Other Talks in the Series: The Immune System - Key Concepts and Questions

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Hello, my name is Anthony Rees. I'm a chemist, turned biochemist. I was a university lecturer in molecular biophysics at the University of Oxford, and later Professor and Head of Biochemistry at the University of Bath. My field of interest is immunology with a special interest in antibodies. Since 2012, I've been writing about the history of antibodies and more recently vaccines. The lectures in this three-part series relate to the history of vaccines. In January of 2022, last year, my book on the history of vaccines was published, and it's from this book that I've selected a few examples of pathogens that have afflicted the human population over thousands of years. We'll look at some of the early curative and often crude measures used before the advent of modern medical technologies, and in particular, the seismic effect of vaccines on preventing human disease and reducing mortality.
Welcome to the third and last in this short series on the history of vaccines. Today we'll be looking at influenza and coronaviruses.
As you can see on this slide, I've said influenza, a pathogenic chameleon. You'll see why chameleon as we move forward.
Influenza is an RNA virus, but with a genome structure that encourages what we call strain diversification, and with it, of course, severe immunological consequences. It's a member of the orthomyxoviridae family, which includes seven genera. Four types of influenza virus, the A, B, C, and D, which you might have heard of, and three types of tick-borne viruses, thogotovirus, quaranjavirus, and isavirus. The last one infecting fish only. Influenza A is the most virulent and the B sub types, they cause seasonal epidemics of disease in many parts of the world, usually during winter, but less severe than influenza A. The C subtype type infections generally cause only a mild respiratory illness and rarely if ever cause epidemics. While the D subtype primarily affects cattle and isn't known to cause infection and illness in the human population, and we always have to say as yet. Emergence of novel influenza A variant subtypes has been the cause of a series of intermittent pandemics and epidemics over the intervening years since the notorious Spanish flu. That was a pandemic of 1918-1919, which had something like 500 million cases or morbidity of which 50-100 million deaths occurred. Some of the key epidemics and pandemics in recent times have been the Asian flu in 1957, where there were 1-2 million deaths, the range, of course, depending on data sources, but less fatal in the elderly. That was explained by them having residual immunity from an 1989 epidemic. The younger people, of course, would not have had that. The Hong Kong flu in 1968, around one million deaths. That had a high infection rate. But it could have been worse if not from the residual immunity from the 1957 virus. There were two waves of infection in the Hong Kong flu. A bit later in 1977, the Russian flu hit. And this was a pseudo pandemic. Pseudo because it only affected mainly those less than 25 years of age with the older persons already immune, hence the pseudo. I just maybe mention a note that there have been conspiracy theories on this particular Russian flu epidemic or pseudo pandemic, that this was an escaped virus from Chinese departures. Something we'll be talking about a bit later with coronaviruses, but of course not proven for the Russian flu. Then we have the swine flu pandemic in 2009, mitigated by the rapid development of vaccines. We'll have a bit more to say about this later.