the 1990s, the mortality rate for boys under the age of 5 declined by 2.3 percent a year on average, but the mortality rate for girls under the age of 5 rose by 0.5 percent a year. The World Bank report does not go into detail to explain these differential effects, but one fact identified by the report is that China was charging for immunizations in the 1990s. An explanation could be that the rising immunization costs have forced rural households to choose between boys and girls in allocating the shots.
