TOXINS AND ANTITOXINS 265 



2. Two doses of alum precipitated toxoid produce as high an 

 active immunity as three doses of plain toxoid. Since the 

 fine precipitate is the active immunizing agent a technique 

 should be employed that assures its administration. Be- 

 cause of the occurrence of annoying local reactions follow- 

 ing the use of precipitated toxoid the Department of Health 

 is recommending that three doses of plain toxoid be employed 

 instead of the two doses of precipitated toxoid. 



3. The Department recommends that the interval between im- 

 munizing injections be one month. 



4. Experience has shown that a variable proportion of chil- 

 dren successfully immunized at the age of nine months "will 

 be found to have very little immunity at the age of four or 

 five years." To bring up the immunity of such children 

 to a protective titer, a single injection of toxoid is sufficient. 

 It is advised that all children immunized in infancy be given 

 a single injection of toxoid shortly before entering school. 

 This is done routinely in the Department's child health sta- 

 tions ; the Schick test is omitted. Children not previously im- 

 munized are given the full course of injections. 



5. Schick tests are given after an interval of two or three months 

 following the completion of a course of immunizing injec- 

 tions. To avoid errors in interpretation the sites of injection 

 are examined from the fifth to the seventh day. A positive 

 reaction is indicated by a persistence of redness or a bro\vnish 

 discoloration at the spot, 



6. Dosage of plain toxoid (three injections). 



a. For children ages 6 years or less three injections con- 

 sisting of 0.5 c.c, 1.0 c.c, 1.0 c.c. respectively. 



b. For children over 6 years of age three injections con- 

 sisting of 0.25 c.c, 1.0 c.c, and 1.0 c.c respectively. 



When a reaction occurs, the subsequent injection should be 

 either the same or less depending upon the severity of the 

 reaction. If the Schick test remains positive after the three 

 injections of toxoid are giveJi, the series of immunizing 

 injections should be repeated. If the Schick test is still 

 positive the Department feels that further injections are 

 inadvisable. 



