Search

Ten strains of influenza B virus isolated in a local focus during an influenza outbreak were found to include 9 virus strain variants as demonstrated by different antigenicity of their haemagglutinin, ts-marker, sensitivity to heating at 56 degrees C/30 min, and to non-specific serum inhibitors. These strains induced antibodies in rats which interacted more actively with the virus isolated in earlier periods of this outbreak than with that isolated later. It might indicate that all strains originated from the same parent strain of virus, which induced the influenza outbreak in this area.

Examinations of ARD patients in an orphanage for defective children in Moscow during an influenza outbreak in the winter of 1988 yielded 12 influenza virus strains, including 6 influenza B strains and 6 influenza A (H3N2) strains. The antigenic analysis of hemagglutinin of influenza B virus isolates showed that with respect to the B/Leningrad/179/86 strain (an antigenic analogue of B/Ann Arbor/1/86 strain recommended for inclusion into the influenza vaccine for 1987-1988) they could be divided into 2 groups: antigenically close to the B/Leningrad/86 strain (isolate B/712) and markedly differing from it (the remaining isolates). As compared with reference strains of the previous years, all the new virus isolates fell into 4 groups: isolate B/712 antigenically related to B/Hong Kong/73 and B/Leningrad/86 strains; B/722 antigenically close to B/Singapore/222/79 and B/USSR/100/83 strains; B/724, an antigenic analogue to B/USSR/100/83; and the remaining isolates, to some or other extent, differing from various reference strains. This attests to simultaneous circulation of various antigenic variants of influenza B virus during the 1988 winter outbreak of influenza in Moscow. An interesting feature of the B/712/88 isolate consists in its antigenic specificity of hemagglutinin being indistinguishable from that of B/Hong Kong/8/73 strains.

During the autumn-winter epidemic of influenza-like diseases in December, 1983--first quarter, 1984, in Moscow commissioned coded observations on the effectiveness of prophylactic vaccination against influenza of 3-7-year-old children with a preparation "Grippovak SE-AZh" were carried out in day-care centers. In the previous large-scale trials, 1981-1984, the "Grippovak" had been evaluated positively as a completely harmless, serologically and immunologically active preparation reducing 3-3.5-fold the number of laboratory-verified cases of viral type A and B influenza in the vaccinees. In 1986, however, the "Journal of Microbiology, Epidemiology, Immunology" (JMEI, 2: 49-54) published a paper whose authors, on behalf of the Commission which had checked the preparation in the day-care centers (Z.A. Bashliaeva, A.A. Sumarokov, et al.), came to a conclusion that "Grippovak" was ineffective in children. Other members of the above Commission disagreeing with this conclusion made a repeat analysis of the decoded materials of the observations in the day-care centers using computer methods and demonstrated that because of significant prevalence of non-influenza ARD cases and recurrent (up to 44%) ARD cases in children in the 4 months of observation, it was impossible to judge the effectiveness of the vaccine by comparison of the total incidence of influenza and ARD from the clinical data alone in the vaccinees and controls.(ABSTRACT TRUNCATED AT 250 WORDS)