[AF] vacuna varicela

[Ramon Diaz-Alersi]

Pediatrics. 2007 Jul;120(1):221-31.

Prevention of varicella: recommendations for use of varicella vaccines in
children, including a recommendation for a routine 2-dose varicella
immunization
schedule.

American Academy of Pediatrics Committee on Infectious Diseases.

National varicella immunization coverage using the current 1-dose immunization
strategy has increased among vaccine-eligible children 19 through 35 months of
age from 27% in 1997 to 88% by 2005. These high immunization rates
have resulted
in a 71% to 84% decrease in the reported number of varicella cases, an 88%
decrease in varicella-related hospitalizations, a 59% decrease in
varicella-related ambulatory care visits, and a 92% decrease in
varicella-related
deaths in 1- to 4-year-old children when compared with data from the prevaccine
era. Despite this significant decrease, the number of reported cases
of varicella
has remained relatively constant during the past 5 to 6 years. Since vaccine
effectiveness for prevention of disease of any severity has been 80% to 85%, a
large number of cases of varicella continue to occur among people who already
have received the vaccine (breakthrough varicella), and outbreaks of varicella
have been reported among highly immunized populations of
schoolchildren. The peak
age-specific incidence has shifted from 3- to 6-year-old children in the
prevaccine era to 9- to 11-year-old children in the postvaccine era
for cases in
both immunized and unimmunized children during these outbreaks. Outbreaks of
varicella are likely to continue with the current 1-dose immunization strategy.
After administration of 2 doses of varicella vaccine in children, the immune
response is markedly enhanced, with > 99% of children achieving an antibody
concentration (determined by glycoprotein enzyme-linked immunosorbent
assay) of >
or = 5 U/mL (an approximate correlate of protection) and a marked increase in
geometric mean antibody titers after the second vaccine dose. The estimated
vaccine efficacy over a 10-year observation period of 2 doses for prevention of
any varicella disease is 98% (compared with 94% for 1 dose), with 100% efficacy
for prevention of severe disease. Recipients of 2 doses of varicella
vaccine are
3.3-fold less likely to have breakthrough varicella, compared with
those who are
given 1 dose, during the first 10 years after immunization. To achieve greater
levels of immunity with fewer serosusceptible people, greater
protection against
breakthrough varicella disease, and reduction in the number of outbreaks that
occur nationwide among school-aged populations, a 2-dose varicella immunization
strategy is now recommended for children > or = 12 months of age.

Saludos
---
Ramón Díaz-Alersi



> El 23 de junio de 2009 12:54, Wenceslao
> Ferrando escribió:
> Caso:
> Niña vacunada de varicela a los 18 meses, en la actualidad tiene 5 años y el