One solution that is starting to attract the attention of public health experts is a so-called weighted lottery, which gives everyone a chance at access, although some get a better shot than others.

Doctors and ethicists rank patients, deciding which groups should be given preference and how much. First-responders, for example, may be weighted more heavily than, say, very sick patients who are unlikely to recover.

The goal is to prevent haphazard or inequitable distribution of a treatment or vaccine when there isn’t enough to go around. Such a system has already been used in allocations of remdesivir, the first drug shown to be effective against the coronavirus…

They also noted another advantage: Weighted lotteries can allow researchers to find out, in a rigorous way, which subgroups of patients do best with a new drug or vaccine.

That is because allocation within a group is random. The distribution is, in effect, a randomized, controlled clinical trial. The only difference between, say, people over age 60 who got the drug and those who did not is the toss of a coin in the lottery.