Leviticus calls blood “the life of all flesh,” and observant Jews remove excess blood when cooking meat, while modern-day Jehovah’s Witnesses maintain a religious objection to blood transfusion.

They view it as a repugnant transaction: church members who voluntarily accept transfusions, even to save their lives, face exclusion from the religious community.

In the 17th century William Harvey established that blood circulates in the body, leaving the heart via arteries and returning via veins. But attempts to treat patients suffering from blood loss via transfusions were dangerous and sometimes fatal. It wasn’t until the early 20th century that Karl Landsteiner in Vienna identified blood types, whose compatibility between donor and recipient is important for successful transfusions.

Blood transfusions became standard in battlefield surgery during World War I, and Landsteiner won the 1930 Nobel Prize in Physiology or Medicine for his pioneering work. Standard medical practice had thus shifted from bloodletting (a technique used by physicians for centuries) to blood transfusion, but this transition was itself long and controversial.

Among the organizational advances that allowed blood transfusion to become a standard procedure was the development of blood banks, so supplies would be on hand when needed. Carl Walter founded one of the earliest in Boston in the 1930s. His obituary notes that Harvard relegated his blood bank to a basement because some officials in the 1930s thought blood banks and blood transfusion were “immoral and unethical.”

A great deal of further progress in using blood donation to save lives followed the discovery that blood plasma, the liquid part of the blood (without the blood cells), contains many lifesaving pharmaceutical products that can’t (yet) be manufactured but must come from human blood. These include immunoglobulins and clotting factors, needed throughout their lives by people with immune deficiencies and with hemophilia, as well as blood proteins administered in emergencies to patients suffering from trauma or critical illnesses, or during surgery. Plasma can be frozen and stored much longer than whole blood and can be obtained from a donation of whole blood. But plasma can also be donated independently of whole blood as “source plasma,” in a process during which the red blood cells are separated from the blood and returned to the donor. (The fact that red blood cells are returned to the donor means that donors can safely supply plasma more often than they can donate whole blood.) Plasma can be transfused directly into a patient, but it can also be fractionated into component parts, used to treat specific conditions.

The availability of blood and plasma has made many formerly untreatable diseases and conditions readily treatable. Blood, plasma and several components of blood plasma are on the World Health Organization’s (WHO’s) list of “core” essential medicines, which are “minimum medicine needs for a basic health-care system.”

But while blood, plasma and the pharmaceuticals derived from them are today quite standard for saving lives throughout the world, considerable repugnance is attached to paying blood and plasma donors for their services.

Part of the repugnance arises from the fact that blood transfusion opened a new avenue for the transmission of blood-borne diseases from infected donors. In the early 1970s, when there were no effective tests for pathogens in blood, blood banks relied on donors to refrain from giving blood when they felt ill. The concern with paying donors was that the cash might tempt them to donate blood even when they might be ill, which would lead to contamination of the blood supply and risk infection of patients who received transfusions. A related concern also involved risks to donors, who might become infected if unsterilized needles were used, and who may suffer health risks if they donate too frequently, before their bodies can regenerate the blood or plasma they have donated. The concern in this regard was that paying donors might motivate them to donate more often than was good for them, especially if blood banks failed to keep proper records.

Richard Titmuss, a professor of social policy at the London School of Economics, wrote an influential book in 1970, The Gift Relationship: From Human Blood to Social Policy, comparing blood obtained from unpaid donors in Britain (where no payment is permitted) to that obtained from both paid and unpaid donors in the U.S. He compiled convincing evidence, mostly from American studies, that blood from paid donors in the U.S. was more frequently infected with hepatitis than was blood obtained from unpaid donors in the U.S. and in Britain.

He also found payment for blood repulsive and concluded, based as much on this sentiment as on convincing evidence, that voluntary blood donation allowed more blood to be collected, more cheaply and efficiently, with fewer social or medical problems, and that it would be less subject to shortages of supply than paid donation.

Some of his passion, and his repugnance for payments, is evident from the long list of harms he attributed to payments to donors, including that the commercialization of blood and donor relationships represses the expression of altruism, erodes the sense of community, lowers scientific standards, limits both personal and professional freedoms, sanctions the making of profits in hospitals and clinical laboratories, legalizes hostility between doctor and patient, and subjects critical areas of medicine to laws of the marketplace.

Titmuss’s book received serious attention in the U.S. and elsewhere, where there was already concern about hepatitis in the blood supply. In a 1971 review, the economist Paul Samuelson (who won the Nobel in economic science in 1970) wrote approvingly that “in terms of quality (red cells, hepatitis risk), the blood you get for a buck is simply not as good as that you get for love.” Also in 1971, the economist Robert Solow (who went on to win a Nobel in 1987) wrote that “it appears to be – and probably is – a devastating and unanswerable indictment of the American system as inferior to the British in efficiency, morality and attractiveness.”

Among his conclusions quoted above, one that attracted discussion related to repugnance is that commercial donation limits personal freedoms. Titmuss’s final chapter, called “The Right to Give,” elaborates on this point, arguing that allowing paid donation would infringe on the right of willing donors to give blood altruistically, and prevent them from doing so. This is a different argument than is sometimes made, that paying donors might improperly coerce the poor to become reluctant donors because of urgent need of money.

In a 1972 review of Titmuss’s book, Kenneth Arrow (who the next year would win the Nobel in economic science) cited this as one of the more puzzling of Titmuss’s assertions. Arrow wondered why Titmuss thought that adding the option to be paid would coerce people not to make unpaid donations, as long as that option was still available. The following year, the philosopher Peter Singer replied that perhaps what Titmuss had in mind was that the presence of paid donation would cause the social appreciation of unpaid donations to wither away.

The intervening years have cast a great deal of new light on this discussion, as technology, health policy and infectious diseases themselves all evolved, and the medical uses of plasma products have increased. One can only imagine how surprised Titmuss (who died in 1973) would have been that, beginning in 1998, plasma donation was suspended in Britain for a quarter of a century because of fear of infection from unpaid British donors, with needed supplies imported from paid foreign donors, overwhelmingly from the United States.

But in the early 1970s, risks to patients and donors were still a very live concern, when commercial companies started exporting blood from countries including Haiti and Nicaragua, sourced from paid donors. In response, in 1975, the International Conference of the Red Cross and the WHO began to urge countries “to promote the development of national blood services based on voluntary non-remunerated donation of blood.” This is a position they have maintained to the present day, with considerable success around the world in discouraging payments to donors.

Nevertheless, as the first tests for hepatitis in the blood supply became available in 1971, paid donation of blood and plasma remained legal in the U.S. But the Food and Drug Administration requires that whole blood to be used for transfusion be labeled as coming from either a “paid donor” or a “volunteer donor.” Subsequently, almost all of the whole blood collected in the U.S. for transfusion has come from unpaid volunteers. This has mostly worked well enough to meet the demand for whole blood, with occasional local or seasonal shortages.

However, in 2022, the American Red Cross declared that the United States was experiencing a persistent nationwide blood shortage (possibly related to the Covid-19 pandemic, which began in 2020). Even prior to that, the biennial government report on blood donation reported that “blood donations decreased between 2017 and 2019. Donations from younger donors continued to decline while donations among older donors have steadily increased.” So it is possible that shortages of whole blood may become more frequent, if current conditions persist.

The 2022 shortage caused the Red Cross, which only accepts voluntary blood donations, to revise one of its more stringent rules about what constitutes a “voluntary” donation and what does not. There is a genetic disease called hemochromatosis, which causes iron to accumulate in the liver. The condition is treated by frequently drawing blood from these patients, since the red blood cells are rich in iron, and so drawing blood causes their bodies to put iron into regenerating red blood cells rather than concentrating it in the liver.

Prior to 2022, the Red Cross didn’t allow these patients to donate blood because it decided they weren’t voluntary donors since they were receiving a benefit from having their blood drawn. So the blood regularly drawn from these patients was simply discarded. However, starting in August 2022 the Red Cross relaxed this policy and allowed patients with hereditary hemochromatosis to donate blood rather than discard it.

But the FDA requires “paid” or “volunteer” labels only for whole blood, not for products obtained from blood, such as blood plasma, or other components that can be isolated from blood or plasma. So plasma collection in the U.S. is from both unpaid donors at not-for-profit community blood centers and paid donors at for-profit plasma collection centers, often owned by or affiliated with foreign biomedical companies. These U.S. collections supply domestic hospitals and pharmaceutical companies, as well as foreign ones through an active commercial market. Today, the U.S. exports billions of dollars’ worth of plasma and tens of billions of dollars’ worth of plasma products annually.

Note that new diseases are a constant threat to all sources of blood, from paid or unpaid donors. This became clear around the world after the first diagnosis of AIDS in 1981, but before the first tests for HIV became available in 1985. During that period, patients in need of blood and plasma suddenly found themselves at risk of infection, not just in poor countries but also in wealthy ones including the U.S., France, Britain and Canada.

In the U.S., the first sign that this new and still mysterious disease was being transmitted through the blood supply came almost immediately in a 1982 report from the Centers for Disease Control that hemophiliacs, who receive regular treatment with donor-derived clotting factor (extracted from the plasma of multiple donors, and so especially subject to contamination by an infected donor), were becoming infected. Almost 5,000 U.S. hemophiliacs became infected with HIV before 1985, and most of them died of AIDS-related infections as a result – although after considerable delay, which initially made the connection to the blood supply harder to see.

Immediately after HIV was identified, and before tests became available, blood banks adopted policies intended to screen out risky donors by asking questions about behavior. These focused on members of groups in which initial HIV infections had been found – namely, homosexual men, intravenous drug users and Haitian immigrants, and on exposure to the disease through sexual contact. I recall being asked before being allowed to donate blood whether I had male sexual partners, and if I had ever had sex in exchange for money or drugs.

What largely solved the danger of HIV in the blood supply, in addition to behavioral screening, was a combination of tests for the presence of HIV in blood and plasma, plus heating and solvent-detergent technologies that destroyed even undetected contamination by a broad class of viruses (much as handwashing contributes to dissolving lipids and destroying viruses). A retrospective look at that period finds that in the U.S. “there were essentially no new cases of HIV-1 after 1985” from contaminated plasma.

Since 1985 U.S. blood and plasma supplies have remained relatively safe, regardless of the payment status of donors, even as new disease threats have emerged (e.g., West Nile Virus). Tests for pathogens, treatments of the blood supply to deactivate them and behavioral questions continue to be updated, and all blood centers are subject to regular inspection by the FDA.

In France, a long-running criminal prosecution targeted individuals, including Laurent Fabius, the prime minister in 1985, on charges related to the contamination of the blood supply. They allegedly delayed the testing of French blood supplies after an American pharmaceutical company developed the first HIV test in 1985 in the hope that a test by a French company would become available. The last parts of this case were not finally resolved until 2003, when one of France’s highest courts (la Cour de Cassation) upheld a ruling that 30 government physicians, health officials and aides were not legally responsible for the delays in testing or the illnesses and deaths that resulted. Compensation for those illnesses and deaths had already been adjudicated in France by the time the criminal charges were dismissed.

Canada also experienced difficulty coping with its contaminated blood supply in the 1980s. Canada was a little slower than the U.S. in instituting tests for AIDS, and much slower in introducing tests for hepatitis, with the result that throughout the 1980s the blood supply remained dangerous.

In 1993 Canadian Justice Horace Krever was commissioned to study the events surrounding contamination of the blood supply: the report of the Commission of Inquiry on the Blood System in Canada was published in 1997. Part II of the Krever report concerns bureaucratic battles following the 1975 WHO policy that called for nations to be self-sufficient in unremunerated blood and plasma. (That’s a policy probably formulated to prevent rich countries from sucking resources out of poor countries, but as we’ll see, it now often prevents poor countries, or small ones, from accessing medical resources available in richer or more populous countries.)

In any event, political demands to achieve self-sufficiency were insufficient to achieve it, even in a rich country like Canada. The Canadian Red Cross Society, which played a big role in the Canadian blood system at the time, found itself buying plasma pharmaceuticals from the U.S. market. But the troubles of the 1980s undermined public confidence in the blood supply, and the Red Cross and the Canadian Blood Agency were relieved of their supervision of the blood system, replaced by Canadian Blood Services and (in Quebec) Héma-Québec. Those organizations continued to buy plasma from the U.S., but accepted only unpaid domestic donations, even though there weren’t yet legal bans on paid donations.

In 2012 the blood supply once again became a matter of public debate in Canada when a private firm applied for a license to open a paid plasma collection facility in Toronto, the capital of the province of Ontario. Another firm had been legally paying plasma donors in Manitoba. Nevertheless, this new application aroused immediate opposition, with calls for Ontario to pass a law banning paid donation of blood or plasma. (Quebec had passed such a law in 1994.) Opponents suggested that paid donation of plasma would reduce voluntary blood donation and introduce disease into Canada’s health system.

At the time, about 70 percent of the immu noglobulins used in Canada came from paid U.S. donors, and thousands of Canadian lives would be at risk if these were unavailable. A government report notes that there was no evidence from Manitoba that paid plasma donation reduced voluntary whole blood donation. It further notes that there was no evidence of crowding out of voluntary blood donation from countries that allow plasma donors to be paid, saying, “Germany, Austria and the U.S., which have well established paid plasma collection systems, are also among the world’s highest collectors of voluntary blood donations, with rates nearly double those of Canada.” And it notes that the new tests for pathogens, and safety procedures in processing plasma, have been successful: “As a result, there has not been a case of HIV or hepatitis transmission from plasma products in over 25 years.”

Nevertheless, in 2014 Ontario banned payment for blood donation, including blood plasma. Similar laws were passed in Alberta (which repealed it in 2020), and in British Columbia. These laws make specific exception for payments by Canadian Blood Services. In the wake of these laws, the health ministry noted in 2018 that the percentage of Canadian blood plasma imported from the U.S. had risen to 83 percent, and again noted that plasma and plasma-derived products from paid U.S. donors are safe: “There have been no confirmed cases of disease transmitted through PDPs [plasma-derived products] in over two decades.”

Around the time the British Columbia law was being debated, I had a conversation with an executive of the Plasma Protein Therapeutics Association, who had been talking to BC legislators. One legislator said to her that he could be convinced to vote against a ban on paying donors if he could be sure (and here I quote her from memory) that a donor “wouldn’t be some single mom on public assistance who was donating only so that she could buy Christmas presents for her kids.”

His concern seemed to be that paid donors wouldn’t be only college students needing beer money, but people with real monetary needs, and that it would be exploiting them to give them this particular opportunity to fulfill those needs.

Evidence from the U.S. suggests that people with real monetary needs are indeed a significant source of plasma donations, and that the payments they receive from plasma centers help them deal with temporary crises and household emergencies. For example, economists John Dooley and Emily Gallagher compiled a dataset of paid plasma centers in the U.S. and the dates at which they opened for business, and found that plasma centers reduced the demand for high-interest, short-term loans from nearby payday lenders. So the payments that plasma donors receive can improve their financial well-being not merely by providing additional income, but also by helping them avoid going into expensive debt.

I didn’t get to talk to the BC legislator in person, so maybe his concern wasn’t repugnance at letting poor people sell blood, but that if blood and plasma donation didn’t continue to be carefully regulated, poor people might be tempted to sell blood or plasma more often than it would be safe for them to do so. That’s a credible concern, and it’s why sales of plasma have to be carefully regulated and monitored. In the U.S., the CDC is one of the federal agencies responsible for ensuring the safety of the blood supply, while the Food and Drug Administration is responsible for ensuring the safety of blood donations and protecting donor health.

The 2020 repeal of Alberta’s ban on paid donation is a sign of growing awareness of Canada’s almost complete dependence on plasma from paid U.S. donors. But it wasn’t passed without controversy. Among the prominent opponents of repeal was the Canadian Federation of Nurses Unions. “Donating blood should not be viewed as a business venture,” said the president of United Nurses of Alberta.

Note that expressions of repugnance can be straightforward expressions of moral concerns and intuitions, but can also be a means of recruiting allies. It may have occurred to some members of the nurses’ union that the blood collection facilities run by the national Canadian Blood Services employ unionized nurses, while small commercial startups might not. However, this was not among the concerns included in their public statements about the repugnance of commercial blood collection.

The Canadian philosopher Peter Jaworski, a prominent campaigner against bans on compensating donors, summarized the state of the argument well:

Many people think blood is special in a way that means it shouldn’t be “commodified,” or bought and sold on a market. It is a basic human need. It’s not like the latest gadget or a pair of shoes; it is to be revered, not remunerated. I’m glad we don’t think food is special in this way. If we did, imagine how many more people would die of starvation, or would suffer from hunger.

So, the world of blood and blood money has changed a lot since 1970. And as Canada faced declines in voluntary plasma donation in 2022, Canadian Blood Services signed an agreement with the Spanish firm Grifols that will allow it to pay Canadian plasma donors with an aim to move domestic supply closer to 50 percent of domestic needs.

In Britain, where HIV and hepatitis also contaminated the blood supply in the 1970s and ’80s, a new issue arose in 1996 (long after the blood supply became safe from HIV), when patients who had eaten British beef infected with “mad cow disease” started to fall ill. They suffered from a variant of Creutzfeldt–Jakob disease (vCJD), a slow-developing but fatal neurological illness. The disease isn’t caused by a microorganism but by a protein, called a prion, that can fold in more than one way, and misfolded proteins can cause other proteins to misfold, which can cause gaps to develop in the brain. (Stanley Prusiner won the 1997 Nobel Prize in Physiology or Medicine for having earlier identified prions as the disease-causing agent in the rare but naturally occurring spontaneous version of CJD.)

There was no available test for prions in the blood, nor could prions be destroyed by heat or chemical treatment of blood and plasma. In addition, it takes a long time for people exposed to malformed prions to develop the disease. With the early 1980s experience of AIDS clearly in mind, medical authorities – all over the world, not just in Britain – were justifiably worried that people who had eaten infected beef might have donated blood or plasma while they were still in perfectly good health, yet contaminated the blood supply in ways that would stealthily spread vCJD to blood recipients to an extent that might only become apparent decades later. Indeed, medical authorities worried that an unknown but perhaps large number of people had already been infected through the blood supply, so that even vegetarians could further contaminate it by donating blood or plasma.

In the U.S., the FDA promptly banned donation by anyone who had lived for six months or more in Britain in the relevant years 1980-1996. This was a purely behavioral measure, asked of donors since no test was available. The ban slightly changed from year to year, and I was for a time included in the ban when the question became whether I had been anywhere outside of the U.S. for a cumulative total of more than six months during the relevant years. Many countries adopted similar bans.

British authorities made a much larger response in 1998, and suspended all domestic donation of source plasma, with plasma and plasma products instead imported, largely from the U.S. Plasma donation in Britain resumed only in 2021 after it had become clear that vCJD had not spread widely and didn’t spread easily through blood and plasma.

This is how almost exactly the opposite of Titmuss’s implicit 1970 prediction – that British-style unpaid donation would replace American-style paid donation – was realized. Britain did not ban whole blood donation, however, because there was no available commercial market from which overseas supplies could be safely obtained. (I surmise that they would have been ready to purchase blood commercially from a safe foreign source, if one had been available.) But they started to process blood differently, and removed white blood cells, which were thought to pose the greatest risk of infection with vCJD. And they instituted behavioral controls on who could donate, and in particular banned blood donation by people who had themselves received blood transfusions.

Overall, the British decisions to ban domestic plasma donation (but not whole blood donation) and to reinstate domestic plasma donation after a lapse of more than 20 years represent cautious attempts to balance risks. The risk of transmitting disease has to be weighed against the risks of not having sufficient supplies of blood and plasma, or of depending entirely on the commercial supply of plasma from the U.S. When the risk of transmitting vCJD in Britain arose in the 1990s, there was an increasingly long record of safe, commercially available plasma supplied by paid donors in the U.S.

But as international supply chains were strained by the Covid-19 pandemic in the early 2020s, and the risks of transmitting vCJD in Britain declined, adding back some capacity to obtain domestic source plasma in Britain helped to balance the risk of being entirely dependent on foreign supplies. At present, Britain still relies on paid U.S. donors for most of its supply of plasma and plasma products, but it is starting to build back some domestic capacity.

Another change since 1970 is that new evidence and new kinds of evidence have been gathered. Alongside the experience that has accumulated in a century of blood donation and blood banking, there has also been a growing attempt by economists and others to understand better the motivations behind uncompensated donation of all sorts. This work includes collaboration by an international group of economists from Argentina, Australia, Canada and the U.S. on donation of and compensation for blood, and also organs for transplant.

A paper summarizing some of this work appeared in the journal Science. Regarding compensation for blood donors, it concluded that, in light of all the evidence so far, “there should be little debate that the most relevant empirical evidence shows positive effects of offering economic rewards on donations.” That is, rewarding donation results in more donation.

The WHO, however, maintains its insistence that nations should be self-sufficient in plasma, despite the fact that its own data indicate that the voluntary non-remunerated blood donation system has been a tragic failure for precisely the resource-poor countries they seem to believe it protects.

WHO’s 2022 report says, “Despite progress over the past decade, it is clear that the goal of universal access to safe blood and blood products has not been achieved in many countries.” The report finds that countries in the low-income groups collected 2 percent of global donations of blood and blood plasma, despite being 8 percent of the global population. Lower-middle-income countries collected 24 percent of global donations, despite making up 40 percent of the global population.

These data are consistent with complaints about WHO policies from medical aid workers in sub-Saharan Africa. The problem is not just that blood shortages deprive patients in poor countries of medical treatments developed in richer countries in the last 50 years. Given the shortages of blood and plasma, and the conditions of poverty, the uses of blood and plasma in low-income countries resemble the battlefield conditions in which transfusions were first used. Blood and plasma in poor countries are not only in short supply; they are often needed in emergencies to treat injuries in accidents and conditions correlated with poverty, like hemorrhaging during childbirth. The situation shows little sign of improvement over time.

Yet the WHO (still) regards blood donation much as it does kidney donation, and still recommends that countries should be self-sufficient and not allow paid donation. It calls this a “requirement” in the same updated 2021 document that lists elements of blood and plasma as among the minimum needs of any health care system.

In many countries, people in need of blood (e.g., before a scheduled surgery) are asked to provide “family replacement” donations. But professional blood donors are available to pretend to be family members. Often, such as in India and Africa, the hospital can advise patients how to find such donors on the black market for blood.

No country in the world has achieved a sufficient supply of blood products without allowing at least plasma donors to be compensated. Although many wealthy countries are able to fill their domestic demand for whole blood from volunteers, countries – including wealthy countries – that don’t allow donors to be paid for plasma regularly recover far less plasma from volunteers than is needed for their domestic patients.

What prevents this from developing into a worldwide medical catastrophe is that a small group of wealthy countries recovers sufficient plasma by allowing their domestic donors to be paid, and these countries can supply the needs of most of the rest of the world. In particular, the U.S. supplies much of the world’s blood plasma, collected from paid donors. Germany, Austria, Hungary, the Czech Republic and Latvia are the European countries that allow plasma to be collected from paid donors, although my understanding is that some of them stipulate that the payments are made for the time involved, not for the plasma itself. China also allows plasma donors to be paid.

This means that many of these plasma-importing countries find themselves taking the confusing moral position that paying domestic plasma donors is immoral, but that it is acceptable to fill the resulting shortage by purchasing plasma from paid U.S. donors.

Perhaps it shouldn’t be surprising that people who object to paying donors don’t object if their national institutions simply buy the necessary supplies from overseas. Out of sight, out of mind is a traditional way of dealing with morally complex issues.

But while this has worked well enough so far for wealthy and middle-income countries, poor countries have much less ability to purchase what they need on the world market. The fact that paid donation raises more supply than relying entirely on altruistic donation suggests that perhaps these countries should be released from the contradictory demands to radically raise supplies without compensating donors. Poor countries receive substantial foreign aid aimed at helping them increase their supply from unpaid volunteers. Another way of relaxing this restriction would be to let countries use some of this aid to purchase plasma on the international commercial market, as rich countries do.

There is now abundant evidence of many sorts that rewarding donation results in more donation. Of course, introducing paid donation where it is absent would require careful experimentation, cautious implementation, and sustained monitoring and regulation. The threats of contamination of the blood supply that modern technology overcame in the wealthy world might be harder to overcome in low-income countries.

But the same kind of randomized control trials that have established the value of other health care policies in low-income countries could be employed to test and refine ways of allowing low-income countries to increase their safe blood supply by compensating local donors. Repugnance alone shouldn’t be allowed to continue to cause unnecessary suffering and premature death in low-income countries when the more practical concerns about blood supplied from paid donors have been successfully solved.

Health care that’s good enough for the rich shouldn’t be repugnant for the poor.