🧵 Why some vaccines stop transmission & others don’t:
Vaccines that stop transmission are often against viruses that replicate internally first and only then transmit (like measles). So if the vaccine stops internal replication, it stops transmission.
For COVID vaccines…
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For vax against upper respiratory viruses like SARS2, these viruses often don’t require “internal” replication. They just land in the nose, replicate locally & transmit on. So the vax can block “internal” replication and thus stop disease separate from stopping transmission
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The immune response in the upper respiratory tract is somewhat distinct from response in lungs, blood, lymph, etc.
Most vaccines create a multitude of layers of protection that can block a pathogen in lungs, blood, lymph, without offering the same in the nose/mouth/throat
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This is by no means a complete discourse on immunity and differences in transmission vs disease. But this is one reason why a vaccine against a virus like measles will stop spread while a vaccine against SARS2 or flu may not do so as well.
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Also
Above, I was trying to write something that ppl with no science background could understand.
I meant that local replication (for SARS2, within ACE2 expressing cells) is what is required for onward spread without systemic infection as a pre-requisite for onward spread.
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Joseph Hibbeln MD has long researched and advocated for optimizing nutrition, including studying things like seafood consumption in pregnancy and role of mercury consumption and whether it is linked to autism. Generally he’s come out saying it’s not.
Summary: No evidence of anti science or anti vaccine. Likely very balanced and nuanced rigorous scientist to serve on ACIP.Â
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Cody Meissner MD
Is a pediatric infectious disease expert at my Alma mater - Dartmouth. He is a rigorous scientist and has defended vaccines while formally recognizing underlying issues that are causing people to turn away from them - such as vaccine success driving down disease - affording people the luxury of focusing on very rare side effects while forgetting the real impacts of the diseases.Â
One of the most common tropes is that measles is fine & doesn’t cause damage…
This is highly inaccurate
Measles literally grows by infecting and killing memory immune cells. It causes loss to existing immunity creating vulnerabilities & acute damage that is often severe
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To discover the massive-stealth-impact measles has on immune protection against infections not associated w measles, we looked at what happened in populations after measles outbreaks swept through, decade after decade across nations…