Objective: To know the natural history of the first wave of pandemic influenza A(H1N1)pdm09 in the Southern hemisphere, through the detection of antibodies against influenza A(H1N1)pdm09 in a selected community, to es...Objective: To know the natural history of the first wave of pandemic influenza A(H1N1)pdm09 in the Southern hemisphere, through the detection of antibodies against influenza A(H1N1)pdm09 in a selected community, to estimate the population attack rate and its variations, the consultation rates, hospitallization and mortality rates. Methodology: A representative random sample of the population of a commune in Chile (San Felipe) was interviewed and taken blood samples between January and March 2010. A study against the antibodies of the influenza A(H1N1) pdm09 virus was conducted, by the technique of the Hemaglutination Inhibition (HAI) according to standardized methodology. Subjects with antibody titers ≥1:40 were considered positive. Results: 13.5% of the population of San Felipe had antibodies against influenza A(H1N1)pdm09;this percentage reached 30% of the population between 0 and 18 years and 6.1% among those over 19 years. The age variable was the only factor that evidenced significant differences in the prevalence of antibodies. There were no significant differences related to gender, vaccination history against seasonal inluenza, or comorbidity. 51% of people with positive serology showed IN-FLUENZA-LIKE SYMPTOMS. Conclusions: A relevant percentage of subclinical disease was detected in the first pandemic wave in Chile and the proportion of people with SARI and deaths was small. Data from epidemiological surveillance were useful to estimate the trend of TSI but not its magnitude.展开更多
This paper presents the results of a pre-clinical study of the immunogenicity and efficacy of an egg-derived,inactivated,whole-virion adjuvanted vaccine (Refluvac) on ferret models.For this purpose,groups of eight fer...This paper presents the results of a pre-clinical study of the immunogenicity and efficacy of an egg-derived,inactivated,whole-virion adjuvanted vaccine (Refluvac) on ferret models.For this purpose,groups of eight ferrets (6 to 7 months old) were injected with 0.5 mL of vaccine specimens containing 3.75,7.5 or 15.0 μg of virus hemagglutinin.Administration was intramuscular and given either as a single dose or as two doses 14 days apart.All vaccine specimens manifested immunogenicity in ferrets for single (HI titer,from 51±7 to 160±23) and double (HI titer,from 697±120 to 829±117) administrations.To assess the protective effects of the vaccine,ferrets from the vaccinated and control groups were infected intranasally with pandemic virus А/California/7/09 (Н1N1) pdm09 at a dose of 106 EID 50/0.5 mL.Fourteen days post-infection,the ferrets inoculated with single or double vaccines containing 3.75,7.5 or 15.0 μg of hemagglutinin per dose showed no signs of influenza infection,weight loss,or body temperature rise,and no premature deaths occurred.The number of vaccinated ferrets shedding the virus via the upper airway,as well as the amount of virus shed after infection,was significantly reduced in comparison with animals from the control group.Based on our results,we suggest that a single vaccination at a dose of 3.75 or 7.5 μg hemagglutinin be used for Phase I clinical trials.展开更多
文摘Objective: To know the natural history of the first wave of pandemic influenza A(H1N1)pdm09 in the Southern hemisphere, through the detection of antibodies against influenza A(H1N1)pdm09 in a selected community, to estimate the population attack rate and its variations, the consultation rates, hospitallization and mortality rates. Methodology: A representative random sample of the population of a commune in Chile (San Felipe) was interviewed and taken blood samples between January and March 2010. A study against the antibodies of the influenza A(H1N1) pdm09 virus was conducted, by the technique of the Hemaglutination Inhibition (HAI) according to standardized methodology. Subjects with antibody titers ≥1:40 were considered positive. Results: 13.5% of the population of San Felipe had antibodies against influenza A(H1N1)pdm09;this percentage reached 30% of the population between 0 and 18 years and 6.1% among those over 19 years. The age variable was the only factor that evidenced significant differences in the prevalence of antibodies. There were no significant differences related to gender, vaccination history against seasonal inluenza, or comorbidity. 51% of people with positive serology showed IN-FLUENZA-LIKE SYMPTOMS. Conclusions: A relevant percentage of subclinical disease was detected in the first pandemic wave in Chile and the proportion of people with SARI and deaths was small. Data from epidemiological surveillance were useful to estimate the trend of TSI but not its magnitude.
文摘This paper presents the results of a pre-clinical study of the immunogenicity and efficacy of an egg-derived,inactivated,whole-virion adjuvanted vaccine (Refluvac) on ferret models.For this purpose,groups of eight ferrets (6 to 7 months old) were injected with 0.5 mL of vaccine specimens containing 3.75,7.5 or 15.0 μg of virus hemagglutinin.Administration was intramuscular and given either as a single dose or as two doses 14 days apart.All vaccine specimens manifested immunogenicity in ferrets for single (HI titer,from 51±7 to 160±23) and double (HI titer,from 697±120 to 829±117) administrations.To assess the protective effects of the vaccine,ferrets from the vaccinated and control groups were infected intranasally with pandemic virus А/California/7/09 (Н1N1) pdm09 at a dose of 106 EID 50/0.5 mL.Fourteen days post-infection,the ferrets inoculated with single or double vaccines containing 3.75,7.5 or 15.0 μg of hemagglutinin per dose showed no signs of influenza infection,weight loss,or body temperature rise,and no premature deaths occurred.The number of vaccinated ferrets shedding the virus via the upper airway,as well as the amount of virus shed after infection,was significantly reduced in comparison with animals from the control group.Based on our results,we suggest that a single vaccination at a dose of 3.75 or 7.5 μg hemagglutinin be used for Phase I clinical trials.