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Chapter 9 - Smallpox




Col. Laurence A. Potter, MC, USA

In the past, war and pestilence went hand in hand, and smallpox changed the direction and outcome of many wars. For more than 150 years, man has had the tool with which smallpox could be virtually stamped out, but he has used the tool only with varying efficiency to control or limit the disease in some areas. The principal nations of the world have used vaccination to protect their troops so that smallpox did not affect the decisions, direction, or outcome of any of the various phases of the global war. Nevertheless, a slight, but avoidable, morbidity and mortality from smallpox did occur among United States Army troops. Furthermore, the possibility of an outbreak of smallpox among civilian populations in a global war must be a matter of concern and planning by those responsible for military operations. A study of the history of smallpox during World War II gives the basis for certain predictions.


Smallpox is one of the great epidemic diseases, worldwide in distribution, and capable of great explosive outbreaks. It occurs in two forms, the classical variola major of high virulence and the mild alastrim or variola minor. Vaccinia is rarely transmitted from man to man as a communicable disease.

Variola is transferred mainly by droplet infection but is also transmissible in fomites. In the classical form, the incubation period is almost invariably 12 days. Transmission of the disease is facilitated by crowding; hence the cases increase during the colder winter months, reaching a peak in the spring and falling off rapidly as summer approaches.

Complete immunity or protection for a limited period of years can be accomplished by introduction of the virus of cowpox into a small area of the skin of a susceptible person. An attack of smallpox, either the classical or mild form, usually gives lifelong immunity to both varieties.

Classical smallpox is endemic in certain areas, primarily Iraq, India, China, Mongolia, Manchuria, Mexico, and Portugal. Alastrim, the mild variety, is endemic in Africa, Europe, and the United States. Where alastrim

1 (1) Russell, F. F.: Smallpox and Vaccination. In Oxford Medicine. New Fork: Oxford University Press, 1942, vol. 5, pp. 553-592. (2) Gill, Clifford A.: The Genesis of Epidemics and the Natural History of Disease Baltimore: Wood, 1923. (3) Top, Franklin II.: Communicable Diseases. St. Louis: C. V. Mosby Co., 1947.


becomes endemic, the classical disease tends to die out and tends to recur only in explosive outbreaks traceable to new importations of the disease.

It is interesting to speculate as to the remote origin of smallpox. Arguments have been made for its probable origin in the paleo-Arctic province of Central Asia (Mongolia),2 but it may have originated in Africa. Alastrim, a better adapted form, was first recognized in Africa 3 Smallpox was probably derived from another animal host; it is poorly adapted in its classical form to humans, since it kills too many hosts.


In the past, the effect of war has been to cause flare-up of this dreaded disease resulting from movements of armies, dislocations of peoples, and, since Jenner, disruption of programs of control. The extent of these outbreaks has been relative to the magnitude of the dislocations and the extent of programs of vaccination or the presence of the immunizing effect of alastrim in the population.

Smallpox broke the siege of Mecca A. D. 570, and the returning army carried the disease into North Africa where it became endemic. The Moslem invasions carried it from North Africa into Spain4 where it remained endemic for centuries and only recently was supplanted by alastrim.

The subjugation of the American Indian resulted as much from the inroads of smallpox as from the fighting ability and superior weapons of the invaders. The weak settlements of New England could not have survived their early years had not the Indian tribes been riddled by smallpox contracted from the explorers and traders who preceded the settlers.5

The Franco-Prussian War was followed by the most furious epidemic of the 19th century. It has been estimated that 200,000 died of smallpox in France in 1869. The carrying of the disease into Germany, by French prisoners eventually resulted in the deaths of 140,000 people in Prussia, 170,000 in Austria, 143,000 in England, and lesser numbers in other parts of the world. The further the disease progressed from the seat of war, the easier it was to bring under control.6

After World War I, Germany passed through two more severe epidemics as a result of spread of smallpox from Russia.7

The armies of the United States have experienced smallpox in all their wars but in ever-decreasing amounts as care in the use of vaccine and the organi-

2 Stallybrass, Clare O.: The Principles of Epidemiology and the Process of Infection. London: George Routledge and Son, 1931.

3 See footnote 1 (1), p. 151.

4 See footnote 2.

5 Stearn, Esther Wagner, and Stearn, Allen E.: The Effect of Smallpox on the Destiny of the Amerindian. Boston: Bruce Humphries Inc., 1945.

6 See footnote 2.

7 Fabre, J.: Smallpox Prevalence Throughout the World During and After the Second World War. Epidemiol & Vital Statist. Rep. 1: 268-289, June 1948.


zation of programs of immunization have improved and as alastrim has supplanted the virulent classical smallpox as an endemic, or at least recurring, disease in the United States.

The Revolutionary War was fought before Jenner's great discovery of the immunizing effect of cowpox in 1796. Nevertheless, among the many diseases and infections which took so great a toll of American troops, smallpox was the one infectious disease which the medical men of that period understood and could combat with a measure of success. Their weapon was inoculation--a heroic and, to present-day thinking, wasteful method nevertheless effective in the prevention of disruption of an army in the field by smallpox. Protection by inoculation was not carried out completely in all areas, or at all times, with the result that smallpox played a major part in the defeat of the units attempting to take Quebec and hold Canada.8

There are no available accounts as to the incidence of smallpox during the 26-month Mexican War, nor are there statistics for the Army for the years 1847 and 1848. A very high incidence of smallpox among troops occurred in 1849 9 despite the fact that vaccine virus, which had been imported by Dr. Waterhouse of Boston in 1800, was being used routinely by the Army.

The next high peak of smallpox among Army troops occurred in 1864. The incidence was high throughout the whole period of the Civil War. There was a total of approximately 19,000 cases resulting in nearly 7,000 deaths during the war period.10

Smallpox took a much smaller toll during the Spanish-American War and the Philippine Insurrection. There had been no smallpox in the Army in 1896 and only one case in 1897. Smallpox among Negro laborers at Forts Barrancas and Pickins, Fla., and its prevalence in Columbia, S. C., in March, April, and May 1898 alerted the Army to danger and led to careful vaccination of volunteer troops at the time of their muster into the service of the United States. In spite of those precautions, the majority of cases and deaths occurred among the volunteer troops, with only a small number occurring among Regular Army troops. 11 There were 825 admissions resulting in 258 deaths (1898-1901) ; 674 of the admissions and 249 deaths occurred in the Philippines. 12

Before World War I, the Army had experienced a sharp increase in smallpox admission and death rates during war periods. During World War I, the admission rate was but little higher than the low rates experienced in the years immediately preceding the war. There were 853 admissions with 14 deaths.13 Of these, 789 admissions, resulting in only 1 death, occurred in the United States. The negligible mortality indicates the disease was variola

8 Duncan, L. C.: Medical Men in the American Revolution, 1775-1783.Army M. Bull. No. 25, 1931.

9 (1) Statistical Report on Sickness and Mortaility in the Army of the United States. Washington: A. O. P. Nicholson, 1856. (2) The Medical Department of the United States Army in the World War. Communicable and Other Diseases.Washington: U. S. Government Printing Office, 1928, vol. IX, pp. 357-386.

10 See footnote 9 (2).
11 Annual Reports of the Surgeon General of the Army, 1898 and 1899.Washington: Government Printing Office.
See footnote 9 (2).

13 See footnote 9 (2).


minor (alastrim), which had by this time, perhaps aided by varying programs of vaccination among the civilian population, supplanted variola major in the United States.14


The principal advances made during the period 1919 to 1941 which had or could have had an effect in lowering toward zero the number of cases of smallpox in the Army arose not out of a better understanding of the disease or in improvement of the vaccine, but in technologic progress in refrigeration (fig.3) and transport of the vaccine.

During World War II, refrigerators operated by electricity or a kerosene flame were present in numbers in forward areas as a part of the regular equipment of supply and hospital units. Regularly scheduled air transports oper ated from the United States to all theaters of war and were capable of rapid transport of vaccine adequately refrigerated by packing in dry ice (solid CO 2), which was easily available at the point of origin of air shipments of vaccine, when required.

FIGURE 3.- Use of matting and leaves to shield vaccine refrigerator from the sun, 25th Medical Depot Company, India, 1944.

14 See. footnote 2, p. 152.


Lack of understanding of the rapid deterioration of smallpox vaccine stored at temperatures above 0oC. often negated the advantage of adequate refrigeration and rapid, protected transport. Cases of smallpox among troops following their entry into a zone where smallpox was present in the civilian population sometimes resulted. In each such instance, revaccination with potent vaccine soon effectively prevented further cases. The major portion of the cases occurred after V-J Day and the end of combat action.

United States Army policy with respect to vaccination for smallpox during World War II was stated in Army Regulations No. 40-210, 15 September 1942; in Circular Letter No. 162, Office of the Surgeon General, 28 November 1942; and in War Department Technical Bulletin 114, 9 November 1944 (revised 28 February 1947). These regulations required vaccination against smallpox as soon as possible on entry into the military service, with revaccination at intervals of 3 years thereafter. In addition, revaccination was to be accomplished before departure for overseas duty unless the individual had been vaccinated within the 12-month period prior to departure. Vaccination was required, also, on exposure to smallpox or in the presence of an outbreak, regardless of the date or the result of the last vaccination.15

In World War I, combat and postwar occupation took place in one of the best protected areas of the world continental Europe. Most of the cases of smallpox occurred in the United States and were variola minor resulting directly from a considerable incidence of this disease in the civilian population of the Midwest.16 In the 20 years before World War II, improved local and State programs of immunization and the apparent low communicability of alastrim had resulted in a decline to a negligible incidence. However, during and immediately after the combat period of World War II, American troops entered most of the areas of the world wherein classical smallpox is endemic or recurs in epidemic form. The disturbance of war increased the epidemic potential and thus led to increased incidence in various areas of the world with consequent exposure of troops present in those areas. The low incidence (a total of 215 cases during the period from 1939 to 1947) among troops was remarkable. A single case overseas in 1942 was from the Middle East theater. There were 4 deaths among 15 cases overseas in 1943. No cases of smallpox occurred among Army troops in the India-Burma theater in 1943, but in 1944 there were 23 cases with 6 deaths from that area. The peak month, March, accounted for 14 cases and 3 deaths. There was a high incidence of smallpox among the civilian population of that area during the period. 17

In 1944, an outbreak of smallpox occurred which could have had serious repercussions over a widespread area. Early ill the year, seven cases of smallpox of a mild aviruleiit form occurred among civilian employees at the Army

15 Long, Arthur P.: The Army Immunization Program. In Medical Department, United States Army, Preventive Medicine in World War II. Personal Health Measures and Immunization. Washington: U. S. Government Printing Office, 1955, vol. III, p. 283.

16 See footnote 9 (2), p. 153.

17 Blumgart, H. L., and Pike, G. M.: History of Internal Medicine in India-Burma Theater. [Official record.]


airbase at Fortaleza, Brazil. Several of these employees were in daily close contact with transient military personnel passing through this installation en route between the United States and North Africa, the Middle East, and India. At the time of the incident, no known cases occurred among uniformed personnel either based at Fortaleza or transient through the base to points spread over half the globe. However, the potential implications of this occurrence are demonstrated by the following data on 155 Army personnel revaccinated as a direct result of the occurrence of the first case: 95 had a reaction described as vaccinia, 9 as vaccinoid, 39 as immune, and 12 had no noted reaction.18

From 1 January 1945 until the end of combat in August 1945, only 1 case of smallpox occurred in the Persian Gulf Command, 1 case occurred in the Mediterranean, and 1 case occurred in Europe. During this period, there were 13 cases with 4 deaths in the India-Burma theater. Two cases and one death occurred in February; 8 cases and 1 death occurred in March; and 3 cases with 2 deaths occurred in April.

All of the smallpox during these years occurred as sporadic cases among an otherwise completely protected uniformed population and were directly related to high incidences of the disease among the civilian populations of areas indicated. In these areas, the military population was very small in relation to the civilian population, and the soldiers were, as individuals either on or off duty, thrown into close contact with civilians. During the first winter of occupation, 1945-46, the same conditions existed in certain areas; a similar experience during this winter will be, considered in detail, since it has a direct relationship with and is, in fact, part of the war, since it is illustrative of any grouping of cases in the previous years, and since more exact detail is available. The most important outbreak occurred among occupation forces in Korea during the winter of 1945-46. 19

Prior to the movement of occupation forces into Korea from Okinawa and the Philippines, all immunization records were checked and personnel who had not been immunized against smallpox within 1 year were revaccinated.

The first troops landed in Korea early in September 1945, and additional units continued to arrive for several months. The first personnel eligible to return to the United States for discharge left early in October, and this process of returning individuals was a constant procedure throughout the winter. No substantial number of replacements for these, individuals arrived in Korea until the first of the year 1946, but thereafter replacements arrived in a more or less continuous flow throughout the remainder of the winter. The Army population was a continually changing one; furthermore, the total number of troops in Korea fluctuated greatly from week to week, and the age distribution among the Army personnel shifted steadily toward the lower age group (18-20), the older men being returned to the United States by virtue, of points based on length of

18 Letter, Capt. B. M. Kagan, MC, Epidemiologist, Headquarters, United States Army Forces, South Atlantic, Office of the Chief Surgeon, Recife, Pernambuco, Brazil, to Commanding General, United States Army Forces, South Atlantic, 4 Sept. 1944, subject: Report on Smallpox at United States Army Air Base, Fortaleza, Brazil.

19 (1) Boeck, V. 11. F.: Smallpox Among U. S. Soldiers in Korea. Bull. U. S. Army M. Dept. 6: 45-58, July 1946. (2) Boeck, V. H. F.: Smallpox Among U. S. Army Forces in Korea. J. Mil. Med. Pacific 2: 2-6, April 1946.


service, service overseas, campaigns, decorations, and number of children. Personnel who remained were younger men who came as replacements late in the war when the age for compulsory service was lowered. The replacements received in Korea in 1946 were nearly all in the 18-20 age group. Because of these considerations, the estimation of rates based on total population, especially age specific rates, is not feasible. The over-all morbidity rate for smallpox was well under 1 per 1,000 or those exposed during the 4-month period 1 November 1945 to 1 March 1946, inclusive. (The annual rate per 1,000 average strength was 1.8.)

As nearly as could be, determined, the program of vaccination of the civilian population 20 in Korea had been practically inoperative for at least 5 years; the vaccine manufactured in Korea presumably had been needed by the Japanese Army.

Korea was not a combat area during World War II, even in that early phase of it between the Japanese and Chinese prior to 1939. The country and its Japanese and Korean populations were relatively stable; at least, there were no mass movements into the area or within the area. Japanese troops moving through the country were transported directly on an excellent railroad system and were immunized against smallpox. When the war ended, this was changed. The Japanese capitulated a month before the entry of American occupational troops into Korea. On the date of capitulation, all industry stopped in Korea. Controls over the population ceased, and a great deal of movement within the country occurred. Furthermore, many Koreans had been employed by various Japanese agencies in north China and Manchuria, and many Japanese civilians were in these areas and in North Korea. These peoples began to move, in whatever manner they could, toward South Korea, Their movement was given impetus by the advance of Russian forces across Manchuria into Korea, north of the 38th parallel. This movement of refugees continued throughout the winter under conditions of indescribable. hardship, since most of the movement was, of necessity, on foot. Even during freezing weather, refugees were entering at the rate of several thousand each day into the American Occupation Zone from across the northern border. Other Korean refugees were being repatriated by ship from Japan, China, and other areas of the Pacific. This latter group of refugees, however, was not a great threat because they were processed through United States Army or United States Navy agencies before embarkation.

The stage was set for smallpox to occur in epidemic proportions among the civilian population, since there was a large pool of susceptibles into which would be introduced large numbers of refugees bringing highly virulent smallpox from the outer reaches of Manchuria and north China.

The first cases among civilians which came to the attention of the occupying forces began to occur late in October. During the 4-month period November 1945 to March 1946, inclusive, 84 outbreaks numbering 200 to 500 cases

20 Simmons, James S., Whayne, Tom F., Anderson, Gaylord W., and Horack, Harold M.: Global Epidemiology. Philadelphia: J. B. Lippincott Co., 1944, p. 151.


each were reported to Army authorities, and steps were taken to control them by intensive vaccination in the communities or localities where they occurred. Any estimate of the total number of civilian cases would be only a guess, but they occurred in all areas of Korea south of the 38th parallel, and were well distributed among the 19 million people. The incidence was unquestionably higher in the northern sections and along the main routes of travel of the refugees as they spread out over Korea returning to their home areas.

The first case among United States Army troops was diagnosed on 3 November 1945, but the actual date of onset of symptoms was 27 October. During November, 5 more cases occurred, with 2 deaths toward the end of the month. In December, there were 21 more cases and 9 deaths; these were followed by 6 more cases and 2 deaths in January 22 and 4 more cases and 1 death in February.After 6 February 1946, there were no further cases.

Immediately upon recognition of the first case, the patient's record indicated a recent immune reaction, revaccination of all troops and American civilian personnel in Korea was ordered. This procedure took some time because of delay in obtaining sufficient vaccine. Hospitals were directed to examine all admissions carefully for recent vaccinations and to revaccinate if any doubt as to the reaction existed. If a case broke out in a hospital, mass revaccination of all hospital personnel and patients was to be done immediately.

All persons entering Korea were to be vaccinated on arrival. This order was later modified; vaccination was required aboard ship just prior to debarkation. The purpose was to prevent possible exposure at the reception center before vaccination could be accomplished and to make doubly sure that all persons were vaccinated. Previously, some personnel had not been vaccinated on arrival because they did not go through the center before assignment.

Because of the continued incidence of smallpox in December 1945 and doubt as to the potency of the vaccine available from depots in the Pacific, sufficient vaccine to revaccinate the entire command was ordered shipped by air, packed in dry ice, directly from the United States. This shipment was received 21 January 1946. Since ambient temperatures in Korea at this time were below freezing, no difficulties were encountered in preserving the vaccine during its distribution throughout the command. A directive was sent out requiring that careful entry of the reaction be made on each individual immunization register and that, upon completion of the program, each major echelon commander would certify by letter to the commanding general of the occupying forces that each individual of his command had been revaccinated with the "Special Lot of U. S. Vaccine." No further cases of smallpox occurred among Army personnel following completion, during the first week in February, of this program with vaccine of known high potency. The outbreak of

21 See footnote 19 (1), p. 156.

22 In addition, an Australian merchant seaman, 30 years old, contracted smallpox in January. He had never been vaccinated. The case was diagnosed as variola, severe, and resulted in death.


smallpox in Japan was a direct extension of the Korean epidemic. Many Japanese were repatriated through Korea, and, while the majority were vaccinated before leaving Korea, many made the trip surreptitiously in small boats and thus evaded processing stations.

Within the first few weeks following V-J Day (September 1945), steps were taken to reassemble and place in operation the Korean vaccine laboratory and its equipment, which had been dismantled and moved a few weeks prior to American occupation. This laboratory immediately processed and packaged vaccine lymph found at the former site and then procured calves and began operations. By February 1946, more than a million doses per month were being produced. This vaccine, augmented by vaccine from Army sources as it could be procured (3 million doses-September 1945 to April 1946), was used initially to vaccinate all refugees being evacuated from, or entering, Korea. When civilian outbreaks of the disease began to occur, it was used as a focal attack to prevent further spread. All Koreans in the Government agencies and transportation systems were vaccinated. As vaccine became more plentiful, vaccination programs were carried out in the larger cities and other communities where considerable numbers of American troops were concentrated. By the end of 7 months, over 7 million of the 19 million Koreans in the American area had been vaccinated, and the program was continuing at an accelerated pace. The very cold winter weather compensated for the lack of refrigeration in preservation of the potency of the vaccine. It was contemplated that operation of the vaccine laboratory would be suspended during the summer months.

The small number of cases and the ever-varying size and composition of the command do not permit statistical evaluation designed to present statistically significant proof supporting basic conclusions or recommendations; however, the data and the general conclusions and impressions derived from these facts are pertinent to the discussion.

Distribution of patients by age ranged from 18 to 48.Of the 37 patients, 14 were 19 years of age. Of the 22 patients 21 years of age and under, 9 died, the case fatality being 40.90 percent. Of the remaining 14 patients, over 21 years, 4 or 28.57 percent died. The age of one patient who died was not available. Over-all case fatality was 37.84 percent.

Available home addresses indicated that 27 of the patients were from rural areas and that 9 were from urban areas, a ratio of 3 rural to 1 urban. Deaths were 12 rural and 2 urban, or a ratio of 6 to 1. This undoubtedly reflects variations in vaccination programs rather than previous experience with variola. One case occurred among Negro troops whose strength was approximately 4 percent of the command. The rural-urban composition of the Army population is not known, but it is hardly likely that personnel from rural areas exceeded in number those of urban origin.

The 36 patients on whom such data was available originated in 18 States. Forty-four percent of the patients were from 4 States: Ohio-6, Alabama-4,


Texas 3, California-3. None of these States required vaccination as a prerequisite to school attendance.23

The likely source of infection in 30 of the patients was the native population, for soldiers in Korea were thrown into close contact with the people of this heavily populated area. Four patients were exposed while in Army hospitals. One very mild abortive infection occurred in the medical officer who attended the, first Army patient. Two patients gave no history of contacts with civilians or with known cases.

The cases were differentiated clinically as follows: 3 varioloid (abortive) cases with no deaths; 21 cases variola with 4 deaths, case fatality 19 percent; 5 cases variola hemorrhagica pustulosum, 3 deaths, case fatality 60 percent; and 8 cases of purpura variolosa with 7 deaths, case fatality 87.5 percent.

The most enlightening and instructive feature of the Korean experience is the matter of protective immunization in all its aspects. As was indicated earlier in the discussion, the incidence of smallpox among the troops was considerably less than 1 case per 1,000 men. These 37 cases, however, occurred among individuals presumably immune. Why were they not immune? According to their records, nearly all had been vaccinated within a year. Some had lead several vaccinations, but only 5 of the 35 whose records were available had been successfully vaccinated prior to entry into the Army. Nine gave a history of attempted vaccination with no take. The other 21 had not been vaccinated as civilians. Of the 35, 30 had records, confirmed by direct questioning, of reactions to vaccine ranging in interpretation from vaccinia to immune type after induction into the Army. The remaining five had records indicating immune-type reactions but stated that there lead been no reaction.

As a part of an investigation planned by the Preventive Medicine Service, Office of the Surgeon General, Dr. William G. Workman of the National Institutes of Health, United States Public Health Service,, visited Korea at the request of the Commanding General, United States Army Forces in Korea. Dr. Workman arrived in January 1946. He believed that failure of previous vaccinations to protect troops was due to the use of vaccine which had been allowed to deteriorate by failure to keep it at temperatures below 0o C. in all phases of transport and storage and that United States vaccine was as effective as any special vaccine made on such animals as camels or caribou.

Craigie and Wishart 24 have produced the immune type of reaction both with heat-killed vaccine lymph and, more significantly, with carefully washed formalin-killed elementary bodies of vaccinia on persons who had at some time in the past been vaccinated. No reaction occurred when this killed virus material was applied to persons who had never been vaccinated.

23 Hampton. B. C.: Smallpox in Relation to State Vaccination Laws and Regulations.Pub. Health Rep. 58: 1771-1778, 3 Dec. 1943.

24 Craigle, J., and Wishart, F. O.: Skin Sensitivity to Elementary Bodies of Vaccinia. Canad. Pub. Health J. 24: 72-78, February 1933.


Wolpe 25 in a South African study demonstrated the value of repeated attempts to vaccinate.In his study, he revaccinated all those who did not show a reaction progressing at least to vesiculation. That is to say, he revaccinated not only "no take" individuals but also those whose reaction would normally be called "immune." The initial Vaccination of one group resulted in 67 percent positive reactions according to his criteria. They were examined after 4 days. The remainder were again vaccinated, and 41 percent (Nearly 14 percent of the total) lead takes progressing at least to vesiculation. Those still not reacting or producing less than vesiculation were vaccinated a third time, and 11 percent (2 percent of the total) developed reactions of vesiculation or better. Eighteen percent still showed no demonstrable positive (vesiculation) when read at 4 days. By revaccination, he had raised the percentage giving a reaction beyond the type usually designated as immune in from 67 percent to 82 percent.

This would indicate that in vaccination programs in such organizations as all armed force, initial vaccinations should be done, not at the time of induction, when the individual is in every sense a transient, but at the training camp at which the individual will first be under the close supervision of the same medical officer for at least 10 days. This is necessary to insure that the results of vaccination are properly observed and that ail accurate descriptive entry is made in the individual's record of immunizations. Of greater importance, the individual must be revaccinated until a vesicular reaction or primary-type reaction takes place, or until three attempts with known potent vaccine and proper technique have been made.

Entries in immunization registers should use descriptive terms such as "papular," "vesicular," and "pustular," rather than terms such as "immune," and "vaccinoid." The length of time intervening between the application of the vaccine and the height of the reaction should be included in the descriptive record.


Smallpox among civilian populations presents a threat to troops operating or residing in the same area, disrupts the civilian economy, and, in the case of United States Armed Forces, always presents the humanitarian responsibility of doing something for the population under military control. The experience of this great global upheaval needs analysis in order to predict the behavior of smallpox ill another world conflict.

In 1947, the author gathered information on the incidence of and number of deaths from smallpox i11 various countries of the world during the war years in order to see if any pattern existed. Recently a more complete com-

25 Wolpe, J.: Report of 3,052 Vaccinations With Special Reference to Value of Repeated Attempts. South African M. J. 19: 339-340, 22 Sept. 1945.

26 (1) Stuart, G.: Note on the `Immunity Reaction' Following Vaccination Against Smallpox. Bull. World Health Organ. 1: 30-31, 1947-48. (2) MacKenzie, M.: Significance of the `Immunity Reaction' Following Vaccination Against Smallpox. Bull. World Health Organ. 1: 32, 1947-48. (3) McKinnon, N. E., and Defries, R. D.: Interpretation of Reactions Following Revaccination. Canad. Pub. Health J. 22: 33-39, January 1931.


pilation of smallpox statistics has been published in the Chronicle of the World Health Organization. 27 Certain patterns of behavior present themselves.

While no great pandemic arose among the civilian populations during or after World War II, as used to follow most other wars throughout history, World War II nevertheless brought about directly or indirectly a great recrudescence of smallpox in many areas of both hemispheres.

The various countries of the world fall rather easily into three groups: (1) Those which have efficient, rigorously prosecuted vaccination programs; (2) those in which classical smallpox is endemic, control measures being exer cised only sporadically to halt or limit periodic outbreaks in various communities; and (3) those (the largest group) wherein classical smallpox is not endemic but in which vaccination programs are lax and are pursued on an inefficient level. In the last group, the vaccination programs may be marshaled in full force whenever imported classical smallpox causes an outbreak but, on the other hand, are only mildly stimulated by the regular presence of alastrim at a low morbidity and mortality level. The main protection of this third group is the immunizing presence of alastrim, a tendency for a rather high rate of vaccination of infants on a voluntary basis, and, in some, an ability to do a prodigious amount of vaccination when classical smallpox appears.

Sweden and Switzerland fall into the group characterized by complete, efficient control. As nearly as could be determined, no deaths occurred from 1936 to 1946, inclusive. Cases are recorded only occasionally, and these probably represent importations. While these two neutral countries were immediately adjacent to the turmoil of war, they are relatively remote from any endemic area of classical smallpox.

India and Mexico represent the endemic group wherein explosive outbreaks of disease may be expected at 5-year to 10-year intervals.28 The mortality peaks demonstrated for India and Mexico during the war years are exceeded by peaks occurring in 1936 and could have been expected, war or no war.

The third and largest group contains all gradations between the extremes of complete control and endemicity with little control. Among this group showing a marked rise in smallpox during or immediately after the war years, which probably was the result of disturbance of controls and movement of peoples incident to the war, are Egypt, Turkey, Japan, Korea, and to a lesser extent the United States and Great Britain. The deaths in the United States arose largely from one outbreak of classical smallpox (1946), which occurred because of importation into Seattle, Wash., from the Orient. Although quickly suppressed by mass vaccination, it cost 20 lives.29

Italy was fortunate, for although an epidemic of smallpox arose through importations from North Africa, it was the mild alastrim and carried a negligible mortality.30 No direct connection between the imported case and the first

27(1) World Prevalence of Smallpox During and After the Second World War. Chron. World Health Organ. 2 (12): 278-281, December 1948. (2) See footnote 7, p. 152.

28See footnote 2, p. 152.

29 Palmquist, E. E.: The 1946 Smallpox Experience in Seattle. Canad. J. Pub. Health 38- 213-218, May 1947.

30 Stowman, K.: Smallpox at Bay and at Large. Epidemiol. Inform. Bull. 1: 371-376,15 June 1945


local case could be demonstrated, though both patients were in separate rooms on the same isolation ward for a short time. The local patient was vaccinated at this time, and a simultaneous incubation of variola and vaccinia which occurred led to an initial erroneous diagnosis of generalized vaccinia. The patient was not isolated, nor was a program of vaccination of contacts carried out for 3 days; thus the initial spread of the disease within the city was permitted.

Canada has controlled smallpox well and appears not to have suffered an importation of virulent smallpox during the period.

Uruguay, a neutral, remote from the, combat areas, nonendemic, and with a fairly effective program of control, developed a definite increase in reported cases, and in 1947 a localized outbreak of smallpox carrying a considerable mortality occurred.

Two countries (Sweden and Switzerland) have controlled smallpox to an amazing degree of completeness. Endemic areas seem to have their periodic epidemics without reference to events in other parts of the world and are affected only slightly (in timing and intensity) by internal events. Countries whose programs and conditions fall between these two extremes are subject to great fluctuations directly related to catastrophes (such as war) which increase importations of virulent forms of the disease and, depending on the distance from the catastrophic area, disrupt the incomplete and often very inefficient programs of control.

It may then be expected that, as the result of any such great disturbance, global war, for example, any nonendemic country not having prosecuted a complete, thorough program of control for a considerable period of time may experience an unusual incidence of smallpox which may reach proportions of a major epidemic, whether that country be combatant or neutral, and whether it is located near to or remote from the centers of disturbance.