Related Experiment Videos
Postlicensure study of varicella vaccine effectiveness in a day-care setting
D A Clements1, S P Moreira, P M Coplan
1Duke Children's Hospital, Durham, NC, USA.
Insights
The varicella vaccine is highly effective in preventing chickenpox in children attending daycare. This study found an 83% vaccine effectiveness, demonstrating its benefit in reducing disease incidence.
Area of Science:
- Pediatric Infectious Diseases
- Vaccinology
- Public Health
Background:
- The varicella vaccine was licensed in the U.S. in 1995.
- Assessing vaccine acceptance and impact on varicella incidence in children is crucial.
Purpose of the Study:
- To evaluate the effectiveness of the varicella vaccine.
- Focus on children in North Carolina day-care centers.
Main Methods:
- Dynamic cohort study across 11 day-care centers.
- Compared varicella attack rates in vaccinated vs. unvaccinated children.
- Utilized person-time for calculations.
Main Results:
- 134 varicella cases in unvaccinated children, 11 in vaccinated.
- Attack rates: 2.49 (vaccinated) vs. 14.66 (unvaccinated).
- Overall vaccine effectiveness was 83% for mild/moderate disease.
Conclusions:
- Varicella vaccine shows significant benefit in day-care settings.
- Effectively prevents and modifies wild-type varicella disease.
- Supports routine varicella vaccination for children.
Background:
Varicella vaccine has been licensed for use in the United States since the spring of 1995. The acceptance of the vaccine and its effect on varicella incidence in children is important.
Aim:
To document the effectiveness of the varicella vaccine in children attending day care in 11 centers in North Carolina.
Methods:
A dynamic cohort study design was used in 11 day-care centers in North Carolina. Multiple cross-sectional evaluations were performed and children were noted to be vaccinated or not and diseased or not. Vaccine effectiveness was estimated by comparing the varicella attack rate in the vaccinated with the varicella attack rate in the unvaccinated. Person time was used as the denominator for all calculations.
Results:
During the study period February 1, 1996, to September 1, 1997, 134 cases of varicella occurred in the unvaccinated and 11 cases occurred in the vaccinated children. The attack rates in the vaccinated and unvaccinated were 2.49 and 14.66, respectively, for an overall vaccine effectiveness of 83% for mild/moderate disease.
Conclusions:
In the day-care setting varicella vaccine demonstrated benefit in preventing and modifying wild-type varicella disease.