In 2010, the idea of "Proportionate Universalism" (PU) was suggested to help make health care fairer for everyone, but it's not commonly used yet and there are no clear ways to put it into action.
The review looked at 55 articles to see how PU is understood and used; it connects two ideas: universal care for all and targeted help for those who need it most.
While some researchers tried to apply PU, they faced many challenges like deciding who needs help and how to measure if their efforts are successful; more research is needed to improve these aspects.