A global report showed that 119 out of 196 countries - mostly in Africa, Oceania and South Asia - do not have sufficient blood supplies to meet hospital requirements.

WHO recommends that countries have at least 10 donation units per 1,000 people. But in Africa, 38 countries are less than this target, the researchers estimate.

South Sudan was found to have the lowest amount of blood supply, including only 46 units per 100,000 people.

The researchers said the African nation's need for blood supplies was 75 times greater than the supplies available. They found that India had the largest deficit, with a shortage of 41 million units. They highlighted the need to invest in low- and middle-income countries to expand national blood transfusion services.

Developing countries rely on blood transfusions because of the high prevalence of blood-borne diseases and complications during pregnancy.

More than 100 million units of blood are donated annually to these countries, which make up 80% of the world's population.

High-income countries, with only 16% of the world's population, bear the brunt, providing 42% of blood to developing country banks.

In the study, researchers at the University of Washington analyzed the World Health Organization's World Health Report on blood safety and availability for every country in the world.

To estimate the total blood requirements in any country, the researchers calculated the number of blood units needed for 20 different medical conditions.

Taking into account their spread by region, the Panel estimates the gap between supply and demand in each of these countries. They then reviewed it with data from the Global Status Report on Blood Safety and the 2017 Global Burden of Disease Study.

The team estimated blood use rates using patient practice in the United States. Preliminary results provide a rough estimate for health managers, which can help them prepare for the future.

The findings, published in the Lancet magazine, revealed that each country needed more blood supplies than the WHO target.

As the population increases dramatically and access to hospital care increases, the demand will increase, the researchers say. Strategic investments are needed in many low- and middle-income countries to expand national blood transfusion services, blood management systems and blood transfusion alternatives.