Part 17

3. Data obtained from experiments conducted under the above qualifications is inconclusive, but presents little evidence of the value of mixed vaccines in protecting against influenza. There is, however, an indication that mixed vaccines used prior to the arrival of the epidemic will lessen the number and the severity of secondary pneumonias, and will probably lower the death rate to a small degree.

4. The army pneumo-lipovaccine apparently offers some protection against primary infections with types I, II and III pneumococci, and a somewhat lesser amount of protection against secondary pneumococcic infections with these strains following influenza.

5. While it is impossible to say that the large number of influenza cases developing almost immediately after vaccination would not have occurred anyway, it is at least suggestive that a temporary break occurs in the resistance after the inoculation, and that unusual care should be taken by persons who have been recently vaccinated, particularly when they are in the midst of an epidemic disease.

PART II. GENERAL PROPHYLACTIC MEASURES

One of the most remarkable things about the 1918 pandemic was the great rapidity with which it spread to all parts of the world. From the report of the first cases which landed in Boston until the epidemic arrived in San Francisco the time consumed was less than two months, and the peaks of the two epidemics were just about one month apart. Apparently no part of the world escaped. Asia, Europe, Africa, North and South America, and some of the remote islands of the Pacific, all reported large epidemics, with high mortality and great suffering. The deplorable failure of precautionary measures in controlling the spread, or at least in limiting the disease, may be offset in a measure by the unusual conditions under which almost everybody had been living. Vast numbers from all over the world were gathered together because of the war. Thousands of men were housed together in army camps or in training cantonments. Other thousands were doing relief work or engaged in the manufacture of munitions. Most of those at home were doing double duty, and were on a severe nervous strain. Everyone everywhere was working to the limit and was consequently fatigued. The necessities of war had cut down the amounts of food generally, and sugar and fat rations particularly. Traffic, both between nations and at home, had never been so great nor accommodations so insufficient. So that it is likely that all of these and many more changes in the daily routine of individuals led to a condition of lowered resistance, and at the same time increased their chances of exposure. One point, at least, stands out prominently, and that is that “influenza as it occurred clinically during the first great wave was different from those cases which appeared later.” This was seen in the acuteness of the onset, in the severity of symptoms, and in the high mortality rate. Therefore, any measure which afforded protection, if only for the time being, is worthy of retrial.

In view of the fact that recurrences have followed closely in the wake of all former influenza epidemics, and with the hope of stimulating concerted investigation of preventive measures, the American Public Health Association (57), at its meeting in Chicago in December, 1918, appointed a committee to outline “a provisional working formula, based on the facts and opinions brought out at the meeting.” A summary of the opinions as taken from the report of the committee is given here. They reported that the disease was probably due to some micro-organism or virus as not yet identified; that while it was known as “influenza,” it was not known to be identical with the disease generally known under that name; that there was no known laboratory method of differentiating it from ordinary colds, bronchitis, etc.; that there was no known laboratory method of determining when a patient ceased to be infective; and that the deaths from influenza were due to secondary pneumonia resulting from an invasion by one or more forms of streptococci, or by one or more forms of pneumococci, or by the so-called influenza bacillus or bacillus of Pfeiffer. Because of the clear and concise manner in which this report brings out the opinions held, at the time, by a majority of the medical profession a portion of the report is given here verbatim.

“Evidence seems conclusive that the infective micro-organisms or virus of influenza is given off from the noses and mouths of infected persons. It seems equally conclusive that it is taken in through the mouth or nose of the person who contracts the disease, and in no other way except as a bare possibility through the eyes by way of the conjunctivæ or tear ducts.

“If it be admitted that influenza is spread solely through discharges from the nose and throats of infected persons, finding their way into the noses and throats of other persons susceptible to the disease, then, no matter what the causative organism or virus may ultimately be determined to be, preventive action logically follows the principles named below, and, therefore, it is not necessary to wait for the discovery of the specific micro-organism or virus before taking such action.

“1. Break the channels of communication by which the infective agent passes from one person to another.

“2. Render persons exposed to infection immune, or at least more resistant, by the use of vaccines.

“3. Increase the natural resistance of persons exposed to the disease by augmented healthfulness.”

The ways and means of carrying out these principles are many and varied, and it is merely the intention of this paper to put together a sort of digest of some of the more important arguments for and against some of the seemingly more important measures proposed.

Methods Proposed for Breaking the Channels of Communication

(a) Rigid quarantine for all persons suffering from the disease and all contacts. During the epidemic quarantine was advocated by many people. It was pointed out that the disease spread most rapidly in camps, in ships, and in quarters generally where large numbers of persons were closely associated; that it was quite as contagious and more rapidly fatal than most diseases which are regularly quarantined; that while it was admitted that there is no laboratory method to make certain the diagnosis, and no method of telling how long convalescents are capable of transmitting the disease, as there is, for instance, in diphtheria, still there is no question of the value of the arbitrary quarantine used in measles, scarlet fever and smallpox, all of which are diseases in which the parasitic causes are not known. Further, the opinion was expressed that complete isolation and quarantine would not only protect the community from influenza, but that it would also in a measure protect the patient from contact with numerous outside strains of pneumococci and streptococci, and so lessen secondary infection and reduce the general mortality.

There are many reasons why quarantine is not applicable in epidemic influenza. Most important of all is probably the inability to make certain the diagnosis, especially during the early stages in light cases. This would work detrimentally in several ways. Really ill patients would delay calling a physician until late, for fear of unnecessary quarantine. Many needless and unjust quarantines would result when the diagnosis was uncertain and the physician anxious to carry out quarantine measures efficiently. Many patients would have contacts running about and infecting their neighborhoods while a delayed diagnosis was being made. Influenza was so contagious during the epidemic that it would have necessitated general quarantine not only of all infected persons but also of all contacts to have obtained any favorable results, and since nearly everyone was either a patient or a contact, all lines of business would literally have been paralyzed by the procedure. If it is true that the infected person is most dangerous to others before he has developed symptoms himself, he is a carrier impossible of detection and control. Points in favor of the hypothesis that infected persons spread the disease before they develop symptoms are found in the following facts. As the disease passed from community to community officials became alert for the appearance of the first case. In army barracks and in large institutions it was often possible to determine the first case at its development. The case was, in many instances, removed at once and isolated, but I have seen no instance in which such a measure was successful in curbing the disease. As subsequent cases appeared they were likewise immediately removed, but the cases continued to spread just the same. Bloomfield (38) cited the incident of a student who spent a few hours visiting his sister in a part of the country where there had been no influenza. He appeared well at the time, but six hours after his return to school he developed influenza. Two days after the contact the sister came down with the disease. On the other hand, he told of a student who did not contract the disease, though he slept for two nights in the same bed with his roommate, who had returned to school with a well-developed case of influenza. The unsuccessful attempts to transmit influenza in the experiments of Rosenau (37), McCoy (37a) and others already cited would indicate that the cases from whom the material was taken were no longer infectious, although some of them had been showing symptoms for only about 12 hours. Bloomfield observed that the general use of face masks in the wards did not alter the course of the epidemic, and stated that if face masks are protective, infection from early unisolated cases must be assumed.

Provided influenza is generally transmitted during the period of incubation, a theory which seems consistent with the facts, rigid quarantine for epidemic influenza is impracticable and probably useless.

Partial Isolation by Means of the Cubicle System

The so-called cubicle system consists in the dividing of rooms, or more particularly of wards, into small compartments by means of suspending sheets from wires so that each bed is separated from its neighbor. Capps (39) reported favorably on the method as used at Camp Grant, where sheets or halves of tents were suspended from wires or from the mosquito netting frames which were a part of the standard beds. Doctors, nurses and attendants were forced to wear masks in the wards, and patients were not allowed out of the cubicles without them. In discussing this paper Thayer emphasized the value of screening, masking and the wearing of gowns, and also recommended thorough washing of the hands between the examination of each two patients; and Emerson called attention to the fact that the first demonstration of the cubicle system as an adequate means of preventing acute respiratory diseases was made at the Pasteur Institute of Paris, where it had been in operation for 10 years. The latter stated that the system had been used in various hospitals in America and was essential for the care of diphtheria, measles and scarlet fever. He further indicated that if the technique of personal cleanliness of nurses, doctors and attendants could be perfected, it was probable that the height of the cubicle partition could be reduced to that of a “red string.” The method certainly seems worthy of consideration and trial, particularly in large general hospitals and public institutions.

The Use of the Face Mask

The question of the value of wearing a gauze mask over the mouth and nostrils during an influenza epidemic is still an open one. Masks, however, have been found useful in protecting against some other diseases of respiratory origin. In December, 1917, Weaver (40) reported favorably on the use of gauze masks in the Durand Hospital of Infectious Diseases. The masks were used by nurses in attendance upon patients with contagious diseases, and also by patients who were convalescing from diphtheria, meningitis or pneumonia and who were in the same wards with those having other respiratory diseases. In a later article Weaver (41) stated that by the use of masks they had been able to reduce the percentage of diphtheria carriers among their nurses in the diphtheria wards to 5.2 per cent., as compared to the average of 23.25 per cent. during the 20 months immediately preceding their adoption of their use. He recommended the general use of masks for physicians when in contact with all types of respiratory diseases. In March, 1918, Capps (39a) reported encouraging results in the control of infections through the masking of all patients at Camp Grant. During the epidemic the wearing of masks became quite general, and was very popular in many sections.

Several sets of laboratory experiments have been carried out recently to determine whether the masks are of practical value or not. The experiments have generally consisted in spraying cultures of living bacteria over sterile bacterial plates which were protected by one or more layers of gauze. A number of variations were made in the manner in which this was done: (a) the distance between the nozzle of the spray and the mask was varied, and the distance between the plate and the mask kept constant; (b) the distance between the plate and the mask varied, and the distance between the nozzle and the mask kept constant; (c) the use of masks both over the nozzle of the spray and over the plate being kept constant, and the distance between the two masks varied. In a somewhat different set of experiments the mask was placed over the mouth of a person, who was told to talk or cough over an agar plate, and the bacterial plate being held at various measured distances from the face. By counting the number of colonies which developed upon the plates it was possible to get fairly reliable data as to the efficiency with which the bacteria were intercepted by the gauze. Weaver (42) found that if enough gauze was used, it would filter out all of the bacteria passing from the spray in the direction of the plate. The efficiency of the mask being in direct proportion to the fineness of the mesh and the number of layers employed. Doust and Lyon (43) made a series of experiments to determine the distance through which droplets are carried when expelled under different circumstances. They found that in ordinary speech infected material is projected for about four feet, and that during coughing the material is carried about ten feet. They demonstrated that masks of medium meshed gauze, two to ten layers thick, worn by the person coughing did not prevent the passage of infectious material into the air, but that a three-layer buttercloth mask was much more efficient. Haller and Colwell (44) used three distinct sets of experiments—one with the mask over the mouth of the patient, one with the mask over the plate, and the third with masks over both—and concluded that a five-layer mask made up of 24 × 20 mesh protected the plate in the second series of experiments. They suggested marking one side of the mask, so that it would always be worn with the same side out. Leete (45), in England, by a similar series of experiments concluded that a dry mask of six to eight layers of butter muslin worn by a contact would protect him against droplet-carried infections. Dannenberg (46) suggested making the gauze mask over a copper screen wire frame to give it shape and keep it away from the mouth, thus keeping it relatively dry. All observers agree that masks while dry are more efficient than they are after they have become moist.

The efficiency of the mask has also been widely discussed from the clinical standpoint. Mink (47) in discussing their use at the Great Lakes Training Station said that he had no objection to the mask as it is “intended to be worn,” but that as it “was worn” by the medical corps men at the station 8 per cent. of those who used the mask developed influenza, as compared to 7.75 per cent. of those who did not; 30 per cent. of the dental officers at the station developed the disease in spite of the fact that they were all accustomed to wear masks during their work. In discussing the mask Vaughan (48) said: “With reference to the mask, I am strongly of the opinion that we have overestimated its value. * * * When I went to Camp Devens they were not using the mask. I called the doctors together and told them its use was not compulsory, but I said: ‘Every doctor who took care of cases of pneumonic plague and did not wear a mask died from it, and every man who cared for pneumonic plague cases and didn’t wear a mask did contract it.’” They were then allowed to choose for themselves. It has been pointed out that the epidemic dropped off at once in San Francisco with the universal compulsory use of the mask on the street, but it is also said that the epidemic in Los Angeles, which ran a course parallel to that in San Francisco and in which masks were only indiscriminately used, began to drop off simultaneously. While it is difficult to get at the facts, it seems that, provided epidemic influenza is carried through the air or by means of droplets, the universal use of masks should decrease the number of exposures. The claim has been made that masks merely tend to prolong the epidemic, and that susceptible persons develop the disease after the epidemic proper has passed. If the mask will protect the susceptible individual until the virulence of the disease has decreased, it will better that individual’s chances for recovery, and so is worth the trouble.

General Closing Orders

In most large cities orders were issued closing churches and theatres and prohibiting public gatherings of all kinds. In New York these places of public gathering were not closed, and it has been pointed out, as an argument against closing orders in the future, that the death rate there was less than in Boston, Philadelphia, Pittsburgh, etc. Copeland (49), of the New York Board of Health, stated that the unventilated picture shows were closed, but that the theatres were used as places of public instruction. New York’s relatively low death rate was difficult of explanation, but it is very certain that it had nothing to do with the fact that closing orders were not in vogue. If it were possible to obtain the figures, it would be interesting, indeed, to compare the death rate from influenza among New York’s theatre-attending public during the epidemic with the death rate of the community in general.

Generally speaking, any unnecessary public gatherings are inadvisable during any epidemic. While our exact knowledge of the mode of transmission of influenza is incomplete, it is unquestionably a contact disease. People who have been exposed and who have not yet contracted the disease are known to have transmitted it to a third person. A certain number of people from infected homes will attend public gatherings as long as they are able, for it is impossible to get together any large group of persons all of whom are going to play fair. It is true that these meeting places may be used in a measure to allay panic and to instruct the public in health measures, but there are many efficient and far less dangerous methods of accomplishing the same results. Vaughan in discussing assemblies in large halls mentioned that in a hall at Camp Forest, which held 9,000 people, the individuals had a space of about 16 inches laterally between their noses. He pointed out that if many of them were talking, coughing or sneezing, the air contamination would soon become so great that it could make little difference whether there was a roof over the building or not. He emphasized the fact that it is just as possible to crowd men in the open as it is indoors. Ventilation is undoubtedly an important factor, but it cannot correct overcrowding. As far as the educational value of the public gatherings was concerned, it may be observed that regular attendants of theatres and moving-picture houses during the year of 1918 had become quite accustomed to appeals regarding all sorts of public movements from speakers who appeared between the acts, or pictures, but that the closing of these places threw a wholesome scare into them which made them pay far closer attention to prophylactic measures than almost anything that could have happened. “Object-lessons are always superior to didactic teaching.” In Chicago a new argument for the closing of theatres was advanced. It was said that with no place to go many people retired earlier and obtained more than their accustomed amount of rest. It was believed that this aided in increasing their natural resistance. The argument that the closing of these places served only to delay the epidemic is an argument in favor of the measure, because the virulence of the disease decreased rapidly as the epidemic progressed.

The Closing of Schools

Boards of Health generally were opposed to the closing of the public schools. This position gave rise to innumerable clashes with anxious parents. The health authorities took the position that children were relatively insusceptible to influenza; that while they were quiet in a well-ventilated schoolroom they were little exposed; that those who coughed or sneezed could be examined at once, and that daily school inspection would lead to early discoveries of all cases, so that doctors and nurses could take immediate steps to treat the patients and to protect the families from which they came. Copeland advocated the continuance of the schools in New York, and based his position on the fact that out of 1,000,000 children in New York City 700,000 came from tenement homes. He believed these children were far better off in school, where they received daily medical attention, than upon the streets or in unhygienic homes.

In Pittsburgh the school children were quizzed as to the number of sick at home, and this gave valuable information on the stage of the epidemic. They were sent home with printed warnings against sneezing, coughing and spitting, and were thus used as a means of instructing their parents. The Pittsburgh schools were kept open until the sickness of a number of teachers and the withdrawal of many scholars made it advisable to close.