Vaccinia and Vaccination.
Synonym:—Cowpox.
Definition:—Vaccinia is a mild eruptive disease occurring originally in heifers and cows and characterized by an eruption upon the teats and udders. It is induced in mankind by inoculation with the serum from a cow pock, for the purpose of producing the immunity from smallpox which the bovine disease confers. This inoculation is called vaccination.
Direct inoculation from a smallpox pustule has been practiced in China for centuries, and was introduced into England and quite extensively adopted for many years prior to the discovery of the immunizing power of the vaccinia vesicle which was discovered by Jenner in 1778 and announced to the world in 1798.
Vaccination is now made obligatory by nearly all the civil governments of the world. The results of the method, in almost annihilating smallpox as an epidemic disease, have proven that successful vaccination and revaccination will confer complete immunity against variola. A feeble opposition is still made against its practice by those who do not take a comprehensive view of the field. They enforce their argument by the fact that an occasional case is infected from careless methods or from the use of impure virus.
Vaccine virus is of two kinds, the bovine and humanized. The first is obtained from the pock on the udder of an infected cow, and the second is obtained from a typical vaccinia vesicle from a person who has been originally inoculated from a cow pock. The virus is obtained from the liquid contained in the vesicle. The disease is now propagated on farms for the purpose of furnishing the virus in a strictly pure form. Small ivory points are dipped in the virus and are then dried and preserved aseptically, retaining their virtue for from ten days to two weeks. It is also dissolved in glycerine and preserved in sealed capillary tubes.
The Method of Vaccination:—A point is selected, usually upon the left arm or thigh, which is rendered thoroughly aseptic. A small circumscribed area should then be so carefully denuded of the skin as not to draw blood. This is best done by an instrument with square end or point, but may be done with a lancet. A scarifier usually draws too much blood. If a drop of ammonia be confined on the skin for a few moments or a strong solution of potassium hydrate, the skin is readily removed with no pain, and the virus may be applied to the denuded surface by rubbing the charged end of a point which has been moistened by dipping in water, carefully but firmly over the denuded surface, or a capillary tube is broken and its contents spread over the denuded surface. The spot should be exposed to the air until it is dry.
A child should be first vaccinated at about the age of two years, unless smallpox is present with danger of exposure, and again every five, six or seven years. If exposed to smallpox, immediate re-vaccination should always be practiced. An infant may, upon danger of exposure, be vaccinated at birth, and a pregnant woman, if exposed, should be vaccinated or re-vaccinated at once. This protects both herself and the unborn child.
Symptoms of Vaccinia:—The period of incubation after the inoculation is about five days. On the third day at the seat of the vaccination a small papule appears, with a red areola. In three days more this becomes a vesicle filled with colorless lymph, and is umbilicated. This is tender, painful and itches. From the fifth to the tenth day constitutional symptoms develop with most of the patients. There is malaise, a slight chilliness and fever. On the following day, in severe cases, a rose-colored rash (roseola vaccinosa) develops over the surface of the body. By the tenth day the vesicle has become a pustule with a considerable degree of local inflammation, and the axillary or inguinal glands become enlarged and sore. From this period the local inflammation subsides, the constitutional symptoms abate, the pustule becomes desiccated, a brown scab will form, which becomes harder, and by the eighteenth or twenty-first day will fall off and leave a permanent characteristic scar, which is typical of the disease if not modified by local treatment.
In infected cases the evidences of direct pus infection are very pronounced. The pustule becomes greatly enlarged and violently inflamed, and the constitutional symptoms are severe. There is a pronounced high temperature, and sloughing may occur with circumscribed gangrene. Erysipelas is a not uncommon complication, and patients suffering from that illness must not be vaccinated until they have recovered.
Treatment:—No remedies specific to the disease as a whole are considered. In the severer cases the symptomatic indications as they appear should be met with the indicated remedies, although usually no treatment is prescribed. Aconite, sarracenia, baptisia, phytolacca, echinacea and calcium sulphide are most frequently demanded. Where there is marked septic infection the tincture of the chlorid of iron should not be neglected for newer and less active remedies. The vesicle should be protected from the first by gauze or by a shield. In the latter stage an ointment is demanded with strict asepsis. If the vesicle, after the fifth or sixth day, is treated with echinacea locally and covered with a stiff ointment of bismuth subnitrate and lanolin, it may heal up with but little scar.
Complications must be anticipated and promptly met with direct energetic treatment in accordance with their indications.
