Background: Acyclovir has the potential to shorten the course of illness which may result in reduced costs and morbidity associated with chickenpox.
Objectives: 1) To examine the evidence evaluating the efficacy of acyclovir in alleviating symptoms of chickenpox 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 Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2, 2005), MEDLINE (January 1966 to June 2005), and EMBASE (1988 to June 2005). 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 zero to 18 years of age, with chickenpox.
Data collection and analysis: Two authors independently reviewed the studies for eligibility. Two authors 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 author using a structured form and checked by a second. Continuous data were converted to the weighted mean difference (WMD). Weighted mean differences were combined into an overall estimate using random effects. There were too few studies to consider exploring statistical heterogeneity between studies (i.e., differences in reported effects), formally, 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 (-1.1 days, 95% CI -1.3 to -0.9) and in reducing the maximum number of lesions (-76 lesions, -145 to -8). Results were less supportive with respect to the number of days to no new 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 treatment.
Authors' conclusions: Acyclovir appears to be effective in reducing the number of days with fever and the maximum number of lesions among otherwise healthy children with chickenpox. The results were less convincing with respect to the number of days to no new lesions and relief of itchiness. The clinical importance of acyclovir treatment in otherwise healthy children remains uncertain.