It is predicated on some dodgy assumptions — principally, that vaccinated individuals still transmit at the same rate as the unvaccinated, that ‘naturally immune’ individuals somehow by contrast do suppress transmission, and that the natural infection route does not select for mutants at the same (or higher) rate.
The biggest problem — and it’s a general one — is the first. I’m sick of seeing people claim that ‘the vaccine does not stop transmission’. It was never definitively demonstrated anyway, despite being widely circulated as categorical truth, and is a common misunderstanding of the scientifically cautious ‘we don’t know if …’. Well, we now have data. The vaccines have all been shown to substantially reduce transmission. If one wants to be a pedant, one could say ‘reduce’ doesn’t mean ‘stop’, but if fewer individuals shed viable virus in the vaccinated than unvaccinated group, it has clearly STOPped transmission in a greater number of individuals in that group. It’s not that it’s generated the same number of transmitting individuals but with lower levels per individual; there are fewer transmitting individuals. That matters. Those individuals are invisible to the virus. It has the same effect as reducing population density.
Much of what can be said about vaccine can also be said about ‘natural immunity’. Yet one never hears a parallel uncertainty over transmission from previously infected individuals. Well, as it happens, data shows that this too is reduced (or ‘stopped in more individuals’) for reinfection of the original strain. There’s the rub. There are worrying signs that the Brazil mutant can reinfect individuals. If reinfection is occurring, the Brazil mutant is not a ‘vaccine escape mutant’; it is a ‘natural immunity escape’. So the thing he’s worried about actually results from the strategy he advocates.
The key to reducing mutations is to reduce replications. You can create a selective pressure by doing that, but you also reduce the opportunity for mutations that can respond to it. The optimum would be to vaccinate (or infect) everyone in a day! That would knock it on the head for sure (at huge cost of life and health in the second case). Failing that, mass vaccination should proceed as fast as possible. It gives the opportunity of creating hundreds of thousands of ‘pseudo-infections’ per day without the health costs and, crucially, without the replications. It would be neither possible nor desirable to hit the same numbers ‘the natural way’. ‘Letting the disease rip’ creates a substantial excess of replications over vaccination, hence more opportunities for mutation and selection.
This is not really the way to do science: by non-peer-reviewed ‘open letter’, uncritically leapt upon by the vaccine-skeptic community with neither the knowledge base nor the appropriate scientific skepticism needed to evaluate his claims. I’m no expert, but I think his strategy would be disastrous.