In Canada as a whole, influenza A/Beijing/32/92-like virus was the dominant infecting strain in the 1993-1994 season with reported laboratory diagnoses peaking in January 1994. Vaccination is again urged for all persons in high-risk groups. Antibody induced by vaccination does not persist well from season to season and the emerging A/Shangdong/9/93 (H3N2)-like variant is related to A/Beijing/32/92(H3N2) but is inhibited less by antibodies to that strain. Conditions are also consistent with possible increased influenza B activity this season.
Swine flu (H1N1) reached pandemic proportions in 2009, yet ambivalence was met concerning intentions to be vaccinated. The present investigation determined predictors of perceived H1N1 contraction risk and vaccination intentions among Canadian adults (N = 1,027) responding to an online questionnaire. The relatively low rate of vaccination intent (30.12%, and 34.99% being unsure of their intent) was related to a sense of invulnerability regarding illness contraction and symptom severity. Most individuals were skeptical that H1N1 would be widespread, believing that less than 10% of the population would contract H1N1. Yet, they also indicated that their attitudes would change once a single person they knew contracted the illness. Also, worry regarding H1N1 was related to self-contraction risk and odds of individuals seeking vaccination. Moreover, vaccination intent was related to the perception that the threat was not particularly great, mistrust of the media to provide accurate information regarding H1N1, and whether individuals endorsed problem-focused versus avoidant coping strategies. Given the role media plays in public perceptions related to a health crisis, trust in this outlet and credibility regarding the threat are necessary for adherence to recommended measures to minimize health risk.
Flue and other respiratory diseases morbidity of servicemen of training students are researched. Epidemiological and economic effectiveness of flue vaccine "Bakcuspun" (Vaksigrip) is estimated. Its non-specific protective effect in case of acute respiratory diseases and pyodermia is shown.
Commercial inactivated parenteral influenza vaccines reduced febrile (> or = 38 degrees C) respiratory illness by 53% (95% CL: 41-63%) during a 3 week outbreak in 1998 when A/Sydney/5/97(H3N2)-like influenza viruses were shown to be the predominant etiological agents and an older antigenic variant, A/Nanchang/933/95, served as the vaccine virus. The calculatory efficacy for preventing virologically diagnosed influenza infections was 57% (95% CL: 40-68%). The study population consisted of 1374 young male military conscripts. Vaccination coverage on a voluntary basis was 67%. Vaccination was ineffective in preventing febrile illness during a second epidemic wave lasting 2 weeks when mainly adenoviruses were shown to have been circulating in the garrison. Out of the 36 nasopharyngeal aspirates positive for influenza A by antigen detection, 18 A/Sydney/5/97-like strains (10 from non-vaccinated and eight from vaccinated subjects) and two A/Nanchang/933/95-like strains (both from non-vaccinated subjects) were isolated in MDCK cell cultures. Intraepidemic variation was detected among the A/Sydney/5/97-like field strains in their HA1 sequences and reactivity in HI tests, but no evidence was obtained that this variation would have been of significance to the virus in breaking through the vaccination-induced immunity.
Schoolchildren of 30 to 34 schools of Novgorod were vaccinated over a three-year period with Russian live cold-adapted attenuated vaccine for children and whole-virus inactivated vaccines and placebo for comparative field study of the vaccines properties and efficacy. In control trials both bi- and trivalent live attenuated vaccines were well tolerated and areactogenic. A whole-virus inactivated trivalent vaccine induced mild and moderate fever and local reactions in 2-4% of the vaccinees. Special observations are necessary to establish the possibility of use and to determine a dose of this inactivated vaccine for immunization of children, especially those of 7-10 years of age. All the vaccines induced HI antibody production in 50-80% and antineuraminidase in 50-70% of seronegative children. The pattern of the results was similar to that in revaccinated children with preexisting antibody at a level of 1:20, but much lower in children with the initial titre above 1:20. After the 3rd year of vaccination the immune response of the vaccinees was similar, most of the results depending on the initial antibody titre and also on the change of vaccine strains. This raises a question of the expediency of annual influenza revaccination of the same person after 2 years of successful immunization and of the necessity of vaccine strains replacement after 2-3 years of use.
This study was carried out to compare reactogenicity, immunogenicity, and efficacy of live attenuated and inactivated influenza vaccines prepared from influenza A/Philippines/2/82-like virus strains. Schoolchildren of a boarding school of Moscow were randomly divided into three groups: (1) vaccinated with a live attenuated vaccine, (2) vaccinated with inactivated influenza vaccine, and (3) given placebo. Both vaccines were well tolerated by the children, with practically no severe general or local reactions. The inactivated vaccine was found to be superior to the live one in its capacity to stimulate humoral immunity studied by HI, EIA, and microneutralization tests. In 69.7% of the children given the inactivated vaccine, seroconversion to the vaccine strain was detected by two or three methods of antibody titration used. Only 35.4% seroconversions were demonstrated in children immunized with the live influenza vaccine. Enzyme immunoassay was found to be a more sensitive but less specific method for antibody titration as compared with HI test whereas microneutralization proved to be more specific but less sensitive for titration of antibodies to influenza A (H3N2) viruses.