A Practical Treatise on Smallpox

by George Henry Fox

In the method by puncture either a grooved lancet or a hollow needle may be used. A shallow puncture is made and the virus is deposited in it. The resulting vesicle is usually small and nearly circular, and generally remains free from infection; but as the hole in which the virus is placed is small, it is possible that the issuing blood may wash it away completely, and the percentage of success with this method of inoculation is not quite so large, even in careful hands, as by the process of scarification with the same virus. Animal experiments with deep injection of virus through a hypodermic syringe and with administration of virus by the mouth show that there is no certainty of successful vaccination by these means, and that when success results there is no proof of it without a subsequent vaccination on the skin to test or to demonstrate the immunity.

Care after Vaccination.—As vaccination is a surgical procedure, it should be conducted aseptically with a sterile instrument on clean skin, and the wound should be guarded against extraneous infection. It is well therefore to put either a sterile gauze cover or a clean shield over the wound as soon as the virus has been sufficiently absorbed, and to leave the protection on until the natural crust has been formed,—i.e., for a few hours. If the guard could be kept in position without motion and also without injurious pressure, it might remain until the process ended with the formation of a scar and the exfoliation of the crust; but practically it is so certain that the guard will be moved that it is wise to remove it and to trust to the protection of a clean muslin or linen cloth attached to the loose sleeve or other undergarment. For a day or two at the time when the inflammation is at its height it may be well again to guard by a shield against injury from a blow or push, but the shield should always be regarded as itself a danger. If by any accident the vaccine pustule becomes infected, it should be treated like any other infected wound,—the crust removed, the ulcer cleansed with antiseptics and dressed surgically. The immunity given by the pock is not at all lessened by this treatment.

Normal Clinical Course.—After primary vaccination in man there is a stage of incubation lasting for from forty-eight to seventy-two hours; a papule then develops, and by the end of the third or fourth day this has begun to show umbilication and a vesicular structure. When fully developed, about the sixth day after vaccination, the vesicle is distended and pearly in color. On the seventh or eighth day the areola develops,—i.e., the skin about the vesicle becomes hard, sensitive, and red, the redness extending a variable distance, not usually more than two inches from the edge of the vesicle. In the course of the next day or two the vesicle loses its pearly appearance and becomes opaque and often slightly yellow. With the development of the areola and of the pustule the adjacent lymph glands may swell and become somewhat painful; there may also be constitutional derangement,—some fever, pain, anorexia, restlessness, and more or less prostration; there is usually a moderate leucocytosis. About the eleventh or twelfth day the areola begins to fade, the constitutional symptoms to subside, and the pustule to dry up. A dark crust is formed which drops off usually between the eighteenth and twenty-fifth days, leaving a rosy depressed scar on which not infrequently a secondary scab is formed, to be shed a few days later.

Variations in the Clinical Course.—The vesicles may appear on the second day, but it is more frequently delayed until the fourth, fifth, sixth, seventh, or even the eighth day, and cases have been observed in which the delay was even longer.

The areola, which should be bright red, may be purple, and may extend a long distance from the vesicle.

The pustule may be hemorrhagic or may be filled with greenish pus; in this case there is probably a mixed infection.

Sometimes instead of a vesicle there appears a hard elevated nodule, in color like a red raspberry. With this there is usually no areola, and no constitutional symptoms develop. The growth is usually an evidence of poor virus. It may persist for some time before absorption.

The course may be abortive,—i.e., the vesicle does not develop completely; pustulation comes early and the crust is shed and the scar formed before the end of the second week. This course is normal though not invariable in revaccinations.

The scar may be poorly marked, even when the vaccination has run a typical course.

Complications.—The most frequent complications are infections and eruptions. An infection may be, of course, of many sorts. It may be, for example, the streptococcus of erysipelas, or the bacillus of tetanus, but it is oftenest a skin coccus. These infections may be introduced with the virus, with the instrument, or later through wounds in the vesicle or pustule. Erysipelas and tetanus following vaccination are exceedingly rare, and it has never been shown that in a case of tetanus the germ was inoculated at the time of vaccination.