A controlled trial of acyclovir for chickenpox in normal children.

BACKGROUND: Chickenpox, the primary infection caused by the varicella-zoster virus, affects more than 3 million children a year in the United States. Although usually self-limited, chickenpox can cause prolonged discomfort and is associated with infrequent but serious complications. METHODS: To evaluate the effectiveness of acyclovir for the treatment of chickenpox, we conducted a multicenter, double-blind, placebo-controlled study involving 815 healthy children 2 to 12 years old who contracted chickenpox. Treatment with acyclovir was begun within the first 24 hours of rash and was administered by the oral route in a dose of 20 mg per kilogram of body weight four times daily for five days. RESULTS: The children treated with acyclovir had fewer varicella lesions than those given placebo (mean number, 294 vs 347; P less than 0.001), and a smaller proportion of them had more than 500 lesions (21 percent, as compared with 38 percent with placebo; P less than 0.001). In over 95 percent of the recipients of acyclovir no new lesions formed after day 3, whereas new lesions were forming in 20 percent of the placebo recipients on day 6 or later. The recipients of acyclovir also had accelerated progression to the crusted and healed stages, less itching, and fewer residual lesions after 28 days. In the children treated with acyclovir the duration of fever and constitutional symptoms was limited to three to four days, whereas in 20 percent of the children given placebo illness lasted more than four days. There was no significant difference between groups in the distribution of 11 disease complications (10 bacterial skin infections and 1 case of transient cerebellar ataxia). Acyclovir was well tolerated, and there was no significant difference between groups in the titers of antibodies against varicella-zoster virus. CONCLUSIONS: Acyclovir is a safe treatment that reduces the duration and severity of chickenpox in normal children when therapy is initiated during the first 24 hours of rash. Whether treatment with acyclovir can reduce the rare, serious complications of chickenpox remains uncertain.

Acyclovir treatment of varicella in otherwise healthy children.

STUDY OBJECTIVE: To determine whether acyclovir administered orally affects the duration and severity of varicella in otherwise normal children. DESIGN: Randomized, placebo-controlled, double-blind trial. SETTING: Patients' residence and university hospital clinic. PATIENTS: One hundred five children between 5 and 16 years of age with laboratory-confirmed varicella entered the study. Of the 102 who were included in the final analysis, 50 received acyclovir and 52 received placebo. INTERVENTION: Placebo or acyclovir was given orally four times daily, for 5 to 7 days. The acyclovir dose was adjusted as follows: 5 to 7 years of age, 20 mg/kg; 7 to 12 years, 15 mg/kg; and 12 to 16 years, 10 mg/kg. MEASUREMENTS AND MAIN RESULTS: Acyclovir recipients, compared with the placebo group, defervesced sooner (median, 1 day vs 2 days; p = 0.001), experienced onset of cutaneous healing sooner, as reflected by a decrease in number of lesions (median, 3 days vs 2 days; p = 0.002), and had fewer skin lesions (median, 500 vs 336; p = 0.02). Acyclovir did not significantly change the rate of complications of varicella (10% in the acyclovir group vs 13.5% among placebo subjects). Adverse drug effects were not observed. Acyclovir recipients had lower geometric mean serum antibody titers to varicella-zoster virus than their placebo counterparts 4 weeks after the onset of illness, but antibody titers in both groups were similar 1 year later. CONCLUSIONS: These results provide evidence that acyclovir is useful and well tolerated for treatment of varicella in otherwise healthy children.

Identification of small DNA fragments synthesized in herpes simplex virus-infected cells in the presence of acyclovir.

The effect of acyclovir on DNA synthesized in cells infected with herpes simplex virus type 1 was examined. DNA that was synthesized in infected cells in the presence of acyclovir during a short pulse with [3H]thymidine remained near the top of an alkaline sucrose gradient after centrifugation. The sedimentation characteristics of labeled DNA were not changed after chasing in isotope-free medium. The slowly sedimenting DNA was identified as viral in origin by hybridization to purified herpes simplex virus nucleocapsid DNA. When cells were infected with acyclovir-resistant virus containing mutations in the polymerase gene, the viral DNA synthesized in the presence of acyclovir was chased into high-molecular-weight DNA. These findings are consistent with chain termination of herpes simplex virus DNA in virus-infected cells.

Effect of acyclovir on viral protein synthesis in cells infected with herpes simplex virus type 1.

The effect of the antiviral agent 9-(2-hydroxyethoxymethyl)guanine (acyclovir) on herpes simplex virus type 1 protein synthesis during virus replication was examined. Treatment of infected cells with acyclovir markedly affected the amounts of the four major glycosylated and certain non-glycosylated viral polypeptides synthesized; other viral polypeptides were made in normal amounts. The reduced amount of late protein synthesis was most likely due to the inhibition of progeny viral DNA synthesis by acyclovir.

Acyclovir inhibition of viral DNA chain elongation in herpes simplex virus-infected cells.

The effect of acyclovir on DNA synthesized in HSV-1-infected cells was examined. Viral DNA synthesis was significantly reduced in the presence of 10 microM acyclovir monitored by cRNA-DNA hybridization and isopycnic centrifugation in cesium chloride. DNA synthesized in infected cells in the presence of acyclovir appeared to be chain-terminated when evaluated by rate zonal centrifugation in alkaline sucrose. Cellular DNA synthesis in actively replicating uninfected cells in the presence of acyclovir was evaluated by isopycnic centrifugation. Cellular DNA synthesis appeared unaffected at concentrations of acyclovir up to 100 microM.