PREVENTION OF DIPHTHERIA

Efforts to prevent diphtheria take two main directions. In one the object is to prevent the infection of new persons; in the other the measures employed are used to render well persons immune to the disease so that they will not become sick even if the germs reach them. Prevention of the infection of other persons is accomplished by isolation or quarantine of the sick individual and his attendant. To be effective quarantine must be carried out with conscientious attention to the smallest details. When a member of a family develops diphtheria, other members of the household may permanently leave the house if they are free of diphtheria germs as shown by cultures. The way in which quarantine is carried on has been described as it relates to all the diseases under discussion. In the case of diphtheria quarantine can only be terminated when repeated cultures from the throat and nose have shown that the diphtheria bacilli have disappeared. This may require several weeks and in exceptional cases even months. Carriers must be placed in quarantine as well as active cases. As recovery from diphtheria progresses the germs tend to die out and often are no longer present after a few days. Sometimes the germs persist and the patient becomes a persistent carrier. In the persistent carrier usually some abnormal condition in the nose and throat interferes with the efforts of nature to destroy the germs. When such are corrected the germs often quickly disappear. Most often diseased adenoids and tonsils are the offending conditions. In this case the removal of abnormal adenoids and tonsils is usually followed by prompt disappearance of the germs. Persistence of bacilli in the nose of children has sometimes been dependent on the presence of foreign bodies such as shoe buttons.

Aside from the measures outlined which have for their purpose the prevention of extension of the germs to other persons, important steps may be taken to render persons immune to diphtheria so that they will not be affected by the germs. This is accomplished in two ways. In the presence of immediate danger, small doses of antitoxin at intervals of three to four weeks procure protection. This is to be selected when children in a family cannot be protected from infection by quarantine. When immediate danger is absent an immunity which lasts for years may be secured by a sort of vaccination. This consists of three hypodermic injections at intervals of a week of a mixture of diphtheria toxin and antitoxin. The amount injected is very small and produces little or no inconvenience, but it is followed in a few weeks by a lasting protection against future infections. Almost all persons become immune after such injections. Such vaccinations have been used in a large scale among school children in New York City. Among 90,000 school children thus treated only one-fourth as many cases of diphtheria occurred last year as among the same number who refused the treatment. Injections are advised in children as early as possible after six months of age is reached. If this were uniformly employed children would be protected against diphtheria during the most susceptible years, and the disease would largely disappear. It is not too much to hope that this vaccination measure against this most fatal disease of children will accomplish corresponding favorable results to those which have followed vaccination against small pox.

It is not desirable or necessary to use such injections in children who are already immune. By a simple harmless test it is possible to determine if susceptibility exists in the individual. This is known as the Schick test. It is easily given and is devoid of all danger and discomfort. Such tests have shown that the proportion of persons susceptible to diphtheria varies with age. Few infants under six months are susceptible. From one to three years about 60 per cent are susceptible. As age advances the proportion gradually decreases so that by 20 years only about 20 per cent are liable to be infected if opportunity occurs. The children in the families of the well-to-do are susceptible in larger proportions than are those living in crowded parts of cities, and in country districts the proportion of susceptible children is very high.