What’s the serious problem the developing countries face?

On World Health Day the World Health Organization has released a report saying that (28) there is a serious problem in developing countries because there are not enough health workers, such as doctors and nurses. Many of these professionals are leaving their countries for better-paying jobs, but this is having a bad effect on the world’s health services.
    (29) Of the fifty-seven countries which lack health workers, thirty-six of them are in sub-Saharan Africa, the very same countries which are struggling to cope with the AIDS epidemic. The World Health Organization says the shortages are undermining not just the battle against deadly diseases like AIDS, tuberculosis and malaria; they’re affecting childhood vaccination campaigns and basic care for pregnant women.
    (30) The report calls for ethical recruitment policies for migrant health workers and international investment to help poor countries train more staff because at the moment the world is short of four-million health workers and one-point-three-billion people lack even the most basic health care.