Background: Acyclovir has the potential to shorten the course of illness which may result in reduced costs and morbidity.
Objectives: 1) To examine the evidence evaluating the efficacy of acyclovir in alleviating symptoms and shortening the duration of illness. 2) To examine complications of chickenpox and adverse effects associated with acyclovir as reported in the relevant trials.
Search strategy: We searched the Cochrane Controlled Trials Register (2002, Issue 2), MEDLINE (January 1966 to October 2001), EMBASE (1988 to September 2001). The reference lists of all relevant articles were reviewed. The primary author of relevant studies and the pharmaceutical company that manufactures acyclovir were contacted.
Selection criteria: Randomized controlled trials that evaluated otherwise healthy children 0-18 years of age with chickenpox.
Data collection and analysis: Two reviewers independently reviewed the studies for eligibility. Two reviewers independently assessed methodological quality of the relevant studies using the Jadad scale and allocation concealment. Differences were resolved by consensus. Data were extracted by one reviewer using a structured form and checked by a second. Continuous data were converted to the weighted mean difference (WMD). Weighted mean differences were not combined into an overall estimate due to the varied age groups between studies. There were too few studies to consider statistical heterogeneity between studies (i.e., differences in reported effects), to perform subgroup or sensitivity analyses, or to assess for publication bias.
Main results: Three studies were included. Study quality was three (n=2) and four (n=1) on the Jadad scale. Acyclovir was associated with a reduction in the number of days with fever, from -1.0 (95% CI -1.5,-0.5) to -1.3 (95% CI -2.0,-0.6). Results were inconsistent with respect to the number of days to no new lesions, the maximum number of lesions and the number of days to the relief of itching. There were no clinically important differences between acyclovir and placebo with respect to complications associated with chickenpox or adverse effects associated with the drug.
Reviewer's conclusions: Acyclovir appears to be effective in reducing the number of days with fever among otherwise healthy children with chickenpox. The results were inconsistent with respect to the number of days to no new lesions, relief of itchiness and maximum number of lesions. The clinical importance of acyclovir treatment in otherwise healthy children remains controversial.