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A pandemic appearance of influenza A virus must be expected at any time. The limitations of health preserving and life-saving resources, which will inevitably be reached in the event of a pandemic, will be accompanied by ethical and possibly social conflicts, which can be lessened or resolved only through precautionary planning, clearly specified competencies and transparent decisions within a social consensus. In case of a shortage of vaccines and virostatic agents, decisions will have to be made with regard to the segment of the population that absolutely must be vaccinated. It is currently estimated that a (monovalent) vaccine developed for a new pandemic strain would only suffice for the single vaccination of approximately half of the German population after a year; only 10-14 million vaccine dosages would be available to provide basic immunization and single boosters to personnel required to maintain basic medical care and essential infrastructure after half a year. In the event of local influenza outbreaks, antiviral chemotherapeutic agents could be used to close the gap until a vaccine can become effective. Even if suitable influenza vaccines and virostatic agents are not sufficiently available at the start of a pandemic, it is still possible to at least prevent an outbreak of two of the most feared secondary infections that accompany influenza: pneumococcal pneumonia or meningitis and illnesses resulting from Haemophilus influenzae. Agreement still needs to be reached with manufacturers for guaranteeing the necessary vaccine production or ensuring that they have a sufficient stock to meet the minimum demand for antiviral agents and agents for symptomatic treatment.

The following conceptual framework formed the basis for a common decision made by the health ministers of Germany's 16 federal states to set up an influenza pandemic preparedness plan. The worst case scenario was used, on the basis of the data from the pandemic of 'Spanish flu', in 1918-20. The priority groups for vaccination were assessed, as well as the potentially available antiviral treatments. National policies could be highly improved by a common European view.

360 volunteers were recruited for the investigation from a homologous collective. 174 were immunized parenterally with "Influmun" from SSW Dresden, GDR. 176 volunteers were immunized twice orally with an interval of 60 days with an influenza vaccine inactivated by x-ray using enteric-coated capsules. In an interval of six months ARI-symptoms were investigated. Between 13th and 17th week 1988 an increased ARI-morbidity in the Greifswald-region was observed in which influenza A viruses were involved. In comparison with 312 non-immunized persons of the same age, sex and living area the immunized volunteers of the two groups showed 83.4% less sickness days. 30 persons of the non-immunized group got ill for totally 217 days, whereas only nine persons of the two immunized groups were put on the sicklist for totally 36 days. No significant differences concerning the occurrence and duration of acute respiratory infections (ARI) between the two differently immunized groups could be observed.

In a multicentric trial 350 persons (19-24 years) were immunized with influenza vaccines containing the following virus antigens: A/Singapore/6/86, (H1N1); A/Mississippi/1/85, (H3N2); B/Ann Arbor/1/86. 174 received an i.m. injection of 0.5 ml "Influmun" vaccine from SSW Dresden/GDR. 176 persons were immunized twice within 60 days with enteric-wated capsules each containing approximately 60 micrograms hemagglutinin of all three virus strains. The volunteers were clinically observed in an interval of 6 months. The majority of orally immunized persons with low pre-immunization titers responded with fourfold or higher IgA antibody titer rises in nasal secretions, but no significant IgG antibody titer increase in sera could be observed. Secretory antibody titers remained elevated for 2 to 4 months. Parenterally immunized persons showed antibody titer rises in sera but not in nasal secretions. In both groups the highest antibody titer increases were observed after application of the A/Singapore/6/86 virus antigen. Volunteers with high pre-immunization titer did not show an antibody increase neither after parenteral nor oral immunization.