Welfare states around the world restrict access to public healthcare for some migrant groups. Formal restrictions on migrants' healthcare access are often justified with economic arguments; for example, as a means to prevent excess costs and safeguard scarce resources. However, existing studies on the economics of migrant health policies suggest that restrictive policies increase rather than decrease costs. This evidence has largely been ignored in migration debates. Amplifying the relationship between welfare state transformations and the production of inequalities, the Covid-19 pandemic may fuel exclusionary rhetoric and politics; or it may serve as an impetus to reconsider the costs that one group's exclusion from health can entail for all members of society. The public health community has a responsibility to promote evidence-informed health policies that are ethically and economically sound, and to counter anti-migrant and racial discrimination (whether overt or masked with economic reasoning). Toward this end, we propose a research agenda which includes 1) the generation of a comprehensive body of evidence on economic aspects of migrant health policies, 2) the clarification of the role of economic arguments in migration debates, 3) (self-)critical reflection on the ethics and politics of the production of economic evidence, 4) the introduction of evidence into migrant health policymaking processes, and 5) the endorsement of inter- and transdisciplinary approaches. With the Covid-19 pandemic and surrounding events rendering the suggested research agenda more topical than ever, we invite individuals and groups to join forces toward a (self-)critical examination of economic arguments in migration and health, and in public health generally.