Influenza is a virus. Of its four genera, three infect humans (influenza A, B and C). How did we come to ‘know’ this? This is the question that Michael Bresalier aims to answer in his wonderful new book. Bresalier argues that although the biological truth that influenza is a viral disease is an ancient reality, ‘medical and scientific knowledge of influenza … is historically recent, contingent on and contextualized through developments from the late nineteenth century to the 1940s’ (p. 5). Modern Flu seeks to centralize British laboratory science in how we have come to ‘know’ the viral nature of influenza. Influenza provides Bresalier with an important historical example of the ‘alignment and integration of virological knowledge with existing epidemiological, clinical, and pathological knowledge’ which he argues was ‘integral to creating the identity of a viral disease’ (p. 20).
Bresalier carefully guides the reader through a series of pivotal moments in the history of influenza research. He argues that before the twentieth century, the medical understanding of influenza was highly protean. Influenza was little more than ‘a plethora of respiratory, nervous, or gastral symptoms’ (p. 1). After a contextual chapter on nosology in the eighteenth and early nineteenth centuries, Bresalier traces the origins of ‘modern’ flu to the 1889–94 influenza pandemic, during which medical scientists established a ‘modern’ identity for the disease, constructed from bacteriological, clinical and epidemiological knowledge. That identity was ultimately wrong – contemporaries misattributed the cause of flu to the bacterium Bacillus influenzae (Pfieffer's bacillus) – but Bresalier sees this as an important moment in modernizing flu, establishing an identity for influenza that was ‘cause-based’ rather than ‘symptom-based’ (p. 104).
Bresalier then shows how collaboration between the Army Medical Service and the Medical Research Council (MRC) during the 1918–19 pandemic broke the stranglehold of Pfieffer's bacillus yet created new uncertainties about the disease's nature. ‘The pandemic had ignited interest in the possible role of a filterable virus and the general nature of such agents, yet the way forward was unclear’ (p. 162). Bresalier examines how the MRC sought in the 1920s to ‘transform viruses into workable laboratory objects and to develop new methods for their control’ (p. 162). Flu was at the centre and the pandemic was the catalyst.
Research on a different virus, canine distemper, at the National Institute for Medical Research (NIMR) laid the foundations for influenza virus research, but the inability to identify the virus left flu as protean as ever. It was not until 1933, when a team of scientists working at the NIMR ‘joined physicians and pathologists … in a crucial series of studies on influenza’, used ferrets as a proxy for humans, and at last brought influenza ‘within the realm of experiment’ (p. 253). As a result, a disease formerly ‘defined by symptoms or environments, by airs, constitutions, or bacteria’ was now finally ‘defined by a virus’ (p. 3).
The ‘viralization’ of flu turned on the fulcrum of 1933, Bresalier argues, but he notes that scientists struggled ‘to make a new laboratory entity – the influenza virus – relevant to constituencies outside the laboratory walls’ (p. 254). By 1935, the viral nature of flu was clearly articulated in medical textbooks, but clinicians saw limited important in its viral nature. The global import of viralizing flu did not become clear until the Second World War, which intensified the need for international collaborations with Americans, who discovered through experimentations with mass vaccination the continued need for surveillance of this ‘constantly changing’ virus (p. 315).
Bresalier concludes by returning the epicentre of influenza research to Great Britain, with the establishment of the World Influenza Centre (WIC) in 1948, which grew out of the NIMR. The WIC played a vital role as a locus of surveillance and made ‘influenza visible in an entirely new way’ (pp. 320–1). The World Influenza Programme (WIP) that followed made clear that influenza was ‘a highly variable, mutable, and ever-changing’ virus that required ongoing scientific study, because it ‘could emerge from and spread to any part of the world, and, under the right conditions, become pandemic’ (p. 352). Thus Bresalier ends on a somber point worthy of further historicization: despite knowledge of the virus, in the second half of the twentieth century, ‘deep inequalities in the distribution and access to crucial medical resources’ remained (p. 353).
Modern Flu is a welcome addition to the history of influenza, which tends to focus on the history of pandemics, like Mark Honigsbaum's Living with Enza (2009) or Niall Johnson's Britain and the 1918–19 Influenza Pandemic (2006). Although the 1918–19 pandemic serves as a pivot point that began the transformation of the identity of the disease from bacterial to viral, Bresalier places the pandemic in a much broader context, one which would give impetus to the work at the NIMR that would ultimately be successful in viralizing flu. Therefore perhaps it would be better to compare Modern Flu to George Dehner's Influenza (2012). But whereas Dehner is interested primarily in the public-health responses to influenza in the twentieth century, Bresalier lays out the important foundations for a public-health response in the laboratory. We had to ‘know’ flu before we were able to combat it, which Bresalier acknowledges in his coda in which he briefly extends his analysis past 1950.
Modern Flu is deeply researched, and the ways in which Bresalier meticulously establishes the networks of knowledge as scientists came to understand ‘modern flu’ in the first half of the twentieth century are compelling. The text is also supplemented with an astonishing forty-four figures. This book belongs in the library of any historian of virology or infectious disease, and is a must-read for historians of science and medicine/public health. At nearly four hundred pages of text the book is perhaps a bit too much for undergraduate students; however, the individual chapters are clear in each of their arguments and are organized in such a way that they would be easy to assign in smaller parts to students.
