OAS1 and COVID-19: While in their case the two-step method allowed them to increase the power of fine-mapping and suggest a common putative causal variant possibly responsible for both the OAS1 splicing pattern and COVID-19 severity, in reality we could also imagine a situation where too strong priors from one study result in inflation of PIP in another study (even in their case, uncertainty exists in that the putative causal variant is not the lead variant in the African dataset).