Illness and Diseases

Randomization. Randomization lists were prepared by a biostatistician (B.J.C.). Eligible study participants were randomly allocated to the TIV group or placebo group in the ratio 3:2 using a random number generator (R software). A block‐randomization sequence was generated with randomly permuted block sizes of 5, 10, and 15. More households were allocated to the TIV […]

Serum specimens were collected from study subjects at baseline immediately before vaccination (November–December 2008), 1 month after vaccination, after the winter influenza season (“mid‐season”; April 2009) and at the end of the follow‐up period (August–October 2009). Serum specimens were also collected from all household contacts at baseline, at mid‐season, and post‐season. All subjects and household […]

Trivalent inactivated influenza vaccine (TIV) is effective in preventing infection and illness associated with influenza A and B viruses in children during seasons when the vaccine components closely match circulating strains. On the basis of evidence from ecological studies, intervention trials, and simulation models, some health authorities have recommended vaccination of school‐age children against seasonal […]

Canadian investigators published the results of 4 observational studies in April 2010 that purported to show an association between the 2008 TIV and nH1N1 illness. The 4 studies were a test‐negative case‐control study based on the Canadian sentinel vaccine effectiveness monitoring system in 4 provinces, a conventional case‐control design in Quebec that used population control […]

A novel influenza A(H1N1) virus appeared in Mexico in March 2009. The prototype strain, A/California/09/2009(H1N1), was identified in April 2009, and the virus was found to have surface antigens that are distinct from those of the circulating seasonal influenza A(H1N1) virus. An early survey of antibody prevalence suggested that many persons 60 years of age […]