[The possibility of long-term prognosis in influenza A pandemics].

On the basis of the analysis of the most significant influenza A pandemics over the period of 300 years, compared with periodic long-term changes in the climate and the cycles of solar activity, regularities in the manifestation of the biorhythms of the epidemic activity of influenza A virus have been established. The prognosis of pandemics for near and remote future is proposed.

[Effectiveness of live influenza vaccines obtained by strain recombination and passages].

A comparative study of the immunizing activity of strain variants derived from one epidemic influenza virus A/USSR/77 (H1N1) by using different attenuation methods was carried out. Serial passages in chick embryos preserved the biological activity of the virus better than genetic recombination which was manifested by a significant superiority of the passaged virus over the reassortant in the capacity of replicating in the upper respiratory tracts of the vaccinees, of inducing immune responses and creating the protection of the portals of entry of infection. The problem of optimal preservation of biological potentials of influenza virus in the process of attenuation is discussed.

[Results of a study of the effectiveness of simultaneous immunization against influenza with live and inactivated vaccines (1980-1983)].

A comparative evaluation of immunological and epidemiological effectiveness of commercial live and killed vaccine preparations used simultaneously or separately was first carried out in simultaneous field trials of various methods of influenza vaccine prevention in a human population of 10,449 subjects. The advantage of simultaneous immunization was confirmed by immunological parameters and protective effect in the period of influenza A epidemic of 1983. The correlation of immunological and epidemiological effectiveness of influenza vaccines in joint or separate administration is discussed.

[Characteristics of the immunological and protective effect in the simultaneous and separate use of live and killed influenza vaccines].

Simultaneous immunization with inactivated and live influenza vaccines is characterized by a more rapid and intensive formation of local protection and humoral immunity persisting for 5 months at a higher level than after separate administration of inactivated and live vaccines. The live vaccine was found to be the major factor enhancing the immune response and local protection in combined immunization. Administration as components of a live bivaccine of influenza serotype A viruses with a different degree of attenuation was not accompanied by higher reactogenicity but led to a sharp decrease of immunogenic activity that indicated incompatibility of such viruses in a bivaccine.

[Immunological effectiveness of a method for simultaneous immunization against influenza using live and inactivated vaccines].

A significant increase in immunological effectiveness of simultaneous immunization with a killed and live influenza vaccine as compared with separate use of these preparations has been demonstrated. The simultaneous immunization better protected the upper respiratory tracts of the vaccinated volunteers, inhibiting reproduction of the challenge influenza virus with residual virulence. A live vaccine from the "old" influenza A/6/50 (H1N1) was found to produce a protective effect on the current influenza A/1977 (H1N1) virus with residual virulence.

[Changes in the indices of the immunogenic activity of influenza A/Hong Kong virus in the 1969-1980 epidemics].

The study of immunological changes in convalescents after influenza aged 7-12 months and 18-23 years was carried out in the period of circulation of influenza A/Hong Kong virus and its antigenic variants (1969-1980). A continuous decrease of the immunogenic activity of the causative agents of repeated epidemics and the intensity of the acquired immunity in adult convalescents was demonstrated in successive epidemics of influenza A/Hong Kong. This regularity was fully confirmed in groups of 7 - 12-month-old infants without previous exposure to influenza infection who experienced the disease.

[Increase in the effectiveness of anti-influenza immunization by use of a combination of inactivated and live vaccine].

The authors applied a new principle of effective immunization against influenza using a moderately attenuated live vaccine which after 5 passages in developing chick embryos had retained a high reproduction activity in the human upper respiratory tract, while the vaccines were not contagious for their susceptible contacts. The safety of intranasal adminstration of the new vaccine is achieved by giving it to primed subjects previously given oral immunization with the same vaccine or intranasal administration of the standard hyperattenuated vaccine. Since the current inactivated influenza vaccine is the standard hyperattenuated vaccine.

Immunological and epidemiological effectiveness of live poliomyelitis vaccine in the USSR.

In 1959 a total of 1 700 000 children up to 14-18 years old in the Latvian, Byelo-russian, Moldavian and Russian Republics of the USSR were given live poliovirus vaccine prepared from attenuated Sabin strains. The results show that the vaccine is highly effective and quite innocuous.The mean reduction in poliomyelitis incidence in the different republics varied from sixfold to tenfold, and among very young children (the age-group at greatest risk) was as high as 15-fold.