Part 11

When the sample was removed for standardization it contained not only a thick suspension of Pfeiffer bacilli, but also bits of agar and blood-stained debris. It was necessary to rid the suspension of the gross contamination, and this was done at first by filtering it through sterile glass wool filters, and later by centrifuging it at slow speed for about 10 minutes. The suspension then contained little but the Pfeiffer bacilli, and was placed in the Hopkins tube and centrifuged for ½ hour on the sixth contact of the rheostat. This gave the per cent. of Pfeiffer bacilli in the suspension, and the necessary dilutions to make 1,000,000,000 per cubic centimeter were readily determined. The Hopkins tube consists of a centrifuge tube, with a capillary tube sealed on at the smaller end. The centrifuge tube is graduated in 10 c.c., 5 c.c. and 1 c.c. amounts, and the capillary portion is graduated in 0.01, 0.02, 0.03, 0.04 and 0.05 c.c. amounts. To standardize the vaccine, 10 c.c. of the sample was centrifuged in the tube and the amount of sediment read on the capillary scale. If the amount of bacilli fell between the graduations, an additional amount of sample was added, so that the sediment reached one of the graduated lines, the exact amount of sample added being noted. The percentage of the suspension could thus be determined by dividing the number of c.c. of sample used into the amount of the sediment obtained, and the number of bacteria calculated according to Hopkins table. The table available to us did not list the Pfeiffer bacillus, but according to it a 1 per cent. suspension of staphylococcus contains 10 billion organisms to the cubic centimeter, and we estimated that Pfeiffer bacilli were about half the size of staphylococci. This assumption was borne out by a number of Wright’s method counts on standardized suspension of bacilli. We, therefore, calculated that a 1 per cent. suspension of Pfeiffer bacilli should contain about 20 million organisms. Then, if 10 c.c. contain 0.02 c.c. of bacterial sediment, the per cent. was calculated by taking 0.02/10 = 0.2 per cent., the strength of the suspension. If 1 per cent. contains 20 billion, then 0.2 per cent. contains 4 billion per c.c. In order to get a 100 million per c.c. suspension, it would be necessary to dilute the original suspension 40 times.

Every method of standardization is more or less inaccurate, but the above described method gave a fairly uniform product. Drying and weighing is claimed by many to be more accurate, but even with this procedure a fair amount of non-bacterial sediment is present in the material to be weighed.

After the vaccine was completed, cultures were made from the final dilutions and were watched for 48 hours. Mice and guinea pigs were injected with the first samples to make certain that the material was non-toxic. Two laboratory employees also volunteered and received full doses before the first batch of vaccine was released. The first five litres were turned over to the Red Cross on October 31, one week from the day the work was begun. In three more days the laboratory reached a capacity of 10 litres a day, and on the fifth day the order was received to discontinue preparation of the vaccine.

Relatively little of our vaccine was given out, and in the rush it was not possible to determine which physicians had been given our vaccine and which had received commercial mixed products, so there is no data on its protective powers.

As soon as we found that there was no call for prophylactic vaccines, we planned some animal experiments; but inasmuch as we were unable to get our cultures of Pfeiffer bacilli virulent enough to kill mice or guinea pigs, the minimum lethal dose could not be determined, and without it it was impossible to determine the protective value of the vaccine. Mr. Purwin, in our laboratory, injected a 25–gram mouse intravenously with 2 c.c. of a milk thick suspension of Pfeiffer bacilli without killing the animal. He was successful in getting a small needle into the tail vein and in slowly injecting the whole amount. The mouse was sick for about 36 hours, but entirely recovered. Guinea pigs were insusceptible to very large doses. Had we succeeded by means of a vaccine in completely immunizing a man against Pfeiffer bacilli, we still would have been uncertain that he was immune to influenza in its “epidemic” form.

The absence of virulence in our laboratory strains may not mean that the cultures were non-virulent when first isolated, but it suggests the uselessness of attempting to make active vaccines from strains kept on artificial media for months or years, such as those commonly offered for sale by commercial houses.

The loss of virulence in strains that have been isolated for some time is interesting in the light of Parker’s (12) work upon toxine production by Pfeiffer bacilli. She found that toxic filtrates appeared in infusion broth cultures in from 6 to 8 hours, and that 2 c.c. of a 20–hour filtrate would kill a medium-sized rabbit in from 1 to 3 hours. It was also found that the poison deteriorated so rapidly that, in order to determine its toxicity, the tests had to be made on the same day that the filtrate was obtained. Parker succeeded in making an anti-serum against the poison, which appeared to be antitoxic for it both in vitro and in vivo. This work is interesting, and may be a step toward the development of a practical prophylactic serum.

_Conclusion_

From the above data, it is apparent that there is very little to indicate that an immunity to epidemic influenza is conferred by the use of a prophylactic vaccine composed of inert Pfeiffer bacilli alone. If a desirable vaccine is to be obtained through the use of these organisms, there must be radical changes in the mode of preparation of the vaccine or in the size of the doses given.

_The Attempt to Protect Against Epidemic Influenza by the Use of Mixed Vaccines_

For some years commercial houses have been carrying mixed vaccines for the treatment of colds, which they called influenza vaccines. These preparations were made up usually of six or more different varieties of bacteria, and all of them were of similar composition. There was more or less variation in the doses, both as far as the total number of bacteria and the relative number of the different types were concerned. A typical example of a so-called “mixed influenza vaccine” may be given about as follows:

B. Influenza (Pfeiffer) 25 to 400 million per c.c. M. Catarrhalis 25 to 400 million per c.c. B. Friedlander 25 to 400 million per c.c. Pneumococci 25 to 400 million per c.c. Streptococci 25 to 400 million per c.c. Staph. Albus-Aureus 50 to 800 million per c.c. ——— ———— Totals 175 to 2800 million per c.c.

These vaccines were recommended in the various catalogues for use either alone or together with other vaccines in the prophylaxis and treatment of common colds, and in acute and chronic diseases of the respiratory tract. As a matter of fact, they had been used very little in prophylaxis, and had failed to show very much value in treatment. In discussing these vaccines from the standpoint of treatment, R. M. Pearce (13) had the following to say: “A mixed vaccine for common ‘colds’ containing several organisms (staphylococcus, streptococcus, pneumococcus, micrococcus catarrhalis group, bacillus of Friedlander group, diphtheroid group, bacillus influenza) is one of the most recent bacterial ‘shotgun’ mixtures, which takes the chance of one lucky bull’s-eye in seven shots.” “No one can claim a scientific or even a common-sense basis for the treatment of a cold by such a mixture.” Catarrhal mixed vaccines of a similar kind were refused acceptance by the committee on “New and Non-efficial Remedies” of the American Medical Association, in June, 1918 (14), on the grounds that insufficient evidence of their therapeutic value had been furnished by their manufacturers.

While the above illustrates the status of “mixed vaccine” for therapeutic purposes, it is a well-recognized fact that it is possible to produce an immunity for most of the bacteria composing such vaccines, if killed cultures of the various strains are injected in sufficiently large doses. Again referring to Pearce’s article, we find the statement: “Prophylactic vaccination rests on a sound, scientific basis of experimental studies and clinical observation.”

The attempt to protect against epidemic influenza by the use of mixed vaccines was based largely on the following points. The medical profession was confronted by a rapidly approaching deadly epidemic, against which ordinary measures of control had failed. The epidemic was supposed to be due to a primary infection with Pfeiffer’s bacillus, but all of the fatal cases were found to have profound secondary or symbiotic infections, with one or more of the strains contained in the “mixed vaccines.” It was known that mixed bacterial proteins, even though they were not actually specific, possessed certain qualities of producing reactions unfavorable to infections in general, which were characterized by a temporary rise in temperature, by an increase in the number of leucocytes, and by a more or less demonstrable amount of active immunity against each one of the contained bacterial toxins. The artificial production of a leucocytosis was especially desirable, because a characteristic of epidemic influenza was the failure of leucocytosis on the part of the infected individual. In other words, mixed vaccines were used because they were the only available substances which offered the hope of creating a reaction against the secondary invaders which were so commonly the cause of death in influenza.

Since Pittsburgh’s experience with prophylactic vaccination had chiefly to do with the use of commercially prepared mixed vaccines, a brief history of the local experience with them may be of interest.

About the time that the first cases of influenza were being reported from the Pittsburgh district, articles on preventive vaccines as used in Boston and at some of the camps began to appear in the daily papers, shortly after which came the announcement that the Carnegie Steel Company was offering free vaccination to their employees and to the families of their employees. Dr. W. O. Sherman, chief surgeon for the company, advocated the use of the vaccine because he hoped to increase the immunity to secondary infection and to produce an active leucocytosis in the vaccinated individuals, and at the same time to allay panic among the employees at a time when an interruption of manufacturing and mining pursuits might be disastrous to the entire country; and he did it with the assurance that if the vaccine did no good, it would at least do no harm. He took steps to arrange for the collection of data by which he hoped to determine whether or not the vaccine as used by their company did any good. His report has not yet appeared. Other large corporations at once instituted prophylactic vaccinations with commercial “mixed vaccines.”

In contrast to the altogether laudable efforts of these companies to protect their employees, a complete history of the vaccine episode in this community necessitates the recounting of a very different phase in the matter. When it became known that corporations were vaccinating their employees, people in general naturally began to investigate. Physicians’ offices were besieged by persons who either demanded vaccination at once or wanted to know whether or not there was “anything in it.” Conscientious physicians in their turn called up the offices of the medical societies, the various laboratories, and telegraphed everywhere trying to get some definite data before recommending the vaccine to their patients. It was impossible to answer the question definitely, because it was a new procedure and purely in the experimental stage. On the whole, the medical profession handled the situation in a competent and dignified manner, for the great majority gave vaccines only after a full explanation to the effect that its value was in doubt, or else refused to give it altogether. There were some, however, who were not conscientious, and the unscrupulous practitioner seldom had a better chance to impose upon the public. The demand for vaccine soon exceeded the supply, and it is claimed that there were doctors who gave any type of vaccine they could obtain without regard to its bacterial make-up or intended purpose. Anti-diphtheritic serum was given in many instances, and it is said that even normal salt was used. Statements to the effect that exorbitant sums were being charged and that guarantees of prevention were being made resulted in the Red Cross Society undertaking the distribution of the vaccine. To protect itself, the Medical Society issued the following notice in the weekly bulletin for October 26, 1918:

The Society wishes it understood that at present there is no vaccine, serum or inoculation which will secure anyone against influenza. It is desirable that everyone should avoid hysteria and consider only the reports which are officially given out by the Health Department, since of late various methods of prophylaxis and treatment have found their way into the daily newspapers, and these may prove harmful rather than do good.

Almost simultaneously the daily papers published the report of Surgeon-General Blue, of the United States Bureau of Public Health, which expressed practically the same opinion. It was not the intention of either of these articles to criticise the practice of vaccination, but merely to warn the public against profiteering and fraudulent guarantees. They had the unexpected effect, however, of causing people to completely lose faith in prophylactic vaccines, and in many instances to become actually antagonistic to them. It was during this period that the preparation of vaccines from pure influenza strains was undertaken, under supervision of the County Society and for distribution through the Department of Public Health. Two days after the first supply of this vaccine was ready the Red Cross authorities telephoned that there was no further call for vaccine. The man in charge of the distribution stated concretely that “the bottom had dropped out of the vaccine business.” A few days later the Department of Health issued an order to stop the preparation of the vaccine.

Many pharmacies, having small supplies of vaccines, realized the great call for it and the difficulty of obtaining a new supply, and were also guilty of commercialism. Certain of the large biological product companies were no exception. One house issued a hand-bill, printed in red on a yellow background, which stated: “Epidemic influenza is due to the influenza bacillus. The present epidemic of influenza has a tendency to develop pneumonia. The use of our influenza bacillus vaccine No. —— will abort the influenza and avoid pneumonia and other sequelæ. When pneumonia has developed, it can be reduced to less than one-third the mortality and duration usual with other methods of treatment,” etc. Practically all of the above statements are still unproven, and probably will never be shown to be true. Such a bulletin undoubtedly lays this firm of vaccine manufacturers open to prosecution under the law protecting against false and fraudulent advertising. Several fairly well-authenticated incidents occurred in which the representatives of vaccine houses offered factory managers and others share and share alike in the profits, if the brand of vaccine made by them was used. It is on such happenings as the above that the writer advocates legal measures, allowing Boards of Health to control the advertising of remedies and distribution of biological products during epidemics.

How much Pittsburgh will learn from the experience with vaccines will depend on the numerous analyses of data which were acquired during the epidemic.

_Data on the Prophylactic Value of Mixed Vaccines_

Proof of the prophylactic value of mixed vaccines for epidemic influenza depends entirely upon the results of its practical application to human subjects in times when the disease is prevalent. Animal determinations are out of the question, because it has not been possible to produce the epidemic form of influenza experimentally. If all people were equally susceptible and were equally exposed, it would be a simple matter to compare the number of vaccinated persons who developed the disease with the number of unvaccinated persons who contracted it; but since many thousands were vaccinated and some of them contracted the disease in spite of it, and a greater number of persons who were not vaccinated entirely escaped, the analysis is extremely difficult.

The time element is a big factor. In instances where vaccination was completed in a community before the epidemic appeared there, the figures are worth more than those in which vaccination was undertaken after the epidemic had become established. This is true, because the most susceptible persons in a community developed the disease as soon as they were exposed, the less susceptible ones were not attacked until later, and the insusceptible ones escaped altogether. Whenever vaccination is begun during an epidemic, the persons vaccinated for prophylactic purposes are necessarily chosen from those who have not yet developed an attack. The later in the epidemic that vaccination is begun, the greater will be the number of persons selected for vaccination from among those more or less naturally immune. Then, if the total number of cases among the vaccinated is compared with the total number of cases among the unvaccinated, the apparent value of the vaccine is increased; but the estimation is not a fair one, because the vaccinated group is unavoidably selected from among relatively immune persons, while the controls include all of the very susceptible people who were suffering from the disease at the time vaccination was begun. Where vaccination is begun after the epidemic is advanced, the only figures worth while are those obtained by a day-by-day or a week-by-week comparison between the number of cases developing among controls and the number of cases appearing among those vaccinated, and by beginning that comparison at a time subsequent to the day on which the prophylactic inoculations were completed.

Aside from the interpretation of the results there is possibly a more serious reason for objecting to the beginning of vaccination during an epidemic. This lies in the danger of producing a temporary negative phase in the patient, which makes him somewhat more susceptible to natural infection for a few hours immediately following each administration.

McCoy (15) outlined the requirements necessary for an ideal vaccine experiment as follows: 1. The community should be as large as possible, and should number at least 10,000 persons. 2. The conditions under which they live should be as nearly equal as possible. 3. The turnover, or rather the change in population, should be as small as possible. 4. The social service should be efficient and reliable, so that it can be definitely ascertained when anyone becomes sick and what the disease is from which he is suffering. 5. Fifty per cent. should be vaccinated before the epidemic arrives, and the other 50 per cent. should be held as controls.

No examples were found which came up to the above requirements, but there were some instances in which vaccination was completed before the epidemic appeared, and some in which we were able to get a week-by-week comparison between vaccinated and unvaccinated groups. Most of the data which has been reported shows that vaccination was begun about the last of the second or the first of the third week of the epidemic, and in some instances not until after the peak was passed. Add to this the fact that the vaccine was given in from three to four doses, at from three to seven day intervals—a course which required in the neighborhood of two weeks for completion—and it is obvious that the full protective powers of the vaccine were not acquired by the individual until the worst of the epidemic was over and the number of cases were rapidly subsiding.

In order to get the best understanding from these experiments, the data will be presented in three series: I. Those instances in which vaccination was completed before the epidemic appeared. II. Those instances in which it is possible to compare the relative occurrence of influenza in both the vaccinated and unvaccinated groups after vaccination was completed. III. Those instances in which vaccination was begun after the epidemic appeared and in which comparisons of total figures only are available.

_Series I. Those Instances in Which Vaccination Was Completed Before the Epidemic Appeared_

1. The only instance in the Pittsburgh community in which vaccination was completed before the epidemic appeared is that reported from the Dixmont Hospital, Dixmont, Pa., and furnished me through the courtesy of Dr. Hutchinson (16). The institution had a population of about 1,000 patients and 300 employees. Prophylactic vaccination was begun on October 20, and was completed about November 6. Each c.c. of the vaccine used contained 200,000,000 each of B. Pfeiffer, Micrococcus Catarrhalis, B. Friedlander, Pneumococci, Streptococci and Staphylococci, both Aureus and Albus. Four doses were given of 4 minims, 8 minims, 12 minims and 16 minims, respectively. Inoculations were carried out at four-day intervals. Owing to the isolation of the institution from the general community, the first case did not appear until two weeks later—namely, on November 20. The results are shown by the table.

Population. No. of % of No. of % of Cases. Cases. Deaths. Deaths. Vaccinated 600 44 7.3% 0 0% Unvaccinated 700 69 9.8% 9 1.2%

None of the vaccinated patients developed pneumonia, though there were 15 cases among the unvaccinated.

This experiment shows a slight percentage in favor of vaccination, and indicates that there was some decrease in the severity of the secondary infections.

2. The experiment reported by McCoy, Murray and Teeter (17) showed quite opposite results from the above, and was an excellent example of a small though completely controlled test. In an asylum for the insane in San Francisco all of the patients under 41 years of age were divided into two groups—one group was kept as controls and the other was given a vaccine furnished by F. O. Tonney, of the Chicago Health Department. The vaccine contained 500,000,000 each of B. Influenza, Pneumococcus I, II and III, 1,500,000,000 Pneumococcus IV, 1,000,000,000 Streptococcus Hæmolyticus and 500,000,000 Staphylococci. Doses of 0.5 c.c., 1 c.c. and 1½ c.c., which were given at 48–hour intervals. Inoculation was completed on November 15, and the first case of influenza appeared on November 26. The table shows the result.

Vaccinated. Not Vaccinated. Persons in group 390 390 Cases of influenza 119 103 Cases of pneumonia 23 17 Number of deaths 10 7

3. The report of Minaker and Irvine (18) included several groups of men, the first two of which apparently belonged in our first series. They used a vaccine, each c.c. of which contained 5,000,000,000 B. Pfeiffer, 3,000,000,000 each of Pneumococcus I and II, 1,000,000,000 Pneumococcus III, 100,000,000 Streptococcus Hæmolyticus. In all, they vaccinated 11,179 persons.