It languished because human trials are expensive and vaccines against rare diseases don't make any money. Correct. This is because regulations raise the barrie

It languished because human trials are expensive and vaccines against rare diseases don't make any money. Correct. This is because regulations raise the barrier to entry for new drugs to $2.6 billion (in 2019 dollars) https://www.policymed.com/2014/12/a-tough-road-cost-to-develop-one-new-drug-is-26-billion-approval-rate-for-drugs-entering-clinical-de.html https://www.policymed.com/2014/12/a-tough-road-cost-to-devel... Obviously, some amount of testing is necessary to bring a new drug to market (and the examples you point out support this). If there is no alternative but suffering and death for a condition, having these blanket regulations in place that block new drugs and new treatments only contributes to suffering.