Tridgeridoo
kiwifarms.net
- Joined
- Feb 29, 2020
For reference see Marek's Disease in chicken or the decreasing effectiveness of antibiotics. Again, if you have any more info on why it is different with Covid I'd love to hear it.
Let's look at why Covid is not like Marek's:
1. The Marek's vaccine offers no protection against infection at all. It merely prevents the symptoms.
2. Once infected, birds remain infected for the rest of their lives, and that means vaccinated chickens will continue to shed the virus.
It's easy to see why the conditions are great for new strains, because once a mutation occurs, it's there to stay. Covid is not like that because the vaccine does prevent infection in the majority of cases and because people who are infected will not continue to shed the virus once recovered.
3. Chickens do not travel.
In an unvaccinated population there's a certain selection pressure against highly virulent strains that kill off the host becfore the virus strain can spread. Not being vaccinated does not prevent the spread of more virulent strains that are slow enough to allow the host to spread the new strain before the host dies.
Current Marek strains need 10+ weeks to kill unvaccinated birds. Now ask yourself why a strain like that could evolve and persist in a vaccinated population but not an unvaccinated one. Because chickens do not come into contact with chickens that are not part of their flock. A virus that needs 10+ weeks to kill its host is already too virulent and too lethal to spread to other flocks (via veterinary vists or farms exchanging birds for example), and strains that are too virulent and too lethal will not persist in an unvaccinated population.
But what about humans? How virulent and lethal would a newly mutated Covid strain have to be in order not to be able to spread far and wide in an unvaccinated population that works in offices, travels on aircraft and goes to bars?