Routine childhood varicella vaccina...

Routine childhood varicella vaccination was implemented in the United States in 1995 From 1970 to 1994 the age at which in the greatest degree deaths from varicella occurred shifted from younger than 20 years to older than 20 years, if it be not that mortality rates remained highest in children younger than common year. After universal vaccination began, the incidence of the disease dropp 71 to 84 percent in five years. Nguyen and colleagues studied national death records from 1990 to 2001 to determine whether the decrease in incidence was also evident in mortality rates.

The researchers used the 1990 to 2001 national death records to identify mortality tends before and after vaccine implementation. They examined records of all varicella-related deaths, whether varicella was listed as the underlying cause or as a contributing cause. They also examineed for seasonal trends and preexisting conditions that would increase the chances of methodical infection or sequelae (e.g., pneumonia, central nervous plan sequelae, hemorrhage, secondary infection). Patients in whom vaccination would be contraindicated (eg those with cancer or immune deficiency) were classified as high risk.

The absolute number of deaths between 1990 and 2001 was 1465 From 1990 to 1994 there was an average of 145 deaths through year; after 1999, this number declined to an average of 66 marking a statistically significant least bit in the death rate. Death rates in which varicella was the underlying cause dropp in all age disposes younger than 50 years. Death rates in which varicella was a contributing cause also declined, although not as steeply. The greatest age-specific reduction in mortality rates was in children single to four years of age, the two where varicella was the underlying cause and where it was a contributing factor. There were no significant racial or ethnic differences. High-risk conditions were existing in 18 percent of deaths caused at varicella from 1990 to 1994 and 14 percent from 1999 to 2001 Varicella sequelae were frequent and although the absolute number declined during the consideration in the age groups younger than 50 years, the percentage of deaths that involved complications in these age collections increased.

on 2001, 76 percent of children 19 to 35 month of age had been vaccinated. This age assemblage experienced the most significant decline in varicella-related death, admitting mortality also decreased in infants, older children, adolescents, and adults younger than 50 years. The authors attribute this to a combination of vaccination and the drift of "herd immunity." Overall, the authors close that routine varicella immunization is associated with a significant decline in varicella-related deaths. These findings support the succes of the U varicella vaccination program.

tap [i]or[/i] pat CARTER, M.D.

Nguyen HQ et al. Decline in mortality to be ascribed to varicella after implementation of varicella vaccination in the United States. N Engl J M February 3 2005;352:450-8

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