Summary: The most universally employed measurement of the impact of epidemics and pandemics is the excess of mortality due to influenza and pneumonia. Other criteria are absenteeism from school and work, and all three will show positive indications when epidemics are of substantial size. During the 1974–1975 influenza season in Houston, school and industrial absenteeism and the increase in influenza and pneumonia deaths, despite a newly devised statistical procedure, did not signal an epidemic. However, a system of community surveillance of febrile respiratory illness with cultures for influenza virus during late January and early February 1975 gave unmistakable evidence of an influenza epidemic, with more than 600 virus isolations and an estimated occurrence of 50,000 cases of the disease. It is believed that this type of study can explore facets of the epidemiology of the disease not hitherto adequately examined. From this surveillance, which will continue through the summer months, it is hoped to gain further knowledge of the occurrence of antigenic drift and shift, and of the details of the early origin and progress of epidemics.Current speculation is that there will be another world pandemic before 1980 caused by a derivative of A strains presently circulating; in 1985–1991, a pandemic is predicted to be caused by a virus, antigenically related to the swine agent of 1918.The purity of vaccines has been increased in recent years through ultracentrifugation and high-efficiency filtration, so that dosages can be increased while severity of reactions is reduced. The current level of dosage of vaccine for adults is 1200 chick cell agglutinating units, almost double what it was a dozen years ago. Recently, vaccines have been prepared more rapidly by the use of viral recombinants that incorporate the surface antigens of newly emerged epidemic strains into the core of older strains that grow well in embryonated eggs. This practical device greatly reduces the lead time in the preparation of new vaccines.The main problem in immunization against influenza is the need to reimmunize every 1–3 years. This creates an enormous requirement for vaccine and therefore a problem of selection of recipients. Currently, it is recommended that aged persons and those with cardiovascular, pulmonary and other chronic illnesses should receive the vaccine. Pregnant women are not more susceptible than others to the disease, and they should receive vaccine only if they have some other indications for immunization. Schoolchildren probably are important in transmission of the disease, but at present there is no special recommendation to immunize them. Young children occasionally have severe febrile convulsions when immunized against influenza, and those with this history probably should not be immunized.Amantadine is useful as a prophylactic agent in A(H3N2) influenza infections, and several reports suggest therapeutic benefits as well. Its benefits probably have not been fully utilized. Studies with larger doses should be made in the treatment of influenzal pneumonia. In experimental influenza A infections in mice, amantadine and some other agents were remarkably successful when given as continuous small-particle aerosol from the third to the seventh day. The possibility of aerosol treatment of influenzal pneumonia in man should be examined.Evidence was presented that influenza epidemics were associated with increased leukemia in children. The study was well designed and executed, and the results cannot be easily dismissed despite the fact that some older studies did not show this relationship.Studies of the cell-mediated immunologic system in influenza reveal a suppression during acute illness and sensitization following immunization and/or infection with influenza virus. Skin test studies suggest that sensitization to influenza virus may be very common in the population. Mice adoptively immunized with node and spleen cells from donors that had been vaccinated against influenza had a higher mortality than controls when challenged with the homologous virus; this effect was abolished by exposure of the donor cells to antithymocyte serum. Although these studies suggest involvement of the cell-mediated immunologic system in host response to influenza, it is not clear whether the effect of this involvement will be protective or harmful for the host, or differ under varying conditions.Reye's syndrome is a clinicopathologic complex characterized by mitochondrial lesions in hepatic cells, deficient function of one or two hepatic enzymes of the urea cycle, increase of blood ammonia, and possibly other metabolites, and frequently fatal encephalopathy. It has occurred most often following influenza B and some other virus infections, and only occasionally is described after influenza A infection. Treatment has consisted primarily of measures to reduce intracranial pressure.

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{{Explor lien
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   |étape=   Curation
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   |clé=     ISTEX:1C094CB5968C57EBA294B3CAF0DCCE6F9DEFADA8
   |texte=   Influenza
}}