Measles v Anti-vax
My social media platforms are stuck in an anti-vax algorithm and I'm being shown tons of ragebait anti-vax posts. I know I need to stop interacting with the posts in order for the algorithm(s) to free me of this hell, but I haven't been able to yet — they just keep sucking me in.
Anyway, I see comments like the following about herd immunity:
herd immunity isn't a thing. Or was it just not a covid thing???
This is a comment from someone on a social media post about the measles outbreaks we are experiencing. It seems people are either really confused or blissfully ignorant, so here's my response to this kind of commentary.
Herd immunity requires all three of these to be true: that the virus is spread by human to human contact, does not rapidly mutate, and we have sterilizing immunity (vaccines).
Flu, COVID, norovirus etc. do not have the capability for herd immunity because it only takes just one of those three things to not be true for a pathogen for herd immunity to not work. In this case, rapid mutation is the main issue. The vaccines we make for the flu are usually about ~40% effective at sterilization immunity (preventing influenza) because the flu virus mutates; this is the same case for COVID. The COVID vaccines were not sterilizing vaccines, meaning they were not to prevent being infected by COVID, but are used to decrease the serious complications from the virus — and additionally, COVID mutates rapidly.
Measles, polio, diphtheria, and smallpox are some examples where herd immunity can exist. We have created sterilizing immunity vaccines to prevent infection and these pathogens have been consistently the same for decades and are transmitted by human to human contact.
Pathogens like tetanus we can vaccinate for personal protection, but even if 100% of people have been vaccinated, we can still get tetanus by stepping on a rusty nail as it isn't transmitted person to person — it is environmental only; so this means that herd immunity doesn't work on pathogens like that or animal based vectors like rabies or malaria.
I don't know if anyone will actually read this and think about it, and if you don't, that's fine. Someone else might find it useful.