Measles Prophylaxis

MEASLES PROPHYLAXIS, the introduction for preventive purposes into children who have not had measles of serum from measles convalescents. Such serum, when administered to a child threatened with infection or already infected, with great regularity protects against measles. If the disease does occur, it is usually of a mild, abortive character. For the first time, this serum was successfully used prophylactically in 1916 in Tunisia by Nicolle and Conseil (Nicolle, Conseil). Similar observations were made in 1919 by Americans Richardson and Connor (Richardson, Connor) and in 1920 in South America by Torres and Pacheco (Torres, Pacheco). The methodology was developed in detail by D. in 1920. - Blood is taken from healthy, robust children over three years of age who have had uncomplicated measles, on the 7th-9th day after the temperature has subsided. From a child under 5 years, 20-50 cm³ can be obtained, from older children 60-100, from adults 150-200. Any suspicion of syphilis, tuberculosis, malaria, and other diseases must be excluded by careful collection of anamnesis and clinical examination. Blood is taken with a well-sharpened Wassermann needle from the cubital vein with strict observance of aseptic technique. The blood taken for clotting is placed in an icebox for 1-2 days, after which the serum is aspirated and inactivated in a water bath for 1 hour at 58°. Serum obtained from several subjects is pooled together, and after adding phenol (to obtain a 0.25% solution) or chloroform (to obtain 0.5-1%), it is poured into glass ampoules. In sealed ampoules, the serum can be stored in a dark, cool place (in an icebox) for 3 months. Bacteriological control of the serum should be performed after aspiration, at the beginning of pouring, and at the end of pouring. To smooth out individual characteristics of sera, it is necessary to mix sera from 3 or more children. D.'s own method somewhat differs from the one described. D. adds 1 drop of a 5% solution of carbolic acid to 40 cm³ of serum and pours it into wide-mouthed flasks of 5 and 3 cm³ capacity. The flasks plugged with cotton are subjected to drying in a vacuum desiccator over anhydrous calcium chloride and sulfuric acid. Before use, the dry serum is dissolved in 5 cm³ of sterile water. This preparation method gives a preparation of unlimited stability, convenient for shipping, but on the other hand requires mandatory testing of each donor's serum by the Wassermann reaction, which becomes unnecessary with the above-described method, since the one-hour heating at 58° and subsequent addition of an antiseptic definitely sterilizes the serum. The serum is administered intramuscularly or subcutaneously. The vaccinations themselves are harmless. If complications occur during them, they are caused by violations in the preparation technique of the sera or in the technique of administering the vaccinations. - For dosing, three factors are considered: the age of the vaccinated person, their physical condition, and the time of infection. In connection with this, D. proposes the following dosage scheme. Physical condition of the child Age of the child Dosage of serum on the 3rd day on the 5-8th day on the 7-8th day Healthy, robust children . . . . Sick children, especially cachectic children 1-4 years. Over 5 years. 1-4 years. Over 5 years. 5 cm³ 6 cm³ 8 cm³ 9 cm³ 6 cm³ 9 cm³ 9 cm³12 cm³ 9 cm³ D. considers 3 cm³ of serum as the protective unit. This dose, administered to a healthy, robust child under 5 years of age during the first 4 days of the measles incubation period, protects against the disease. For older children, weakened children, and when administered at later times, the serum dose is increased. Observations conducted by Danilevich in 2,000 cases lead to the conclusion that it is necessary to increase the basic unit from 3 to 5 cm³. The difference in dosage may be connected with the preparation method. D. does not inactivate the serum; in the USSR it is inactivated. When an insufficient dose is administered or at late incubation periods (on the 7th-9th day), the disease may occur, but in such cases it more often runs a mild, abortive course. D. believes that administration on the 8th day and later, even with massive doses-up to 30 cm³-is unsuccessful, but a number of authors observed a positive effect even at these late periods. Due to the difficulty of obtaining convalescent measles serum, its use should be as rational as possible. First of all, serum must be administered to children of the age that suffers the greatest losses from measles, i.e., children of the first 3 years, then children burdened with pathological conditions, those in children's institutions, patients, and those in poor home conditions. In some cases, the task of prevention comes down to preventing the disease, in others, on the contrary, to inducing abortive forms. D. distinguishes between passive immunization and so-called combined immunization. Purely passive immunization occurs in cases where vaccination is done before the infection occurs. The duration of immunity in this case averages 2-4 weeks. - Combined, or active-passive immunization is obtained by introducing serum into an already infected organism. In these cases, even with complete prevention of the disease, the body independently produces antibodies, resulting in a longer immunity, which D. calculates as 9 months. Serum from such cases has protective properties against measles. The second subtype of combined immunization includes cases where there is not prevention of the disease, but the presence of an abortive form of measles. A child who has had such an abortive measles acquires a long-lasting, possibly lifelong, immunity. These forms are contagious, although the period of contaguity, due to the ephemeral nature of the disease, lasts for a short time. Purely passive immunization is used in children entering children's institutions where measles cases have occurred. More often, more precisely-as a rule, vaccinations are done after infection. It is more rational to aim not at preventing the disease, but at obtaining abortive forms, which provide lifelong protection against measles. Complete prevention of the disease must be sought in hospitals in order to combat hospital infections and in very weak, sickly children. Properly performed vaccinations lead to the desired positive results. Failures average 3% (Degkwitz, Torday) and are caused by incorrect calculation of incubation days, deviation from established methods, and in individual cases depend on the random selection of low-activity sera or on individual properties of the vaccinated person. The lack of convalescent measles serum is tried to be compensated by using adult serum. The protective value of adult serum is firmly established by D. and a number of other authors (Salomon, Gerlach, Torday, Kutter, Danilevich and Kolchanova, etc.). Adult serum is especially valuable when it is necessary to obtain abortive forms of measles. Failures in terms of absolute prevention of the disease occur in a higher percentage of cases compared to convalescent serum. D. calculates 1 prophylactic unit as 30 cm³; Debre (Debre) in quantities 4 times greater than those established for convalescent serum. According to Danilevich's data, 50-60 cm³, administered to a child under 5 years on the 5th-6th day of incubation, as a rule protect against the disease. In the absence of serum, blood citrate is used. To prevent rapid clotting of blood, 1 cm³ of a 5% sterile solution of Natrii citrici is added to 10 cm³ of blood in the syringe. After taking the blood, it is immediately injected into the child. Citrate is administered in 2-3 times larger quantities compared to adult serum. Whole blood can only be administered from parents after thorough examination to exclude tuberculosis, syphilis, malaria, and other infectious diseases. Attempts have been made to use for the prevention of measles also serum obtained from umbilical cord blood. Obtaining such serum is associated with great difficulties. Since the blood must flow by gravity, only 15-20 cm³ can be obtained from one case. This method has not received practical value. Negative results were also obtained in attempts to replace convalescent measles serum with human milk, non-specific proteins, and animal immune sera. Convalescent measles serum and adult serum are widely used in all countries, especially in France and Germany. In Munich alone, an organization at the university children's clinic supplies about 2,000 units of serum annually to institutions and private individuals. In the USSR, D.'s vaccinations are used in a number of cities. In some of them, there are permanent organizations for the procurement and distribution of serum (in Leningrad, Moscow, etc.).

In hospitals and in some children's institutions in Leningrad, with systematic and consistent use of the method of D., it is possible to reduce mortality from hospital-acquired measles to extremely small figures (Danilevich, Dobrokhotova, Kanevskaya, Skrotsky). Such successes bring us closer to resolving the formidable problem of nosocomial diseases. At the present moment, it is time to use the method of D. also in the home setting with the help of consultations, outpatient clinics, dispensaries, and mainly through the institute of home care physicians. Such work will not only lead to the preservation of children's lives but will also be beneficial from a material point of view due to reduced demand for children's hospital beds. The experience of both other countries and the USSR leads to the necessity, in order to carry out absolutely impeccable bacteriological control and the most rational expenditure and accounting of the action of sera, to centralize all work on anti-measle vaccinations at bacteriological institutes. As donors can be used: 1) measles convalescents in hospitals, in children's institutions and, if possible, in families, including in this group persons who have had measles in the last 2-3 years, 2) parents of children admitted to children's hospitals and children's institutions of younger age, and 3) paid volunteers.