Ask Brian Chituwo, Zambia's minister of health, about Aids and he rolls his eyes skyward. "Aids, Aids, Aids," he says. "It takes so much money. We would like more for prevention. There's no point giving a child drugs to treat HIV if they then drink infected water and die of cholera."
Zambia is one of the African nations hardest hit by the medical, social and economic burden of HIV/Aids. But in the battle for scarce resources to support daunting health demands of all sorts in poor countries, the minister's attitude sums up growing concern that a few high-profile diseases risk absorbing too much.
The debate is important because of the huge human and economic cost of illness and premature death in the developing world. It is of ever greater relevance because of the substantial and fast-growing sums being spent by donors.
Discussion is particularly intense this week. Two plans aimed at tackling the tensions were launched at the Clinton Global Initiative in New York while Kofi Annan, the former United Nations secretary general, has been concluding a round of appeals to world leaders to inject a fresh $10bn (£5bn, €7bn) into the Global Fund to Fight Aids, Tuberculosis and Malaria at its latest pledging meeting in Berlin.
Since its creation with Mr Annan's backing in 2001, the Global Fund has become the world's largest multilateral funder of health projects, amassing nearly $10bn so far and planning annual disbursements of $8bn by 2010.
But there are concerns that the sums pushed into so-called "vertical" health programmes, set up to tackle particular diseases, can have unintended negative consequences. In particular, they risk diverting attention from, or even undermining, broader "horizontal" health systems established to prevent and treat all forms of ill-health. Barbara Stocking, director of Oxfam, the development charity, says: "Ultimately what we want is really decent basic health systems. There's a danger that if we start delivering vertical programmes, basic services suffer."
Since the turn of the millennium, a handful of tightly focused international initiatives have pushed an increasing share of all aid from donors around the world into health - and into vertical programmes in particular. The trend seems set to continue. The latest estimates from UNAids, a specialist agency, this week forecast that spending from all sources on HIV/Aids alone would have to rise from $10bn this year to as much as $63bn by 2015 if political commitments of treatment for all who need it are to be met.
The Global Fund is not the only agency focused on a handful of high-profile diseases. In the US, President George W. Bush has created two ambitious aid programmes of this type: the $15bn, five-year Pepfar programme launched to tackle Aids in 2003 - and lobbying to receive the same support again in 2008 - and the $1.2bn President's Malaria Initiative created in 2005.
Elsewhere the UN-backed Global Alliance on Vaccines and Immunisation (Gavi), whose spending reached $1bn last year, concentrates on delivering a range of childhood vaccines from the developed world into poorer countries. The World Bank, which helps finance the development of health systems, has also for decades earmarked support for specific programmes, from the elimination of river blindness to current low-cost loan initiatives to tackle HIV and malaria.
Margaret Chan, director general of the World Health Organisation, has made strengthening health systems a top priority since her election last year. Yet - at its member countries' insistence - the agency has long devoted far greater resources to vertical programmes such as Stop TB, the Global Malaria Programme and Three by Five (3m HIV patients on treatment by 2005) and, more recently, pandemic flu.
It is easy to see why. WHO achieved a powerful success with the elimination of smallpox 30 years ago, luring it into what critics called "eradication-itis" with similar efforts to wipe out diseases including polio and leprosy.
More generally, officials, politicians and individual donors like the clear, tangible focus provided by vertical programmes and the measurable results they provide. They are more easily wooed by dramatic success stories of lives saved or diseases conquered than the less glamorous and more subtle tasks of primary and preventive care. "There is a Lazarus effect with treatment," says Jim Kim from Harvard Medical School and one of the architects of Three by Five. "It is immediately understandable to everyone. HIV in particular has the greatest advocates to keep the funding going."
But the mood is shifting. One concern is how far such programmes prove counter-productive by displacing resources from health threats that may be just as important or even more so. Roger England from Health Systems Workshop, an advisory group, argued in the British Medical Journal this year that HIV, which he dubbed "the biggest vertical programme in history", was receiving too much money. HIV consumes more than one-fifth of all health aid around the world, he pointed out, but accounts for just one-twentieth of the burden of disease in low- and middle-income countries and causes lower mortality than stillbirths, infant deaths or diabetes.
Sophisticated equipment, heavy demands on medical staff and costly medicines mean HIV consumes large amounts of money for each patient treated. Alan Fenwick, a professor at Imperial College in London, argues that far more modest resources could transform the lives of millions of sufferers of such debilitating but "neglected" conditions as the hookworm parasite, trachoma (a bacterium that causes blindness) and schistosomiasis (bilharzia).
A second worry is that HIV and other vertical programmes funded by individual donors - each with their own different criteria and conditions for evaluation - create wasteful administrative burdens and encourage a brain drain of medical experts away from already weak state health systems. A study published last year on Rwanda showed that $47m of international assistance for health - or three-quarters of the total - went to HIV, while just $18m was for malaria and $1m for integrated management of child illnesses - although both alternatives were judged more serious priorities by the authorities.
Furthermore, the government controlled just 14 per cent of this aid, with 55 per cent channelled at the insistence of its 21 donors through non-governmental organisations instead. These groups hired many of the country's best medical staff from the state health system, typically paying doctors six times as much.
Elaine Gallin from the Doris Duke Charitable Trust, who helped design a $100m African Health Initiative grant programme launched this week to strengthen fragile health systems, says: "There is so much money being poured into certain areas that it is skewing the delivery of primary healthcare. It's as if you were fixing only one piece of the car and forgetting to put the wheels on."
A final set of issues includes the risk that such large sums forced into HIV divert resources to groups with limited expertise not best suited to spend them most efficiently; and that potential savings in treating the disease alongside others are limited by rivalries among recipient organisations as well as a stigma that keeps Aids facilities separated from other parts of the health system.
Not everyone is convinced by such arguments. Michel Kazatchkine, this year appointed head of the Global Fund, asks: "Where is the damage caused by vertical support? People on anti-retroviral therapy don't see any damage." He and his colleagues argue that the Global Fund has generated substantial donations that would not have been made to support health more generally - providing the fuel without which the metaphorical car of African health would not run at all.
Keith Bezanson from the International Institute for Sustainable Development in Sussex says that the debate between horizontal and vertical support for health programmes is "hollow, ideologically driven and exaggerated".
"Some of the vertical programmes have been among the greatest successes in development in recent decades," he says. He cites pesticide spraying in Latin America and south Asia that all but eliminated malaria there in the 1960s and 1970s, vitamin A and iodine supplements to boost child health and a sharp rise in vaccinations since the 1980s. "They saved countless hundreds of thousands of lives."
Nevertheless, while few public health specialists argue that existing support for HIV and other high-profile diseases should be reduced, many now see the need for greater attention in the future on protecting and strengthening general health systems in the developing world.
Julian Lob-Levyt, the head of Gavi, has introduced bonus payments for each child vaccinated, which recipient countries can spend on any aspect of their health systems. He forecasts that such sums will amount to nearly one-third of his agency's annual expenditure. "We are realising that for sustainability, we need to build platforms to deliver in an integrated way," he says.
Jens Stoltenberg, the prime minister of Norway, which has been a substantial backer of Gavi, this week announced $1bn in grants designed to support the UN's millennium development goals to improve maternal health and reduce child mortality, which have suffered from a focus on another goal: tackling HIV and malaria. Like the Duke project, the grants programme was launched at the annual meeting of former US President Bill Clinton's Global Initiative.
"Still close to 10m children die each year from diseases that they could easily be saved from," says Mr Stoltenberg. "We are now going beyond vaccination to target infant mortality and maternal health. We need basic infrastructure to deliver malaria bed-nets, advice on breast-feeding and skilled birth attendants that could save millions of lives."
At the launch in the UK this month of the International Health Partnership, designed to co-ordinate donors' efforts in the field, Mr Kazatchkine said the Global Fund would also be discussing fresh efforts to support health systems at its next board meeting in November. Anders Nordstrom, the senior WHO official in charge of health systems strengthening, is encouraging greater reflection by donors, recipients and intermediary agencies on how best to limit any negative impact from vertical programmes. "We are talking more and more about a 'diagonal' approach that tackles the constraints to achieving horizontal, system-wide effects," he says.
But that leaves an important concern. Harvard's Dr Kim, who defends a focus on HIV, queries how funds would in reality be allocated if they were intended to support a country's healthcare functioning in general: "My question to people arguing for broad-based health systems funding is, 'what would you do with the money next week?'"
Chris Murray, professor of global health at the University of Washington, Seattle, argues that there have been few studies showing which models work best and who is best equipped to distribute and spend the money. "The underlying premise is that we know what to do to best deliver primary healthcare. We need [instead] to foster innovation and evaluation."
Placing funds into already inefficient health systems may otherwise prove still less productive than money spent on vertical programmes.
