The Great Influenza

by John M. Barry

  In Japan it attacked more than one-third of the population.

  The virus would kill 7 percent of the entire population in much of Russia and Iran.

  In Guam, 10 percent of the population would die.

  Elsewhere the mortality exceeded even that. In the Fiji Islands, 14 percent of the population would die in the sixteen days between November 25 and December 10. It was impossible to bury the dead. Wrote one observer, 'day and night trucks rumbled through the streets, filled with bodies for the constantly burning pyres.'

  A very few (very few) isolated locations around the world, where it was possible to impose a rigid quarantine and where authorities did so ruthlessly, escaped the disease entirely. American Samoa was one such place. There not a single person died of influenza.

  Across a few miles of ocean lay Western Samoa, seized from Germany by New Zealand at the start of war. On September 30, 1918, its population was 38,302, before the steamer Talune brought the disease to the island. A few months later, the population was 29,802. Twenty-two percent of the population died.

  Huge but unknown numbers died in China. In Chungking one-half the population of the city was ill.

  And yet the most terrifying numbers would come from India. As elsewhere, India had suffered a spring wave. As elsewhere, this spring wave was relatively benign. In September influenza returned to Bombay. As elsewhere, it was no longer benign.

  Yet India was not like elsewhere. There influenza would take on truly killing dimensions. A serious epidemic of bubonic plague had struck there in 1900, and it had struck Bombay especially hard. In 1918 the peak daily influenza mortality in Bombay almost doubled that of the 1900 bubonic plague, and the case mortality rate for influenza reached 10.3 percent.

  Throughout the Indian subcontinent, there was only death. Trains left one station with the living. They arrived with the dead and dying, the corpses removed as the trains pulled into station. British troops, Caucasians, in India suffered a case mortality rate of 9.61 percent. For Indian troops, 21.69 percent of those who caught influenza died. One hospital in Delhi treated 13,190 influenza patients; 7,044 of those patients died.

  The most devastated region was the Punjab. One physician reported that hospitals were so 'choked that it was impossible to remove the dead quickly enough to make room for the dying. The streets and lanes of the city were littered with dead and dying people' . Nearly every household was lamenting a death and everywhere terror reigned.'

  Normally corpses there were cremated in burning ghats, level spaces at the top of the stepped riverbank, and the ashes given to the river. The supply of firewood was quickly exhausted, making cremation impossible, and the rivers became clogged with corpses.

  In the Indian subcontinent alone, it is likely that close to twenty million died, and quite possibly the death toll exceeded that number.

  Victor Vaughan, Welch's old ally, sitting in the office of the surgeon general of the army and head of the army's Division of Communicable Diseases, watched the virus move across the earth. 'If the epidemic continues its mathematical rate of acceleration, civilization could easily,' he wrote in hand, 'disappear' from the face of the earth within a matter of a few more weeks.'

  Part IX

  LINGERER

  CHAPTER THIRTY-ONE

  VAUGHAN BELIEVED that the influenza virus came close to threatening the existence of civilization. In fact, some diseases depend upon civilization for their own existence. Measles is one example. Since a single exposure to measles usually gives lifetime immunity, the measles virus cannot find enough susceptible individuals in small towns to survive; without a new human generation to infect, the virus dies out. Epidemiologists have computed that measles requires an unvaccinated population of at least half a million people living in fairly close contact to continue to exist.

  The influenza virus is different. Since birds provide a natural home for it, influenza does not depend upon civilization. In terms of its own survival, it did not matter if humans existed or not.

  *

  Twenty years before the great influenza pandemic, H. G. Wells published War of the Worlds, a novel in which Martians invaded the earth. They loosed upon the world their death ships, and they were indomitable. They began to feed upon humans, sucking the life force from them down to the marrow of the bone. Man, for all his triumphs of the nineteenth century, a century in which his achievements had reordered the world, had become suddenly impotent. No force known to mankind, no technology or strategy or effort or heroism that any nation or person on earth had developed, could stand against the invaders.

  Wells wrote, 'I felt the first inkling of a thing that presently grew quite clear in my mind, that oppressed me for many days, a sense of dethronement, a persuasion that I was no longer a master, but an animal among the animals' . The fear and empire of man had passed away.'

  But just as the destruction of the human race seemed inevitable, nature intervened. The invaders were themselves invaded; the earth's infectious pathogens killed them. Natural processes had done what science could not.

  With the influenza virus, natural processes began to work as well.

  At first those processes had made the virus more lethal. Whether it first jumped from an animal host to man in Kansas or in some other place, as it passed from person to person it adapted to its new host, became increasingly efficient in its ability to infect, and changed from the virus that caused a generally mild first wave of disease in the spring of 1918 to the lethal and explosive killer of the second wave in the fall.

  But once this happened, once it achieved near-maximum efficiency, two other natural processes came into play.

  One process involved immunity. Once the virus passed through a population, that population developed at least some immunity to it. Victims were not likely to be reinfected by the same virus, not until it had undergone antigen drift. In a city or town, the cycle from first case to the end of a local epidemic in 1918 generally ran six to eight weeks. In the army camps, with the men packed so densely, the cycle took usually three to four weeks.

  Individual cases continued to occur after that, but the explosion of disease ended, and it ended abruptly. A graph of cases would look like a bell curve - but one chopped off almost like a cliff just after the peak, with new cases suddenly dropping to next to nothing. In Philadelphia, for example, in the week ending October 16 the disease killed 4,597 people. It was ripping the city apart, emptying the streets, sparking rumors of the Black Death. But new cases dropped so precipitously that only ten days later, on October 26, the order closing public places was lifted. By the armistice on November 11, influenza had almost entirely disappeared from that city. The virus burned through available fuel. Then it quickly faded away.

  The second process occurred within the virus. It was only influenza. By nature the influenza virus is dangerous, considerably more dangerous than the common aches and fever lead people to believe, but it does not kill routinely as it did in 1918. The 1918 pandemic reached an extreme of virulence unknown in any other widespread influenza outbreak in history.

  But the 1918 virus, like all influenza viruses, like all viruses that form mutant swarms, mutated rapidly. There is a mathematical concept called 'reversion to the mean' this states simply that an extreme event is likely to be followed by a less extreme event. This is not a law, only a probability. The 1918 virus stood at an extreme; any mutations were more likely to make it less lethal than more lethal. In general, that is what happened. So just as it seemed that the virus would bring civilization to its knees, would do what the plagues of the Middle Ages had done, would remake the world, the virus mutated toward its mean, toward the behavior of most influenza viruses. As time went on, it became less lethal.

  This first became apparent in army cantonments in the United States. Of the army's twenty largest cantonments, the first five attacked saw roughly 20 percent of all soldiers who caught influenza develop pneumonia. And 37.3 percent of the soldiers who developed pneumonia died. The worst numbers came fr
om Camp Sherman in Ohio, which suffered the highest percentage of soldiers killed and was one of the first camps hit: 35.7 percent of influenza cases at Sherman developed pneumonia. And 61.3 percent of those pneumonia victims died. Sherman doctors carried a stigma for this, and the army investigated but found them as competent as elsewhere. They did all that was being done elsewhere. They were simply struck by a particularly lethal strain of the virus.

  In the last five camps attacked, hit on average three weeks later, only 7.1 percent of influenza victims developed pneumonia. And only 17.8 percent of the soldiers who developed pneumonia died.

  One alternative explanation to this improvement is that army doctors simply got better at preventing and treating pneumonia. But people of scientific and epidemiological accomplishment looked hard for any evidence of that. They found none. The army's chief investigator was George Soper, later handpicked by Welch to oversee the nation's first effort to coordinate a comprehensive program of cancer research. Soper reviewed all written reports and interviewed many medical officers. He concluded that the only effective measure used against influenza in any of the camps had been to isolate both individual influenza victims and, if necessary, entire commands that became infected: these efforts 'failed when and where they were carelessly applied' but 'did some good' . when and where they were rigidly carried out.' He found no evidence that anything else worked, that anything else affected the course of the disease, that anything else changed except the virus itself. The later the disease attacked, the less vicious the blow.

  Inside each camp the same thing held true. Soldiers struck down in the first ten days or two weeks died at much higher rates than soldiers in the same camp struck down late in the epidemic or after the epidemic actually ended.

  Similarly, the first cities invaded by the virus (Boston, Baltimore, Pittsburgh, Philadelphia, Louisville, New York, New Orleans, and smaller cities hit at the same time) all suffered grievously. And in those same places, the people infected later in the epidemic were not becoming as ill, were not dying at the same rate, as those infected in the first two to three weeks.

  Cities struck later in the epidemic also usually had lower mortality rates. In one of the most careful epidemiological studies of the epidemic in one state, the investigator noted that, in Connecticut, 'one factor that appeared to affect the mortality rate was proximity in time to the original outbreak at New London, the point at which the disease was first introduced into Connecticut' . The virus was most virulent or most readily communicable when it first reached the state, and thereafter became generally attenuated.'

  The same pattern held true throughout the country and, for that matter, the world. It was not a rigid predictor. The virus was never completely consistent. But places hit later tended to be hit more easily. San Antonio suffered one of the highest attack rates but lowest death rates in the country; the virus there infected 53.5 percent of the population, and 98 percent of all homes in the city had at least one person sick with influenza. But there the virus had mutated toward mildness; only 0.8 percent of those who got influenza died. (This death rate was still double that of normal influenza.) The virus itself, more than any treatment provided, determined who lived and who died.

  A decade after the pandemic, a careful and comprehensive scientific review of findings and statistics not only in the United States but around the world confirmed, 'In the later stages of the epidemic the supposedly characteristic influenza lesions were less frequently found, the share of secondary invaders was more plainly recognizable, and the differences of locality were sharply marked' . [I]n 1919 the 'water-logged' lungs' (those in which death came quickly from ARDS) 'were relatively rarely encountered.'

  Despite aberrations, then, in general in youth the virus was violent and lethal; in maturity it mellowed. The later the epidemic struck a locality, and the later within that local epidemic someone got sick, the less lethal the influenza. The correlations are not perfect. Louisville suffered a violent attack in both spring and fall. The virus was unstable and always different. But a correlation does exist between the timing of the outbreak in a region and lethality. Even as the virus mellowed it still killed. It still killed often enough that in maturity it would have been, except for its own younger self, the most lethal influenza virus ever known. But timing mattered.

  The East and South, hit earliest, were hit the hardest. The West Coast was hit less hard. And the middle of the country suffered the least. In Seattle, in Portland, in Los Angeles, in San Diego, the dead did not pile up as in the East. In St. Louis, in Chicago, in Indianapolis, the dead did not pile up as in the West. But if the dead did not pile up there as they had in Philadelphia and New Orleans, they did still pile up.

  *

  By late November, with few exceptions the virus had made its way around the world. The second wave was over, and the world was exhausted. And man was about to become the hunter.

  But the virus, even as it lost some of its virulence, was not yet finished. Only weeks after the disease seemed to have dissipated, when town after town had congratulated itself on surviving it (and in some places where people had had the hubris to believe they had defeated it) after health boards and emergency councils had canceled orders to close theaters, schools, and churches and to wear masks, a third wave broke over the earth.

  The virus had mutated again. It had not become radically different. People who had gotten sick in the second wave had a fair amount of immunity to another attack, just as people sickened in the first wave had fared better than others in the second wave. But it mutated enough, its antigens drifted enough, to rekindle the epidemic.

  Some places were not touched by the third wave at all. But many (in fact most) were. By December 11, Blue and the Public Health Service issued a bulletin warning that 'influenza has not passed and severe epidemic conditions exist in various parts of the country' . In California, increase; Iowa, a marked increase; Kentucky, decided recrudescence in Louisville and larger towns, and in contrast to earlier stage of epidemic disease now affects many schoolchildren; Louisiana, disease again increased in New Orleans, Shreveport, [in] Lake Charles height reached equalled last wave;' St. Louis 1,700 cases in three days; Nebraska very serious; Ohio recrudescences in Cincinnati, Cleveland, Columbus, Akron, Ashtabula, Salem, Medina' in Pennsylvania, conditions are worse than the original outbreak in Johnstown, Erie, Newcastle. The state of Washington shows a sharp increase' . West Virginia reports recrudescence in Charleston.'

  By any standard except that of the second wave, this third wave was a lethal epidemic. And in a few isolated areas (such as Michigan) December and January were actually worse than October. In Phoenix for three days in a row in mid-January, the new cases set a record exceeding any in the fall. Quitman, Georgia, issued twenty-seven epidemic ordinances that took effect December 13, 1918, after the disease had seemingly passed. Savannah on January 15 ordered theaters and public gathering places closed (for a third time) with even more rigid restrictions than before. San Francisco had gotten off lightly in the fall wave, as had the rest of the West Coast, but the third wave struck hard.

  In fact, of all the major cities in the country, San Francisco had confronted the fall wave most honestly and efficiently. That may have had something to do with its surviving, and rebuilding itself after, the massive earthquake of only a dozen years before. Now on September 21 public health director William Hassler quarantined all naval installations, even before any cases surfaced in them or in the city. He mobilized the entire city in advance, recruiting hundreds of drivers and volunteers and dividing the city into districts, each with its own medical personnel, phones, transport and supply, and emergency hospitals in schools and churches. He closed public places. And far from the usual assurances that the disease was ordinary 'la grippe,' on October 22 the mayor, Hassler, the Red Cross, the Chamber of Commerce, and the Labor Council jointly declared in a full-page newspaper ad, 'Wear a mask and save your life!' claiming that it was '99% proof against influenza.' By October 26, the Red Cross
had distributed one hundred thousand masks. Simultaneously, while local facilities geared up to produce vaccine, thousands of doses of a vaccine made by a Tufts scientist were raced across the continent on the country's fastest train.

  In San Francisco, people felt a sense of control. Instead of the paralyzing fear found in too many other communities, it seemed to inspire. Historian Alfred Crosby has provided a picture of the city under siege, and his picture shows citizens behaving with heroism, anxious and fearful but accepting their duty. When schools closed, teachers volunteered as nurses, orderlies, telephone operators. On November 21, every siren in the city signaled that masks could come off. San Francisco had (to that point) survived with far fewer deaths than had been feared, and citizens believed that the masks deserved the credit. But if anything helped, it would have been the organization Hassler had set in place in advance.

  The next day the Chronicle crowed that in the city's history 'one of the most thrilling episodes will be the story of how gallantly the city of Saint Francis behaved when the black wings of war-bred pestilence hovered over the city.'

  They thought that they had controlled it, that they had stopped it. They were mistaken. The masks were useless. The vaccine was useless. The city had simply been lucky. Two weeks later, the third wave struck. Although at its peak it killed only half as many as did the second wave, it made the final death rates for the city the worst on the West Coast.

  *

  With the exception of a few small outposts that isolated themselves, there was by early in 1919 only one place the virus had missed.

  Australia had escaped. It had escaped because of a stringent quarantine of incoming ships. Some ships arrived there with attack rates as high as 43 percent and fatality rates among all passengers as high as 7 percent. But the quarantine kept the virus out, kept the continent safe, until late December 1918 when, with influenza having receded around the world, a troopship carrying ninety ill soldiers arrived. Although they too were quarantined, the disease penetrated - apparently through medical personnel treating troops.