Journal Article

Household Transmission of 2009 Pandemic Influenza A (H1N1) Virus in the United States

Reed, Carrie, Donnelly, Christl A, Ghani, Azra C, Finelli, Lyn, Cauchemez, Simon, Kent, Charlotte K, Ferguson, Neil M, Fraser, Christophe

2009

Overview

Factors relating to the transmission of the 2009 H1N1 virus from an index patient to a household contact are poorly understood. This study shows that when a member of the household became infected with the 2009 H1N1 influenza virus, younger household contacts (<18 years of age) were twice as susceptible to an acute respiratory illness as were those 19 to 50 years of age, whereas contacts older than 50 years were less susceptible. A smaller household was associated with (proportionally) increased transmission to household contacts. This study shows that when a member of the household became infected with the 2009 H1N1 influenza virus, household contacts less than 18 years of age were twice as susceptible to an acute respiratory illness as were those 19 to 50 years of age, whereas contacts older than 50 years were less susceptible. As of June 11, 2009, a total of 17,855 probable or confirmed cases of 2009 H1N1 virus infection, including 45 deaths, had been reported in the United States. 1 – 3 The risk factors for transmission of this emerging virus remain largely uncharacterized, particularly in subgroups such as households. Most people who have 2009 H1N1 influenza are advised to stay home until they have been afebrile for at least 24 hours. 4 This practice puts other household members, who care for the patient when he or she is most infectious, at risk for infection. But so far, neither this risk nor the potential . . .

• Publisher: Massachusetts Medical Society
• Subject: Adolescent / Adult / Age Factors / Biological and medical sciences / Child / Child, Preschool / Data collection / Disease Outbreaks / Disease Transmission, Infectious - statistics & numerical data / Family Characteristics / Family Health / Female / General aspects / Human viral diseases / Humans / Infant / Infectious diseases / Influenza A Virus, H1N1 Subtype / Influenza, Human - epidemiology / Influenza, Human - transmission / Male / Medical sciences / Middle Aged / Miscellaneous / Pandemics / Patients / Public health. Hygiene / Public health. Hygiene-occupational medicine / Risk factors / Swine flu / United States / Viral diseases / Viral diseases of the respiratory system and ent viral diseases / Young Adult