No abstract

Infants with CF incurring respiratory virus infection are at significant risk for LRTI, for hospitalization, and for deterioration in lung function that persists months after the acute illness.

In Houston the temporal occurrence of infections with parainfluenza virus type 3 has evolved from an endemic to an epidemic pattern. Continuous virological surveillance for six years demonstrated that most infections occurred the late winter or spring after influenza virus activity. At least two-thirds of children observed in the Houston Family Study were infected with this virus in each of the first two years of life, and the risk of illness was about 30/100 children per year. After two years of age, the infection and illness rates dropped to 32 and 8 per 100 child-years, respectively. Most lower-respiratory-tract disease was associated with primary infection, and the risk for infection was greater during the second year for the smaller proportion of children who escaped infection during the first year. The risk during the first year may have been modified by passively acquired maternal antibody.

The combination of increased maternal antibody titers that should result from influenza immunization and the lesser risk of influenza in the first 6 months of life allows initiation of active immunization of children after 6 months of age.