2. The prevention or mitigation of complications recognized as due to
the influenza bacillus or to various strains of streptococci and
pneumococci.
In relation to the use of vaccines for the prevention of influenza, the
evidence which has come to the attention of the committee as to the
success or lack of success of the practice is contradictory and
irreconcilable. In view of the fact that the causative organism is
unknown, there is no scientific basis for the use of any particular
vaccine against the primary disease. If used, any vaccine must be
employed on the chance that it bears a relation to the unknown organism
causing the disease.
The use of vaccines for the complicating infections rests on more
logical grounds, and yet the committee has not sufficient evidence to
indicate that they can be used with any confident assurance of success.
In the use of these vaccines the patient should realize that the
practice is still in a developmental stage.
The committee believes that when vaccines are used experimentally for
the purpose of determining their preventive or curative value, the
following conditions should be complied with:
1. The groups of vaccinated and unvaccinated persons should be the
same in number.
2. The relative susceptibilities of the two groups should be equal, as
measured by age and sex distribution, previous exposure to infection
without development of influenza and a previous history as to recent
attacks of the disease.
3. The degree of exposure in each group should be practically the same
in duration and intensity.
4. The groups should be exposed concurrently during the same stage of
the epidemic curve.