Tuesday, January 15, 2013

Modeling study finds low pandemic risk from variant H3N2

[You can refer to the H3N2 Variant Information List articles posted on the right side-bar.]

January 15, 2013 - CIDRAP
Novel swine-origin variant H3N2 influenza (H3N2v) does not currently pose a substantial pandemic risk, according to Canadian flu experts, but that could change over time, according to a study in PLoS One. The scientists estimated potential epidemic attack rates (ARs) based on age-specific estimates of serosusceptibility and social interactions. They used a contact network model established for Greater Vancouver to estimate ARs for H3N2v, pandemic 2009 H1N1, and a former seasonal H3N2 strain. The model factored in typical flu characteristics, basic reproduction number, social contacts, and age-specific seroprotection rates (SPRs). The researchers determined an AR of 6% for H3N2v, meaning that 6% of the population exposed would be infected, but the AR grew to 16% in kids 6 to 11 years old. If they modified the SPRs, however, H3N2v ARs of  20% or higher were possible. The authors conclude, "If H3N2v epidemics do occur, overall community ARs are unlikely to exceed typical seasonal influenza experience [which typically involves ARs of 5% to 15%]. However, risk assessment may change with time and depends crucially upon the validation of epidemiological features of influenza."
Jan 11 PLoS One study


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