Epilogue of the 1918-1919 Influenza Epidemic - 1921

Trolley Car Windows Were Kept Open to Prevent the Spread of Spanish Influenza

Trolley Car Windows Were Kept Open to Prevent the Spread of Spanish Influenza Which Did Much to Slow up War Progress in This Country. This Photo Was Taken in Cincinnati. the Practice of Keeping Windows Open Was Nationwide During the Influenza Epidemic. Photo by Felix J. Koch Taken Circa 8 November 1918. National Archives and Records Administration RG 165-WW-269B-22. NARA ID # 45499333. GGA Image ID # 15063e3ec7

Dr. Hamer has visualized the present state of our knowledge of epidemic influenza in a manner which can scarcely be improved upon. We, therefore, quote him at length: "It seems to me that, during the last thirty years or more, we have been making fairly steady uphill progress along the road which constitutes the boundary between the county of epidemiology and the county of bacteriology, and that we have at length reached, at a height considerably above sea level, the foot of the mountain, on the very top of which lies hidden the secret of an 'epidemic constitution' and now we are face to face with a parting of ways.

Straight ahead is the frowning height, its summit in cloud. On the right hand stretches away a fine road skirting the base of the mountain. Along this road we have recently seen Dr. Brownlee whirled away in his new car 'periodogram.'

We are all hoping to hear more from him, but as he is still insisting upon the primary, if not the exclusive, importance of continuous variation in the virulence of the germ, we have to realize that for the time Dr. Brownlee's road is going down-hill.

On the other hand, on the left, there swerves away, through the territory of the old epidemiology, another fine road, which has been explored more particularly by believers in 'skiey influences.'

So far as it has been traced this road is as flat as flat can be, but of course there is always the possibility that after a while it will begin to rise, as it skirts round the mountain, and leads to a good vantage point from which to start climbing.

At the risk, however, of being laughed at, I venture to bring under notice the very rough and at first sight unpromising ground directly in front of us. Along this can be seen two obscurely marked sheep tracks proceeding at any rate onwards and upwards.

One diverges slightly towards the left hand and it has been followed at various times by De Schweinitz and others, naturalists bent on collecting 'ultravisible viruses;' the second track, directed rather more to the right, has been explored by Reiner, Müller, Massini, Penfold, and others, workers at the problem of discontinuous variation by 'mutation.'

As a matter of fact I have reason to believe that two travelers, each of whom follows one of these tracks, will keep in sight of and after a while will find that they are approaching one another, and will ultimately meet at a small and retired upland farm; then after passing some dogs and following the track until clear of all stone walls, they will come right out in open ground on the face of the mountain and can start straight up the steep.

But it must here be pointed out that there remains to be considered a fourth method of approach to the mountain, the most direct of all; but that is by aeroplane and is of course only open to those trained in metaphysics and statistical methods. Investigators thus equipped are able to rise in the air, to survey with careful scrutiny the whole of the ground beneath them and to make the best use of details of information obtained by scouting parties below.

It is to be hoped that at no very distant date a survey of the top of the mountain will thus become an accomplished fact. Meantime, those who cannot fly may find useful employment in examining the track beyond the farm.

There is the chance there of picking up facts relating to such questions as the parasites associated with a parasite,' symbiosis, and the like; take, for example, a suggestion made fourteen or fifteen years ago that the influenza organism may at one time live in association with Pfeiffer's bacillus, at another with the Micrococcus catarrhalis, and so on; or the throat distemper organism may be yoked now with the diphtheria bacillus and now with the Streptococcus conglomerate. (Is that, I wonder, now to be regarded as a concept or as an occurrence or happening?)"

At best our knowledge of the cause and manner of spread of influenza is fragmentary and insufficient. Attempts to outline a system of control and prevention based upon present concepts are met with many discouragements.

The next pandemic will not be prevented. The disease will surely return. If the interval be sufficiently long it may find us quite as unprepared as we were in 1918. Discouraging as the outlook is there are many bright points upon which we must base our hopes for future results.

The difficulties are many: First the diagnosis of influenza is difficult either in the individual case or in the form of a mild epidemic. Even in 1918 the identification was often not definitely made until after weeks had elapsed. Second, we know little concerning the mode of transmission of the disease. We speak of "respiratory infection."

We believe that the transmission is by a mechanism similar to that for measles, but we have never experimentally transmitted either disease. The short incubation period places us at a great disadvantage.

Were the interval between the occurrence of the first case and the development of additional cases as long as it is in measles, the problem of isolation and quarantine would be simplified. As in measles the disease is probably very early infectious, presumably before acute symptoms develop.

The majority of cases of influenza are ambulatory. Many individuals do not take to their beds, but continue about their work, spreading the disease wherever they go.

Again, we are ignorant of the period of infectiousness. Dr. Meredith Davies has made observations indicating that a patient becomes non-infectious within one week after the temperature has become normal. How many influenza patients remain isolated throughout this period?

A carrier state probably exists and plays a most significant part in the spread.

Yet another drawback is the apparent wide susceptibility to the disease. Were individuals definitely immunized by one attack the proportion of susceptibles would be lessened, their concentration in a population would be decreased, and the probability of their being exposed would be proportionately diminished.

An additional difficulty is that after an epidemic has once become prevalent, we must combat not only the virus causing the disease but also the secondary invaders.

Epidemiologic work has shown that crowd gatherings are instrumental in the spread of influenza. The density of population has not been as definitely proven to be a factor. Crowding, however, does play a part.

Close crowding in communities must facilitate the spread, but pandemics of influenza were known before the great metropolis existed. Hygienic conditions play their part in the etiology. Finally, in the presence of every serious epidemic we must also combat the tendency to panic in the population.

Anticipatory or Preventive Measures

It is erroneous today to speak of measures for the prevention of influenza in a community. We cannot prevent the disease.

At most, we can anticipate the occurrence of an epidemic and take precautionary measures by which the spread and the severity of the disease may be minimized.

First and foremost comes education. Education of the public, of the medical profession and of health authorities. "Scare headlines" in the newspapers during epidemics should be discouraged.

Health cartoons are of value, but when they express only partial truths, they cannot but do some harm. General education in hygienic methods and in a knowledge of the spread of contagious diseases has already been most productive.

Many methods by which the public intelligence could be reached arc as yet untried. A daily paper in Boston devotes two columns a week to a discussion of public health problems, under the title of "The Clinic."

The statements appearing in these columns are nearly always the truth and are not exaggerations. There are discussions of recent scientific work of interest to the reading public.

As has been emphasized by Carnwath, a page devoted to methods of maintaining the health of the community would probably be of more immediate value than are the many pages devoted to financial statements, "such as the price of Mexican Eagles or of Peruvian Corporation Preference."

The organization of health services to combat unexpected epidemics would be of great assistance. In times of peace, prepare for war. In all but the largest cities the health authorities are generally so free from contact with epidemics and are so pressed with routine that they do not organize in readiness for an epidemic which may not come.

There should be a closer co-operative organization between health officials and practicing physicians, so that the latter may aid to a greater extent in the public health work.

The physician co-operates in furnishing information required by the health officer, but too frequently takes little interest in what further is done with this information.

The medical profession should be made to understand the importance of public health work, should have a general comprehension of the methods used in its execution and should particularly develop a sympathetic and co-operative mental attitude.

The medical societies of the country should be so organized that at a moment's notice their membership can be mobilized for the defense of the community. There is much that the practicing physician does not know about influenza.

One of the leading internists in one of our largest cities, during the 1920 epidemic, refused to call his cases influenza and treated them as mild "grip." It is stated that he lost an unusually large number of his patients.

There are still many who believe that the two diseases are not identical. Not only is this detrimental to the patient, but as it results in failure to isolate the sick it is, detrimental to the community.

Nursing groups should be organized to aid at a moment's notice.

Much work has been done and great experience gained by both the physicians and the nursing organizations during the last epidemic. Now is the time to prepare for the next epidemic or pandemic.

With the remembrance of 1918 fresh in our minds we can establish a working system, while if we delay until the expected arrival of another epidemic much of our painfully acquired knowledge will have been forgotten.

Opinion differs as to whether influenza should be made a reportable disease. The added expense would be not insignificant. This particular malady presents the additional complication of being difficult of diagnosis. The records would at best be inaccurate.

The author believes that certain experiments in reporting the disease even in inter-epidemic times should be carried out. This should be done by competent epidemiologists who could later formulate plans for the permanent reporting of the disease. We will discuss this further under the heading, "Constructive Research."

The use of vaccines has been tried. In 1918 it was almost universally begun too late—after the epidemic had become prevalent. Prophylactic vaccination should be inaugurated before the disease actually becomes epidemic.

Vaccination, particularly against the secondary invaders, is entirely rational. It may not prevent influenza, but it may protect against the serious complications in individuals and may prevent to an extent the spread of secondary invaders in the community.

Greenwood aptly remarks that, "In estimating the total effects produced upon morbidity and mortality by disease, the non-specific secondary invaders are as important as the specific causes.

The camp followers of an army may do more damage than the regular soldiers, and the same camp followers may ravage in the wake of different armies.

At a conference held at the London War Office, October 14, 1918, the subject of vaccination for influenza was discussed. It was decided that only three organisms should be employed in each case in the preparation of the vaccine; that these races should be recently isolated from cases of the disease developing during the course of the epidemic and that the microorganisms should be submitted to a rigorous study as to race and type.

The first dose should include 30,000,000 of Bacillus influenzae, 100,000,000 pneumococcus, 40,000,000 streptococcus; the second dose 60,000,000 Bacillus influenzae, 200,000,000 pneumonococcus, 50,000,000 streptococcus. The vaccine should be sterilized at 55° C. and one-half percent, phenol should be added. The administration should be at ten days' intervals.

In the United States the vaccines employed have often contained a greater variety of organisms. It is unnecessary to enumerate the results obtained by various investigators. Some have been mildly enthusiastic, while others have obtained no demonstrable benefit.

It will suffice to say that there has been no clear evidence that vaccination has been beneficial, but that the procedure has not been given a thorough trial. If the causative organism of the disease is eventually determined, vaccination will probably be attempted with it as antigen.

For the success of vaccination it is important that practically entire communities be inoculated, and that they be so inoculated before the development of epidemic prevalence.

Palliative Measures in the Presence of an Epidemic

An epidemic, once having obtained a start will run its course. Our attempts will be to lessen its extent and diminish its explosiveness. Or, more probably, we will best succeed by extending the duration and making the invasion less explosive.

We must know of its earliest appearance. Notification must be made by physicians to the health authorities in order that the earliest increase may be detected.

This again renders the reporting of the disease at all times an essential feature. The administrative control and the publicity to be given have already been discussed.

What general measures should be taken against the disease? Should the public schools be closed? Winslow and Rogers found that the orthodox methods of combating epidemics applied in Connecticut exerted no appreciable influence on the spread of influenza.

Bridgeport, Hartford and New Haven did not close their schools and suffered from death rates near the average for the State, lower than the rates which prevailed in cities like New London and Waterbury, which closed their schools.

No deductions can be drawn from this fact, however, because the closing of the schools in most cases was forced because of the severity of the outbreak.

The data obtained by Jordan indicate that schools were not important distributing centers for the infection. No explosive outbreak occurred in any one grade, and the four days of the Thanksgiving holiday evidently afforded more favorable opportunities for infection than did the days of regular school attendance.

Carnwath believes that in view mainly of the marked prevalence of the disease amongst school children, the balance of opinion is in favor of closure, even in densely populated urban districts. In the author's investigation there was a slightly higher incidence of the disease among children attending school than among those younger children who were not at school.

The spread is probably not facilitated so much in the classroom as it is on the playground. In the school room the children are constrained to remain at a certain distance from each other. Probably they would come into as close contact with cases if they were not at school.

Certainly it has not been demonstrated that the school room is a factor of great importance in the spread of influenza. It would, perhaps, be better not to close the schools in the presence of an epidemic, but to discontinue any congregation on the play grounds, and to discourage the grouping of children in play on the streets.

With children and with all individuals, large or small, a great factor in exposure and probably in the transmission of the disease is the necessary crowding on street cars and in public buildings. Here is a potent source which requires deep study and new treatment.

Some cities have with partial success attempted lessening the congestion in public conveyances at the beginning and closing of business hours by arranging with the various offices, stores, etc., that the opening and closing times occur at different hours.

In order that this procedure may work it is important that the employees of a factory or store which closes early must ride to their destination at the time of closing and not remain in the congested business districts. Here again it is a problem of educating the public to a point where they will co-operate intelligently.

It has been amply demonstrated that crowd gatherings markedly facilitate the spread of the disease. Mass meetings should be prohibited and gatherings in and out of doors should be discouraged. The public should be taught that the safest place is at home.

What instructions can we give to the individual for his own protection? There are at least six precautions based on scientific knowledge. They are:

  • First: Avoid crowds.
  • Second: Avoid crowding in the family.
  • Third: Sleep alone.
  • Fourth: Pay particular attention to personal hygiene.
  • Fifth:      Boil all dishes, etc., after meals.
  • Sixth: Do not eat in insanitary restaurants. Eat at home.

Should cases be isolated? Should they be quarantined until no longer infective? The experience of the last epidemic has rendered us pessimistic. We have found that isolation and quarantine does little or no good.

Institutions which were held under rigid quarantine for the first months of the epidemic were later invaded when discipline became lax. The disease thereafter spread often as extensively as it would have, had there been no delay.

But, on the other hand, there is record of some institutions in which the quarantine lasted throughout the epidemic and in which the inmates never became ill.

All of our past experience with infectious diseases leads us to believe that isolation of cases should be enforced. The experience of 1918 should not cause us to change from this point of view. Up until now the procedure has been without results.

It has been nearly impossible to enforce it. Further study must be made before any definite conclusion can be reached.

The same in general may be said regarding disinfection after recovery of a case of influenza. Today most people believe that disinfection is unnecessary.

The work of Lynch and Gumming, if correct, would indicate the contrary. The possibility of transmission through inanimate objects has not as yet been completely eliminated.

The efficacy of face masks is still open to question. Certainly the face mask as extensively used during the 1918 epidemic was of little benefit and in many cases was, without doubt, a decided detriment. The same mask was worn until it was filthy.

It was not worn in such a way as to be a protection. Even had the nose and mouth been efficiently protected, the conjunctivae remained unprotected.

The work of Maxcy and of Vincent and others has demonstrated the importance of the naso-lachrymal duct as a possible portal of entry into the respiratory tract proper.

After cultures of Bacillus prodigiosus were sprayed upon the ocular conjunctivae these organisms have been recovered from the nose within five minutes, from the nasopharynx within fifteen minutes and from the feces within twenty-four hours.

One difficulty in the use of the face mask is the failure of co-operation on the part of the public. When, in pneumonia and influenza wards it, has been nearly impossible to force the orderlies or even some of the physicians and nurses to wear their masks as prescribed, it is difficult to see how a general measure of this nature could be enforced in the community at large.

If masks are to be used, they should be employed in the same manner as for protection against the plague. They should be made to cover the entire head. This procedure has been recommended particularly by Vincent and by Thorne.

It is safe to say that the face mask as used was a failure.

Problems for the Future -- Constructive Research

While pure epidemiologic study of influenza will not demonstrate the causative agent, it is the chief procedure upon which we can at present rely for improvement in our methods of combat.

Many important laboratory contributions have been made during the last two years. The majority have been without immediate value to the health officer. The author suggests in the following paragraphs a plan of study, based upon past epidemics and the experiences of the last pandemic, as epitomized in the preceding chapters.

During the exposition of this subject we have drawn certain conclusions and have developed some theories. We believe that they explain the facts correctly, but should the hypotheses prove not entirely correct the value of the following outline for study will be in no way impaired.

To become thoroughly acquainted with epidemic influenza in all its manifestations would require a lifetime of study. Knowledge of the disease would be greatly furthered if competent epidemiologists should see fit to devote their entire time to a study of the disease in its various ramifications.

The author suggests a research organization of individuals whose function it would be to become completely acquainted with influenza.

The organization should be under the direction of a competent board of epidemiologists. Under them would work several groups composed of epidemiologists, bacteriologists and others. There should be sufficient groups so that they might be distributed to diverse regions of the earth.

They should be equipped for travel, with mobile bacteriology laboratories and all the necessary equipment for epidemiologic surveys, so that at a moment's notice they could proceed to wherever an epidemic of any disease simulating influenza is reported to be prevalent.

The working groups would be under the administrative control of the central directors and would make their reports to them. All groups should be so distributed geographically as to have easy and rapid access to any community in which an epidemic might occur.

They would keep themselves informed concerning the disease prevalence in all communities under their jurisdiction.

This would be done through the co-operation of the civil health authorities and through the utilization of all other available sources of information. The central board should be constantly in touch with the groups, so that the infectious disease prevalence in all parts of the world would be known at all times.

Had such an organization been in existence during the last thirty years, every one of the so-called influenza epidemics reported in one place or another would have been investigated.

Detailed epidemiologic, statistical, demographic and bacteriology reports would have been made. It matters little how small or insignificant the outbreak appears to be.

Even the smallest have their characteristic features and are worthy of study. If we study epidemic influenza but once in thirty years, we will never become well acquainted with the disease. We must see it repeatedly and frequently.

If it does not exist during the intervals, we must study the diseases simulating it. It is surprising how much of the knowledge acquired in 1889 was forgotten by 1918. Even some of the more important features had passed from memory.

Thus we find statements in 1918 that the age morbidity was quite different from that in all preceding epidemics. Research into the literature of the past does not corroborate this impression.

If influenza is scattered throughout the earth in mild form, it would avail us but little to send a commission to Bokhara to study the endemic focus supposed by some to exist in Turkestan. Even though the disease were endemic in that country, one would not expect to discover epidemics there.

The general immunity of the population in the endemic area is probably increased. Nevertheless one unit might well be stationed in Turkestan, there to study the existing conditions regarding infectious diseases.

There would be ample work for all groups at all times. The study would not be limited to a consideration of infectious diseases. Sociologic conditions may be of importance. We have recorded instances of this. Wherever there is an unusual concentration of large masses of individuals the investigators should study the results of such concentration.

An advantage of this organization would be that the groups through their central bureau would establish an information bureau of infectious disease prevalence analogous to the popular weather bureau of today. They would report the presence of a cloud before it had appeared on the local horizon.

In the absence of any epidemics resembling influenza, there would be abundant opportunity for correlated work. We have mentioned the epidemiologic resemblances between influenza and certain other infectious diseases. Comparative study of any or all of them is of importance.

The bacteriologist and the immunologist would find plenty of material in the study of measles prevalence. The two diseases are so similar in their manner of spread, in the probable mode of transmission, in their clinical characteristics and in the results of laboratory attempts at transmission, that one must assume that the causative viruses are not dissimilar. Any new facts that we may gain concerning measles will be of value in the study of influenza.

Many years could be well devoted merely to a study of immunity in influenza.

The results obtained by this proposed organization for the investigation of influenza would be slow in achievement. The study is not of a type calculated to appeal to the popular imagination. Communities in which the dread of an imminent pestilence is not present would subscribe with some hesitation to appeals for pecuniary assistance.

Fortunately, however, there are in existence several organizations already well developed along these lines, organizations chiefly interested in certain other diseases.

There can be no doubt but that at the present time the financing of such a broad project could be arranged, and that the groups could be efficiently organized on the basis of experience already gained in similar projects.

Crookshank well remarks that our present epidemiologic intelligence service is hardly superior to that of a Meteorological Office which only gives warning of rain when unfurled umbrellas pass along the street.

Influenza will surely return. There will be mild epidemics within the next few years. In time another pandemic will arrive, and after it will come pandemic after pandemic.

In 1918 as in 1889 we were caught unprepared. Let us do our utmost to prevent the recurrence of this tragedy. To delay is to lose the valuable information gained during the last two years.

The future is not without well-grounded hope, but success will not be achieved until we have attained a much deeper understanding of the epidemiology of influenza.

Warren Taylor Vaughan, M.D., Influenza: An Epidemiologic Study, Section VIII: The Prevention and Control of Influenza, in the American Journal of Hygiene, Monographic Series No, 1, Lancaster, PA: The New Era Printing Company, July 1921, p. 234-244.

Return to Top of Page