This article is more than 5 years old. Information may no longer be current.
CDC: Younger children most susceptible to A(H3N2)v flu virus
Click Here to Manage Email Alerts
Children aged younger than 10 years are less likely to develop cross-reactive antibodies to A(H3N2)v influenza virus, and the seasonal vaccine is unlikely to protect against this strain, according to data from the CDC.
Of 12 reported patients who had influenza A(H3N2)v virus in 2011, 11 were children aged younger than 10 years. This is an increase in cases compared with the previous 2 years, when only eight patients were reported, CDC researchers said. However, they added, this uptick may have correlated with increased surveillance.
The researchers reported that there appears to be a correlation between age and cross-reactive antibodies, indicating that the older the individual, the more likely cross-reactive antibodies develop. Adults and older children developed cross-reactive antibodies to A(H3N2) influenza virus, but younger children developed few or none and were, consequently, more susceptible.
The researchers said the 2010-2011 seasonal influenza vaccine “had no impact on cross-reactive antibody levels in children aged younger than 3 years but did boost cross-reactive antibodies in adults aged 18 to 49 years and aged 65 years and older, but only to levels that were lower than to seasonal A(H3N2) virus.”
Although younger people likely remain susceptible, the researchers said “receipt of seasonal influenza vaccine continues to be recommended to protect against circulating human influenza viruses for all age groups and might provide some protection against A(H3N2)v infection in the adult population. A vaccine virus specific for A(H3N2)v has been developed and could be used to produce an H3N2v vaccine, if needed.”
Click Here to Manage Email Alerts