Many thanks to the Post-Dispatch for alerting readers to the spread of flu across the country ("Early flu bug has hit children the hardest," Jan. 10). Readers may also be interested in the following information regarding this year's outbreak:
- There are three circulating "strains" of flu identified by the CDC as of the last week of December, one in the group known as Type A influenza and two in the group called Type B.
- The available influenza vaccines — either the one given by injection (made of inactivated portions of the virus) or the nasal spray (comprised of weakened virus) — include protection for over essentially all of the Type A strain and 70 percent of the Type B strains. Overall, most flu cases (about 85 percent) have been caused by the Type A strains, and only about 5 percent of cases have been caused by a Type B strain not included in this year's vaccine.
- Children and adolescents are disproportionately infected with Type B strains.
Thus, vaccination remains the best defense against the flu, yet only about 40 percent of Americans have been vaccinated in this flu season. The illness can be particularly severe in the very young — who are often not vaccinated — and the elderly. The flu vaccine is safe, and it is not too late to get vaccinated. Vaccination is approved for just about everyone, including infants 6 months of age and older. Frequent hand washing has also been demonstrated to reduce flu transmission even among those not vaccinated.
Dr. Alan Zelicoff • St. Louis
Director, Institute for Biosecurity, St. Louis University