Child mortality worldwide has fallen 41 percent since 1990, the result of myriad improvements in nutrition, access to vaccines and antibiotics, cleaner deliveries, better care of infants immediately after birth and the use of insecticide-treated mosquito nets.

That’s the finding of a report released Wednesday by three United Nations agencies and the World Bank.

Last year, about 6.9 million children under age 5 died, down from 12 million in 1990. Globally, there are now about 58 million deaths a year in people of all ages.

“The story is one of significant progress and unfinished business as well,” said Geeta Rao Gupta, deputy executive director of UNICEF. “On average, around 19,000 children still die every day from largely preventable causes.”

The country-to-country variation in child mortality rates is huge, and growing wider despite the progress. Among the world’s roughly 200 nations, only Somalia showed no decrease in the under-5 mortality rate over the past two decades.

The lowest rate in 2011 was in Singapore, which had 2.6 deaths of children under age 5 per 1,000 live births. The highest was in Sierra Leone, which had 185 child deaths per 1,000 births. The global rate is 51 deaths per 1,000 births. For the United States, the rate is eight per 1,000 births.

About half of all child deaths occur in just five countries: India, Nigeria, the Democratic Republic of the Congo, Pakistan and China.

Almost two-thirds of all child deaths are caused by infectious diseases. Pneumonia, diarrhea, malaria and measles are the biggest killers. About 40 percent of deaths occur in the first month of life. Those “neonatal” deaths are becoming a larger fraction of childhood deaths because they are harder to prevent with cheap and low-tech interventions than deaths in older children.

Increased access to clean water and the decline in defecation in the open has helped decrease deaths by diarrhea, as has use of oral rehydration salts and zinc supplements. There’s been a big push to make antibiotics easily available to children with pneumonia, which is responsible for 18 percent of childhood deaths. The proportion of African children sleeping under mosquito-
repelling nets — a practice that cuts malaria cases by more than half — rose from 2 percent in 2000 to 38 percent in 2010.

Introduction of the Hib, pneumococcal and rotavirus vaccines have also saved millions of lives, the report noted.

“Previously it took a new vaccine about 20 years from its introduction in Europe and America to when it reached Africa and Asia,” Mickey Chopra, UNICEF’s chief of health, said in a telephone conference with reporters. “With the new vaccines for pneumonia and diarrhea it’s taking us less than two to five years.”

Globally, childhood mortality has been declining more rapidly in the last decade than it did two decades ago. The decline was 3.2 percent a year from 2000 to 2011, compared with a 1.8 percent annual decline in the period from 1990 to 2000.

In poor regions of Africa and Asia, the increased survival of children comes from social progress as well as medical and environmental improvements. The improvement in women’s status especially benefits children, many studies show.

“There’s been some analysis showing that the countries that have made the biggest progress are ones who have invested in getting girls into school,” Chopra said. “There’s quite a strong correlation between the education of a mother and the survival of her child.”

The report was produced by a U.N. interagency group that included UNICEF, the World Health Organization and the U.N. Population Division, along with the World Bank.