If it be admitted that influenza is spread solely through discharges
from the noses and throats of infected persons finding their way into
the noses and throats of other persons susceptible to the disease, then
no matter what the causative organism or virus may ultimately be
determined to be, preventive action logically follows the principles
named below and, therefore, it is not necessary to wait for the
discovery of the specific micro-organism or virus before taking such
action.
I. Break the channels of communication by which the infective agent
passes from one person to another.
II. Render persons exposed to infection immune, or at least more
resistant, by the use of vaccines.
III. Increase the natural resistance of persons exposed to the
disease, by augmented healthfulness.
_I. Breaking the channels of communication._
(a) By preventing droplet infection. The evidence offered indicates
that this is of prime importance.
(b) By sputum control. The evidence offered indicates that the danger
here is due chiefly to contamination of the hands and common eating
and drinking utensils.
(c) By supervision of food and drink. Evidence offered does not
indicate much danger of infection through these channels.
Details and practical methods possible for the limitation of infection
through droplets, sputum, and food and drink are discussed later under
special preventive methods.
_II. Immunization and vaccines._
(See the report of the laboratory committee appended.)
In the present epidemic vaccines have been used to accomplish: