The national lockdown that starts from Friday may buy SA some time. The unprecedented worldwide search for effective treatments could bear fruit, and our public health authorities have an opportunity to start systematic testing for the coronavirus.

Given the limited capacity of the country’s public health system, however, there are difficult and unavoidable decisions ahead about how scarce resources should be allocated. Governments always have limited resources, whereas health-care demands are essentially limitless. This poses the question: which patients first?

Frederick Banting and Charles Best discovered in 1922 that insulin could be used to treat diabetes. But only small quantities could be made. Banting simply decided himself who would be saved; this included his friends and powerful politicians.

In the early 1940s, the efficacy of penicillin as a treatment for a wide range of bacterial infections became clear. Since this was wartime, military uses were prioritised. Penicillin was “rationally” allocated according to its efficacy and the speed with which it would enable soldiers to return to the front. This meant gonorrhoea among soldiers was given priority over the lives of sick children.

Dialysis became feasible for chronic kidney disease in the early 1960s. Seattle’s Artificial Kidney Centre decided that “rational” choices should be made about which patients would have access to this lifelong and expensive treatment. A patient selection committee decided that beneficiaries had to be taxpayers in the state of Washington. Patients were also ranked by “social worth”: occupation, income, education, emotional stability and “future potential”.

A less explicit rationing unfolded two decades ago in SA with respect to antiretroviral (ARV) medication. Specialists argued about the merits of treating early phase HIV patients, who had better survival prospects rates, or later phase patients whose condition was more “urgent”. There was also debate about whether to prioritise children or specific occupational groups.

In reality, campaigners partly ducked the issue by arguing for a “universal programme” that could not be provided. Politicians were wary about becoming embroiled in debates about who should be treated, and hid themselves behind the obfuscation and confusion of the “denialist” era.

In practice, the question “which patients first?” was answered arbitrarily and unjustly. Resources were concentrated in private sector clinics and hospitals. Large companies extended coverage to their skilled workers to prevent reduced productivity and skills shortages.

Politicians, judges and senior public servants joined the rich at the front of the queue. Special programmes were designed for soldiers and police officers to maintain public order and the stability of the state. Health-care workers themselves received privileged access because they were at risk of infection and had to be well if they were to treat others.

Donor agencies elaborated their own criteria for deserving recipients. “Adherence to treatment” assessments saw patients selected on the basis of their family background, clinic attendance, emotional stability and commitment to safe sex.

Who was at the end of the queue? Rural programmes were almost nonexistent. The very poor everywhere were unable to pay the bribes that were sometimes needed. Outsiders or refugees found access hard or impossible.

Those stigmatised or confused about HIV/Aids simply did not come forward for testing or treatment. And those denied the education and information they needed to make informed choices about their own health died in ignorance of potential treatments.

Patient selection will be a potentially divisive issue once again over the coming months. Perceptions of unfairness could easily aggravate tensions based on race, class, religious belief or country of origin. In the short time we have been bought, we need a broader public debate, both about how very few patients our health system will be able to treat, and about the criteria by which they will be selected.

• Butler teaches public policy at the University of Cape Town.