The USA and Cuba.
Lifespan approxiamately the same at 77 years. Cuba has one of the lowest child mortality rates in the world - even lower than the USA. Generally speaking they are as healthy or healthier than Americans.
The reason appears to be their health care system, which puts the emphasis on prevention rather than treatment. All mothers are checked throughout their pregnancies, all children receive all their vacinations and get regular visits and screenings.
The cost of health care in Cuba is 1/14th of the cost in the US!