3 ms·
I think you are referring to ADE (antibody dependent enhancement). This is a function of the vaccine, not the virus. The idea here it to use a strain you know i
by danieltillett 6y ago
I think you are referring to ADE (antibody dependent enhancement). This is a function of the vaccine, not the virus. The idea here it to use a strain you know is safer than one you know is more dangerous.
For a challenge trial you only need enough virus for a few thousand people at most. It is not difficult to produce this amount of virus in cell culture.
- Gatsky 6y agoYes although antibodies aren’t the only mechanism. I’m not worried about post-vaccine enhancement with the attenuated strain, I’m worried that you can’t reliably demonstrate the vaccine doesn’t cause enhancement after the real infection.
- danieltillett 6y agoThis problem exists with or without finding an attenuated strain. A better way to think about this is let’s say we had two strains of the virus isolated - one that killed 10% of people infected and the other that killed less than 0.0001%. Which one should we use in a challenge trial?
- Gatsky 6y agoI’m not sure what your point is. Ultimately you need to demonstrate a vaccine is safe and efficacious for the real disease. An attenuated strain isn’t the real disease.
- danieltillett 6y agoNo you don’t if you choose the right attenuated strain, but even if you decided for some insane reason that you had to test the vaccine with a pathogenic strain you do this after you have shown that the vaccine protected the vaccinated person from the attenuated strain.
- Gatsky 6y agoHow do you know you’ve chosen the right attenuated strain?
- lbeltrame 6y agoFTR, at least the preprint written by SinoVac about their inactivated vaccine (which is in Phase 1, and Phase 2 beginning shortly IIRC), claims that they observed no ADE in rhesus macaques.