In April, an epidemic of influenza exploded in the Far East. Starting in Hong Kong, it spread thousands of miles in all directions in less than two months. As we watch it spread, we ask ourselves: Will this epidemic burn itself out—or is it the forerunner of a worldwide plague which may kill millions of people before it dies away?
Influenza, a disease of the respiratory tract, is spread from person to person by direct contact, through breathing, coughing, speaking, and sneezing. It is so highly infectious that many thousands of persons in a city may be attacked at the same time, and it spreads rapidly along lines of communication from one population center to another. The disease varies in severity from being almost asymptomatic to one that may cause death within a few days.
Influenza is the only disease causing worldwide epidemics in modern times. Indeed, this disease spreads all over the world so rapidly that “pandemic”—a special word meaning worldwide epidemic—is used to describe it. Pandemics of severe influenza occur about four times every hundred years. The last pandemic began in the early spring of 1918, when a wave of localized epidemics passed over the continent of Europe. Because of Spain’s neutrality in World War I, we received most information about the early 1918 epidemic from that country. As a result, in the United States the disease was popularly called “Spanish influenza.”
The cause of the 1918 pandemic of influenza is still unknown. It is supposed that the pandemic was due to a virus. Viruses are tiny protein molecules that infect the insides of cells and are too small to be seen with an ordinary microscope. Research techniques available in 1918 were not developed enough to identify the suspected virus. Since that time, enormous scientific advances have been made. We have learned to grow viruses in animals and in chick embryos. Now we are also able to photograph most viruses with the electron microscope.
The first successful isolation of an influenza virus took place during an epidemic in 1933. That year, doctors in England were able to grow the virus in a rodent called a ferret. The virus obtained from throat washings of human influenza patients produced a typical disease in ferrets. Since then it has been possible to isolate a virus from every subsequent epidemic of influenza.
We may be reassured that during the present summer the epidemic will be relatively mild, because the complicating germs do not flourish at this time of year as they do in the colder months. Even in the severe 1918 pandemic, the disease in the first wave, during the summer, was relatively mild. We may expect the present wave of relatively mild influenza to die away in the late summer. We do not know whether this will be the end of the epidemic or whether it will recur in a second, more serious wave of disease as in 1918–19.
If we are to derive maximum benefit from our knowledge of influenza, we must not delay. The interval between now and early autumn, when respiratory disease increases, gives us time for preparation. We must use this time well. It is not likely that enough vaccines for every resident of the United States will be available in time to meet the epidemic; therefore, priorities will have to be established. Vaccines may have to be allotted to older people and also to persons suffering from chronic heart and lung disease.
If a severe epidemic occurs, the maintenance of essential services in each community will be a major problem. An influenza pandemic is nothing more than warfare naturally produced. If an epidemic of influenza does occur here, it will provide a good test for our civil defense services.
From “The Influenza Epidemic,” which appeared in the August 1957 issue of Harper’s Magazine.
