The first time I came across the name Rudolf Virchow was when I was a medical student. My pathology textbook honoured Virchow as the founder of cellular pathology, which is the theory that all diseases can be understood from the functioning and malfunctioning of cells. This revolutionary idea replaced humoral pathology, the theory that diseases originate from a disbalance between four bodily juices. Although molecular pathology is now gradually replacing cellular pathology, many of Virchow’s basic ideas still hold true, such as the notion that disease is an expression of normal life processes under abnormal circumstances.1

The second time I came across his name was when I entered public health. Similar to John Snow, who is a hero both of anaesthetics and of public health, Rudolf Virchow is a hero both of pathology and of public health. He is one of the founding fathers of social medicine, the continental European precursor of modern public health.2 His statement “Medicine is a social science, and politics nothing but medicine at a larger scale” is one of the most frequently quoted one-liners in public health, even in the English-speaking world. It summarises public health’s biggest idea: human health and disease are the embodiment of the successes and failures of society as a whole, and the only way to improve health and reduce disease is by changing society by, therefore, political action.

The purpose of this article is to retrace the origins of this idea, which has recently become even more popular than it already was, as can be seen in the international movement towards “health in all policies”.3

RUDOLF VIRCHOW AND THE REVOLUTION OF 1848

Rudolf Virchow, who was born in 1821, wrote extensive memoirs that were published on the occasion of his 80th birthday in 1901.4 In his “Zur Erinnerung” Virchow describes the extraordinarily wide spectrum of his activities which not only extended from pathology to public health but also encompassed anthropology and prehistory. The key event which, in his own view, inspired him to all these activities was a trip that he made to Upper Silesia in early 1848 to conduct an official investigation into the causes of a typhus epidemic.5

In this report, he established the medical diagnosis of the disease (spotted fever, now known to be caused by Rickettsia transmitted by the human body louse). He knew this type of typhus to be associated with hunger and war, and identified the deeper causes of the epidemic as social and ultimately political. The direct cause of the epidemic was the famine of the previous years, which in its turn was due to crop failures because of bad weather. But the effects of the famine were concentrated among the poor, who were predominantly Polish peasants. In Virchow’s analysis their poverty, which was closely associated with their lack of schooling, originated from political oppression by the reigning bureaucracy, and from economic oppression by the local aristocracy. Therefore, Virchow argued, elimination of social inequality was the only way to prevent typhus epidemics in the future.5 6

Only 8 days after Virchow’s return a revolt broke out in Berlin, as it had done or would soon do in many other European capitals. On the night of 19 March 1848, Virchow himself defended a barricade using an old pistol he had borrowed from a medical colleague. During the rest of the same year Virchow remained politically very active, and participated in a variety of democratic, republican and socialist movements, including a medical reform movement. Virchow created a weekly journal called Die Medicinische Reform, which appeared between July 1848 and June 1849.6^–8

It is in this journal that he published many of his famous one-liners. “If medicine is the science of man both healthy and ill, which after all it should be, what other science could then be more appropriate to deal with law-making, in order to apply the laws that are given in mankind’s nature to the foundations of the organization of society?”9 In these opinions he closely followed his 2 years older colleague Salomon Neumann, who had declared that “medical science is in its innermost core and essence a social science”.10 This idea had been developed in the 1830s by French doctors, and led Jules Guérin to coin the term médecine sociale in two papers in the Gazette Médicale de Paris published on 11 and 18 March 1848. Not to be confused with médecine socialiste, médecine sociale refers to the totality of the relations between medicine and society.11

In a piece on Poor Law Doctors published in Die Medicinische Reform in July 1848, Virchow wrote that doctors are “the natural attorneys of the poor”. In another piece on the same topic, published in November 1848, he writes “Medicine is a social science, and politics nothing but medicine at a larger scale”.9 Statesmen had always liked to see themselves as doctors at the sickbed of society. The British reformer Jeremy Bentham (1748–1832) wrote that “the art of legislation is but the art of healing practised upon a large scale. … The physician relieves [the miseries of life] one by one; the legislator by millions at a time.”12 Virchow turns this metaphor upside down: he sees medical doctors as the better statesmen.

Virchow’s political stand led to his discharge from the Charité Hospital in March 1849, but after some years spent in exile in Würzburg, where he developed his ideas about cellular pathology, he returned to Berlin to take up a position as Professor of Pathology at the Charité in 1856. In 1859 he was elected a member of the Berlin Community Council, which he remained until his death in 1902. While continuing his scientific work as a pathologist, and later as an anthropologist and prehistorian, the politician Virchow fought for safe drinking water supplies and sewage removal, for hygiene in slaughter houses and for new hospitals, for children’s vaccinations and for gymnastics lessons for girls.6^–8

Interestingly, there was a close connection between Virchow’s work in cellular pathology and his ideas about public health. In his pathological work he often used political metaphors, for example when he described the living organism as a “free state of individuals with equal rights, although not with equal talents, which is kept together by the fact that the individuals depend on each other”. In his Cellularpathologie, which appeared in 1858, he writes “The cell can claim to be the real citizen, the legitimate representative of the singularity of existence, just like we claim to be this in human society, in the state … .”13

Similarly, society and the state are described in terms of biological metaphors. For Virchow, the state was a living organism consisting of individual beings who cooperate for mutual benefit. Just as he emphasised the autonomy of the cell within biological organisms, he also emphasised the autonomy of individual human beings as members of society, who should have equal rights and not be subordinated. For Virchow, the human body is the “ideal state of liberalism”, and the example of cells in the body provides the model for a “classless society of civilians”.6

Just like disease is nothing but life processes occurring under unfavourable circumstances, so epidemics are collective illnesses which are “indications of large disturbances of collective life”. “Each time when many people find themselves in similar, disadvantageous circumstances, many will fall ill, and diseases will be endemic or epidemic”. “Epidemics resemble big warning signs, on which the statesman of great stature can read that the development of the population has met a disturbance which even carefree politics can no longer overlook.”6

GEOFFREY ROSE AND THE EMERGENCE OF “POPULATION HEALTH”

Although one will still find medical doctors in national parliaments and municipal councils, even in positions as presidents and prime ministers, no one will seriously contend that medical doctors are better statesmen than men and women from other scientific disciplines. We no longer consider analogies between biology and sociology to be a reliable basis for political decisions. This part of Virchow’s big idea is certainly out of date.

That does not apply to the other parts, however. Geoffrey Rose (1926–1993) is the modern champion of the idea that whole populations can be sick, and that political action may be needed to improve population health. In the very first paragraph of his book The Strategy of Preventive Medicine he already discloses his Virchovian inspiration, when he cites Rudolf Virchow as saying that “epidemics appear, and often disappear without traces, when a new culture period has started. … The history of epidemics is therefore the history of disturbances of human culture.”14

Rose developed the idea that the causes of incidence (population-level illness) are different from the causes of cases (individual-level illness). He takes the example of the systolic blood pressure distributions of Kenyan nomads and London civil servants—which hardly overlap—to argue that conventional epidemiological studies may lead to “a complete understanding of why individuals vary” but fall short on “the most important public health question, namely, ‘Why is hypertension absent in the Kenyans and common in London?’.” “The clues [to the causes of incidence] must be sought from differences between populations or from changes within populations over time.”15

The idea that healthiness is a characteristic of a population as a whole, and not only of its individual members, can already be found with the French sociologist Émile Durkheim (1858–1917), who wrote that “each society is seen to have its own suicide rate”. While suicide seems to be a highly individual decision, national suicide figures vary by a small number only from year to year, expressing “the tendency to suicide with which each society is collectively afflicted”.16 It is as if the individual risks of suicide are somehow constrained by the population rate of suicide, instead of the population rate being simply the sum of individual risks. This idea was popular among scientists in the second half of the nineteenth century.17

It is not necessary to believe in such stark ideas in order to see that population health may be more than the sum (or average) of the health of all individuals making up that population. There are two ways in which this can be true—one in which population health is defined to be different, and one in which population health (despite a similar definition) is found to be different from the sum of the health of individuals.

Health and disease are usually seen to be properties of individual organisms: a human being (or a cat, or a plant) can be healthy or ill, and in case of illness of a human being doctors will try to identify the underlying “disease”. Since Virchow, “disease” is not seen as an independently existing entity, but as an attribute of an organism—a set of abnormal manifestations which result from reactions of the organism to a wide variety of disturbances, and which produce some kind of disadvantage in the organism’s functioning.18

In biology, the organism is just one of the many levels of organisation at which life processes can be studied. Organisms consist of organs, organs consist of cells, and one can easily think of healthy organs and sick cells. Similarly, organisms themselves are part of even larger systems, that is, of populations and ecosystems.19 Can we conceptualise sick populations? Perhaps we can, and not only in a metaphorical sense. For example, the Russian population exhibits “abnormal manifestations” (a high mortality rate among middle-aged men) which result from “reactions to disturbances” (a high prevalence of excessive alcohol consumption, caused by widespread demoralisation and a culture permissive of alcohol intoxication), and which produce a “disadvantage in its functioning” (great losses to labour productivity).20 The main requirement is that we see populations as “systems” (interactions between interdependent components controlled by positive and negative feedback mechanisms), whose collective functioning (reproduction, growth, prosperity, etc.) can be impaired.

But even if we define population health more simply as the aggregate of the health of all individuals making up that population, it can be seen that population health will not necessarily be a linear function of individual health. Take the example of infectious diseases: because one case will lead to another, (aggregate) future incidence will be more than the sum of (individual) current cases.21 More generally, transmission of the causes of disease between individuals (microorganisms, suicidal thoughts, violence, smoking, perhaps obesogenic behaviour22) leads to positive feedback loops generating “emergent” properties at the aggregate level, which cannot be readily deduced from what happens at the individual level. All positive feedback mechanisms (not only direct transmission of disease between individuals, but also indirect effects of disease on others’ health, eg, through economic performance) will let population health diverge from the aggregate of individual health statuses.23

“Sick populations” thus exist alongside “sick individuals”, and not only in a metaphorical sense. But the main question is whether this leads us to new knowledge about the causes of ill-health, and to new entry-points for public health interventions. It is on this issue that controversy has arisen, and Rose’s idea that we need to study characteristics of populations, not characteristics of individuals, has become a central theme in what some have called the “epidemiology wars”.24

This dispute, which raged in the second half of the 1990s, is about what are the most important causes of disease. Many epidemiologists prefer to study specific environmental exposures, health behaviours, biomedical characteristics and other “proximal” causes of disease, which are specific to the disease at hand and which can readily be examined with individual-level data in within-population comparisons. These are to be given priority, because of the greater scientific certainty about the role they play in disease aetiology.25

Others, echoing Rose, criticise this approach and argue that the more “distal” or “upstream” causes which will typically be identified in between-population comparisons, such as poverty, social cohesion or economic development, are more important because they offer greater potential for prevention strategies.26 A preoccupation with individual-level risk factors makes modern epidemiologists “prisoners of the proximate”.27 But “Should the mission of epidemiology include the eradication of poverty?” “The further upstream we move from the occurrence of disease towards root causes, the less secure our inferences about the causal path to disease become. Even if our inference is correct, intervention with respect to upstream causes may be less … effective than intervention closer to disease occurrence.” “Given the scope of the task, sympathy might go to the epidemiologists who prefer to focus on a comparatively simple problem, such as the causes of cancer.”28

HOW TO BE A MODERN VIRCHOW

Whatever the merits are of Geoffrey Rose’s big idea,29 the idea that “medicine” needs “politics” to improve population health is more popular than ever. During the past decades, the idea that health needs to be brought into these political arenas has become part of mainstream public health. A recent document entitled Health in All Policies, prepared for the European Commission, has outlined these ideas in more detail.3 As a matter of fact, this idea already has a strong foothold in many modern textbooks of public health, and “influencing government policy” has become a standard ingredient of handbooks of public health practice.30

When we look at the great victories of public health of the twentieth century, there are indeed many examples of interventions and policies that were decided upon in the political arena. Although they have been described as “silent victories”, in the sense that the lives saved and years extended by public health were anonymous,31 many interventions and policies were controversial and required extensive debate before they were implemented. Obstacles to be overcome included resistance to constraints on personal freedom, powerful economic interests, inequitable distributions of economic and social resources, and tensions between national and local authorities.32

Control of infectious diseases through safe drinking water supplies and sanitation often required decisions by municipal governments—decisions in which Virchow was involved in Berlin. Many other measures, such as introduction of mass vaccinations, prevention of occupational exposures and injuries, introduction of water fluoridation, motor vehicle safety measures and tobacco control, were implemented through special legislation and required the allocation of tax money. Although the development of these measures was largely a matter of scientific and technical progress, they could not be implemented at a larger scale without passing through a stage of political decision-making. Often, these decisions were controversial.32

While not all public health issues are inherently politically controversial, a naive observer cannot fail to notice that the outcome of political action to promote population health is rather uncertain. Politics is a struggle between conflicting ideologies and interests, in which health provides only one of many types of argument. Politics operates on a timescale governed by elections and media attention, which is at odds with the greater timescale at which population health and its determinants can be expected to change. An emphatically political approach to public health may also in the long run prove to be a self-defeating strategy, because of the dangers of politicisation. Politics is divisive, and long-term support for public health can be eroded as well as strengthened by recurrent political debates.33

How far should one go? Readers must decide for themselves, perhaps thinking of an imaginary “ladder of political activism” with four rungs. The first or lowest rung is that of political passivism: information on health risks and opportunities for health improvement is exchanged within the health sector only, and politicians are only informed if they ask for it. On the second rung, public health professionals actively disseminate relevant information among politicians, for example by addressing their reports to the government, by drawing the attention of the media and by participating in advisory committees. If they choose to rise to the third rung, public health professionals will try to directly influence the political process, for example by lobbying and by actively engaging politicians of specific political parties. On the highest or fourth rung, public health professionals become politicians themselves, and try to obtain positions in government or parliament to reach their objectives.

Many public health professionals will probably feel most comfortable on the second rung, but Virchow was among those who went to the top of the ladder, and he was (and is) in good company. Suppose that some readers would like to do the same—which political party should they choose? Evidence-based decision-making is even more difficult here than it is elsewhere, because there is almost no empirical evidence on the association between political traditions and population health. The little that there is, however, suggests that socialist or communist parties (eg, in the case of Cuba or China) have done relatively well in the Third World.34 In high-income countries, social–democratic parties appear to have done better than Christian–democratic or liberal parties.35 It is difficult to be sure about the causality of these associations, if only because populations consistently voting for social–democratic parties must also be different in many other respects. There is also no clear evidence that these countries have smaller health inequalities,36 but the results are certainly intriguing.

Is there a modern Virchow? Interesting Virchovian resonances can be found in the life and works of Bernard Kouchner. He took part in the Paris revolt in May 1968, but decided later in the same year to join a Red Cross mission into Biafra. This turned out to be what the trip to Upper Silesia was for Virchow. In this province of Nigeria, a civil war had broken out in 1967, and a famine caused 600 000 deaths in 3 months. Kouchner concluded that the Nigerian government was to blame, because it followed a policy of exterminating the Biafran people, but the Red Cross wanted to maintain a neutral stance. After his return to France, he published a report and later decided to found Médecins Sans Frontières in 1971. This non-governmental organisation speaks out about the political decisions which sometimes cause humanitarian disasters, and was awarded the Nobel Peace Prize in 1999.37

Later, Kouchner became a full-time politician, and developed into a strong advocate for the right to interfere in the “internal affairs” of nations for humanitarian reasons. This droit d’ingérence has been adopted to some extent in international affairs, and was put into practice in the former Yugoslavia, particularly in the action by the North Atlantic Treaty Organization (NATO) to stop the fighting in Kosovo in 1999. Kouchner became High Commissioner for Kosovo, in order to lead the transition to a peaceful situation. Kouchner embodies the globalisation of social conscience, which is perhaps best illustrated by his pleas for a system of global social security.38

As this article shows, Virchow’s legacy is still very much alive. His statement that “Medicine is a social science, and politics nothing but medicine at a larger scale” combines Guérin’s idea of “social medicine” with Bentham’s vision of legislation as “the art of healing practised upon a large scale”, and still resonates in modern public health. His idea that medical doctors make ideal politicians may be out of date, but the notions that whole populations can be sick and that political action is sometimes needed to improve population health still hold, although not necessarily in Virchow’s strong formulations.