Blood supply and demand

Abstract

30 years on from a 1975 World Health Assembly (WHA) resolution urging countries to adopt nationally coordinated, voluntary, blood-transfusion services, fewer than 30% of member states have country-wide systems in place and many still pay donors for their blood—a practice known to jeopardise blood safety. Most developing countries do not screen donated blood for even the most common blood-borne infections. According to WHO, omitting such tests causes up to 16 million HBV infections, 5 million HCV infections, and 160 000 cases of HIV worldwide every year. A safe, plentiful supply of blood for transfusion is an essential component of any health system. But too many countries continue to use unsafe blood for transfusions and thousands of individuals die every year because supplies are short. In wealthy countries, demand is high and getting higher: one patient in every ten admitted to hospital needs some sort of blood product. Increasingly complex medical procedures and longer life expectancies are pushing up demand still further. For developing countries, the demand profile is different, but these nations are no less dependent on safe supplies. Women and children are the most in need. 70% of blood transfusions in Africa are given to children with malaria; the other major use for donated blood is to help treat women with post-partum haemorrhage. The 100 000 annual deaths attributed to this complication are evidence of the scale of the unmet need. Poverty is often cited as the main reason why poor countries find it hard to adopt safe transfusion practices. WHO asserts that for a blood donation system to be safe and effective it must be 100% voluntary. However, in all but 40 countries blood shortages are commonly dealt with by offering financial incentives for donation. The prospect of payment encourages potential donors to withhold medical information that might show them to be unsuitable; this leads, potentially, to unsafe blood entering the supply chain. To save lives, this practice must stop. Malawi is one of the few countries to show that switching to incentive-free donations is possible. It has managed to set up a functioning blood service based on voluntary donations in just 2 years. In this time, the death rate among children with malarial anaemia plummeted by 60%, and pregnancy-related maternal mortality fell by more than 50%. Even with incentive-free donations, however, effective blood-screening systems are essential to prevent disease transmission. South Africa and Zimbabwe have been successful in this respect: both countries maintain levels of HIV contamination of donor blood of below 0·5%, despite population rates of HIV infection that exceed 20%. Other countries have fared less well. WHO estimates that HIV-contaminated blood still accounts for around 5% of HIV infections in Africa, a figure that underlines the need for more stringent testing of donor blood. The emergence of HIV two decades ago also brought the issue of blood safety home to rich countries, where, despite the presence of well-organised, voluntary, blood-donation systems, thousands of people have been infected with HIV via transfusions. The US Centers for Disease Control and Prevention estimates that, as of 2000, 7807 HIV infections had been caused by contaminated blood in the USA. Since 1985, when antibody tests for HIV in donor blood were implemented, there have been far fewer cases of transfusion-associated infections. But the fact that slip-ups still happen has pushed the USA in particular to continue to strive for safer blood transfusions. In practice, this goal means adopting increasingly sophisticated methods of detecting infections. The USA is the only country to test for HIV RNA (the UK and other countries test for HCV RNA but not HIV RNA) and the method has reduced the risk of HIV or HCV transmission to one in 2 million blood units. But this achievement has incurred substantial costs. A recent estimate put the amount required to prevent one transfusion-associated HIV infection at US$2 million. Might this money be better spent on other forms of prevention? Appropriate safety measures are necessarily dependent on country, cost, and setting, but shortage of supply is the feature common to all blood-donation systems. World Blood Donor Day (June 14), inaugurated last year and given the official stamp of the WHA this May, should help to raise awareness of the need for more regular donors. But doctors, too, have a part to play in using blood more responsibly. Many blood transfusions are done unnecessarily and studies have shown that guidelines on appropriate blood usage are rarely followed. Blood is a precious commodity; we all have a duty to treat it as such.