tetano
Editor, Senior Moderator
Seroprevalence of Pandemic Influenza H1N1 in Ontario from January 2009?May 2010. PLoS ONE 6(11): e26427. doi:10.1371/journal.pone.0026427
Camille Achonu1, Laura Rosella1,5, Jonathan B. Gubbay2,6, Shelley Deeks1,5, Anu Rebbapragada2, Tony Mazzulli2, Don Willison1, Julie Foisy1, Allison McGeer5,7, Ian Johnson1,5, Marie LaFreniere1, Caitlin Johnson1, Jacqueline Willmore3, Carmen Yue4, Natasha S. Crowcroft1,5,6*
1 Department of Surveillance and Epidemiology, Public Health Ontario, Toronto, Ontario, Canada, 2 Public Health Laboratories, Public Health Ontario, Toronto, Ontario, Canada, 3 Ottawa Public Health, Nepean, Ontario, Canada, 4 Toronto Public Health, Toronto, Ontario, Canada, 5 Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada, 6 Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada, 7 Department of Microbiology, Mount Sinai Hospital, Toronto, Ontario, Canada
Abstract Top
Background
We designed a seroprevalence study using multiple testing assays and population sources to estimate the community seroprevalence of pH1N1/09 and risk factors for infection before the outbreak was recognized and throughout the pandemic to the end of 2009/10 influenza season.
Methods
Residual serum specimens from five time points (between 01/2009 and 05/2010) and samples from two time points from a prospectively recruited cohort were included. The distribution of risk factors was explored in multivariate adjusted analyses using logistic regression among the cohort. Antibody levels were measured by hemagglutination inhibition (HAI) and microneutralization (MN) assays.
Results
Residual sera from 3375 patients and 1024 prospectively recruited cohort participants were analyzed. Pre-pandemic seroprevalence ranged from 2%?12% across age groups. Overall seropositivity ranged from 10%?19% post-first wave and 32%?41% by the end of the 2009/10 influenza season. Seroprevalence and risk factors differed between MN and HAI assays, particularly in older age groups and between waves. Following the H1N1 vaccination program, higher GMT were noted among vaccinated individuals. Overall, 20?30% of the population was estimated to be infected.
Conclusions
Combining population sources of sera across five time points with prospectively collected epidemiological information yielded a complete description of the evolution of pH1N1 infection.
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0026427
Camille Achonu1, Laura Rosella1,5, Jonathan B. Gubbay2,6, Shelley Deeks1,5, Anu Rebbapragada2, Tony Mazzulli2, Don Willison1, Julie Foisy1, Allison McGeer5,7, Ian Johnson1,5, Marie LaFreniere1, Caitlin Johnson1, Jacqueline Willmore3, Carmen Yue4, Natasha S. Crowcroft1,5,6*
1 Department of Surveillance and Epidemiology, Public Health Ontario, Toronto, Ontario, Canada, 2 Public Health Laboratories, Public Health Ontario, Toronto, Ontario, Canada, 3 Ottawa Public Health, Nepean, Ontario, Canada, 4 Toronto Public Health, Toronto, Ontario, Canada, 5 Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada, 6 Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada, 7 Department of Microbiology, Mount Sinai Hospital, Toronto, Ontario, Canada
Abstract Top
Background
We designed a seroprevalence study using multiple testing assays and population sources to estimate the community seroprevalence of pH1N1/09 and risk factors for infection before the outbreak was recognized and throughout the pandemic to the end of 2009/10 influenza season.
Methods
Residual serum specimens from five time points (between 01/2009 and 05/2010) and samples from two time points from a prospectively recruited cohort were included. The distribution of risk factors was explored in multivariate adjusted analyses using logistic regression among the cohort. Antibody levels were measured by hemagglutination inhibition (HAI) and microneutralization (MN) assays.
Results
Residual sera from 3375 patients and 1024 prospectively recruited cohort participants were analyzed. Pre-pandemic seroprevalence ranged from 2%?12% across age groups. Overall seropositivity ranged from 10%?19% post-first wave and 32%?41% by the end of the 2009/10 influenza season. Seroprevalence and risk factors differed between MN and HAI assays, particularly in older age groups and between waves. Following the H1N1 vaccination program, higher GMT were noted among vaccinated individuals. Overall, 20?30% of the population was estimated to be infected.
Conclusions
Combining population sources of sera across five time points with prospectively collected epidemiological information yielded a complete description of the evolution of pH1N1 infection.
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0026427