| > The article you linked first assumes only one or two antibodies. Assumes only a couple of neutralizing antibodies, which is fair for the vaccine candidates-- immune assays of Moderna's vaccine show two typical antibody binding sites against the RBD that are strongly neutralizing. I haven't seen the ELISA data for Pfizer's vaccine. Given that we've got several papers describing how immune escape variants of other viruses have emerged in the past... I'm curious why you don't think it's much of a risk here? e.g. https://pubmed.ncbi.nlm.nih.gov/11410701/ > As I said before, there is some pressure for antibodies, but the immune system is way more than that, and people can clear infections very effectively without any antibodies at all. Of course. I'm not speculating that there's going to be some nasty variant that completely eludes our immune response. I'm saying that it is likely-- and the consensus opinion-- that there is a real risk that the virus mutates to render the vaccine less effective. > Further research has shown that this variant does not seem to increase disease severity, and instead is just more infectious, as the spike protein evolved for higher binding affinity. Some of the mutations slightly increase binding affinity. Other deletions look like their primary fitness advantage is immune escape. A missing stop-codon also increases mutation rates for a portion of the RBD, which implies we can expect quicker emergence of subvariants. It's like you're having an argument I never was having: I have never said that this is likely to cause more severe disease. I am just saying that the virus will be under selective pressure to evade the vaccine-induced immune responses-- which is something I think everyone agrees. This is less likely to happen if there's less infection around and people get vaccinated quicker. Even in the worst case, where such a variant evolves quickly-- I don't think we're that bad off. As you mention, there's other immune responses. Strong T cell mediated immunity will almost certainly be cross-reactive and strongly reduce the risk of severe illness. We'll have more time to adjust vaccines without mortality accruing as quickly. It is still something we'd prefer to avoid at all costs. |
The answer to this is very probably no. There is a huge difference between the virus making the vaccine less effective eventually, the virus making the vaccine less effective within one to three months, and the virus making the vaccine sufficiently less effective that it can sustain an epidemic among vaccinated individuals. The second is not very likely at all, because for it to happen a variant of the virus would have to mutate, and outcompete the dominant variant, that has a spike protein sufficiently different that it can keep R>1 among vaccinated individuals.
For this, the virus would not only have to evade antibody response sufficiently for there to not be sterilizing immunity, but it would have to do evade the much swifter and effective non-serological immune response enough to stay infectious.
All of this would have to happen in a subset of the population that has a 20x lower chance of being infected and even when that happens, the infection would be much shorter with most of it with completely different evolutionary pressures.
In one to three months.
It would also have to compete effectively against other variants in the non-vaccinated population while it is doing so, because non-vaccinated people are by very far the dominant infection vector. So it would have to evolve this not only in vaccinated, but also non-vaccinated patients, unless you believe that these extensive mutations will happen in one, vaccinated, patient, which is pretty much impossible.