[janekm]

The reason a vaccine is months or years away is only because we are testing whether it is safe enough to give to billions of people. The reason we do that is because a virus can cause disease both directly but also in unexpected ways (e.g. by immune over-reaction to some of the viral RNA in some individuals). Variolation as a public policy would have to go through the same safety testing for the same reasons (as it is a form of vaccination with un-weakened virus). You would also still have to produce doses of the variolate, both in terms of replicating the virus and bottling it.

There is no real time advantage to variolation. Anybody making the case for variolation without validation would be better off making the case for vaccination with one or several of the 30 vaccine candidates under study for SARS-Cov-2 right now (a case could be made... allow volunteers to be given the candidate vaccine of their choice in larger numbers than normal clinical trials, scaling up as the risk profile of each candidate vaccine is known).

[frank2]

I am not an expert (but neither are you, I am guessing).

>Anybody making the case for variolation without validation would be better off making the case for vaccination with one or several of the 30 vaccine candidates under study for SARS-Cov-2 right now

The advantage variolation has over the 30 vaccine candidates, I am guessing if the question is what to do before the results of testing are available is that most of those 30 candidates will turn out after being tested to fail to confer significant immunity.

I believe that the fate of most vaccine candidates for any disease is that testing reveals that the candidate fails to confer immunity to most or all of the people it is given to. Also I believe that it usually takes at least a year to produce enough of a vaccine to test, then test, then analyze the results of the testing.

[vikramkr]

Variolation could fail as well. It would still need to be tested for safety and efficacy.

[Matticus_Rex]

Tested for safety? We know what it does. It gives a low dose of the virus. If we know most people will get it anyway, then we don't need to know more than that in terms of either safety or efficacy.

[vikramkr]

A low dose could trigger an incomplete immune response leading to antibody dependent enhancement (ADE) on exposure to the virus in the future. Other Coronavirus are known to have that characteristic, we dont know if this strain does. Safety is making sure that we aren't priming people to get worse versions of the disease like what unfortunately happened with dengue.

https://www.pnas.org/content/117/15/8218

https://en.m.wikipedia.org/wiki/Dengvaxia_controversy

[ggreer]

Low doses of SARS seem to have much lower mortality: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3367618/

Of the 79 infected, 19 died. E block (where the index patient was), had 53 infections and 15 deaths for a mortality rate of 28%. Other units had 26 infections and 4 deaths, for a mortality rate of 15%. The death rate of patients in E7 (closest to the index patient and with the highest viral load) was 70%. That's more than 4x difference in mortality based on viral load!

It would be very surprising if low doses of SARS-CoV-2 caused higher mortality. Therefore should allow researchers and volunteers to experiment with low dose deliberate infection. It could save hundreds of thousands of lives.