinated people a threat? Also, vaccinated people can shed viruses.
4. Morbidity & mortality rates fell dramatically before vaccinations were introduced, therefore vaccinations are unnecessary.
5. Vaccines cause Autism.
1. Vaccination can't stop people from being infected by viruses. What it does is give people a much milder form of the disease so that they produce antibodies to the modified virus.
When vaccinated people are infected with full-strength infectious viruses, their bodies have a much faster immune response to them, much reducing the time taken to destroy them, much reducing morbidity & mortality and much reducing the chance of infecting many others with them. See https://en.wikipedia.org/wiki/Vaccination for more detailed information.
2. As everyone is different, some people don't produce any/enough antibodies to the modified virus and have to be re-vaccinated. Most people produce the correct response, which may make them feel mildly unwell. Some people have a bad reaction to the modified virus, which may make them very ill and in very rare cases may damage them. However, if someone is damaged by a modified virus, a full-strength virus would either damage them much more, or kill them.
If small, known amounts of known antigens entering the body can precipitate Autism, unknown amounts of unknown antigens entering the body due to cuts, grazes, food poisoning and infections would almost certainly have the same effect.
3. EDIT: From https://twitter.com/leoniee54/status/1102880851451248640:-
"Answer to # 3 (why are unvaccinated ppl a threat?): if they go on holidays & (having picked up virus before going) reintroduce disease to countries that haven't had it for 12 years
Disclaimer: I am deaf in one ear due to measles as child before MMR avail."
When un-vaccinated people are infected with full-strength infectious viruses, there's a period of time (the incubation period) during which they shed them and infect many other non-vaccinated people (including immunocompromised people who can't be vaccinated) before antibodies are produced and the immune system destroys them. This is why vaccination rates must be high (higher than 95%, say) in order to achieve "herd immunity", to minimise the risk of full-strength infectious viruses from rapidly spreading through dense populations or other populations due to rapid transportation.
Should modified viruses be shed during the incubation period after vaccination, it's not a problem unless they infect immunocompromised people (who would be much more adversely affected, should they be infected by full-strength viruses).
4. Yes, due to improved health care, but there was still higher morbidity & mortality due to catching full-strength viruses back then than there are now from being vaccinated with modified viruses.
5. Association cannot prove causation.
If A associates with B, the following things are possible.
1. A causes B.
2. B causes A.
3. A and B are caused by C and/or D and/or E etc etc.
4. It's a Spurious correlation.
Randomised Control Trials (RCTs) can prove/disprove causation, but RCTs on human infants wouldn't be approved by ethics committes. RCTs on rhesus macaques infants can be done. See Administration of thimerosal-containing vaccines to infant rhesus macaques does not result in autism-like behavior or neuropathology. Single-dose MMR vaccines haven't contained thimerosal for years, anyway.
See Vaccines and Autism: A Tale of Shifting Hypotheses. If anything....
Disclosure: I have Asperger Syndrome (AS).
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