The quality of evidence is downgraded by study limitations (lack of/unclear allocation concealment).
A Cochrane review «Interventions for prevention of herpes simplex labialis (cold sores on the lips)»1 «Chi CC, Wang SH, Delamere FM et al. Interventions for prevention of herpes simplex labialis (cold sores on the lips). Cochrane Database Syst Rev 2015;8():CD010095. »1 included 32 studies with a total of 2640 immunocompetent subjects covering 19 treatments. Only studies on oral antiviral agents are referred here.
The evidence for short-term (≤ 1 month) use of oral aciclovir in preventing recurrent HSL was inconsistent across the doses used in the studies: 2 RCTs showed reduced recurrence of HSL with aciclovir 400 mg twice daily (RR 0.26, 95% CI 0.13 to 0.51; n = 177), while 1 RCT testing aciclovir 800 mg twice daily and 2 RCTs testing 200 mg 5 times daily found no similar preventive effects (RR 1.08, 95% CI 0.62 to 1.87; n = 237; and RR 0.46, 95% CI 0.20 to 1.07; n = 66). The direction of intervention effect was unrelated to the risk of bias. The evidence from 1 RCT for the effect of short-term use of valaciclovir in reducing recurrence of HSL by clinical evaluation was uncertain (RR 0.55, 95% CI 0.23 to 1.28; n = 125), as was the evidence from 1 RCT testing short-term use of famciclovir.
Long-term (> 1 month) use of oral antiviral agents reduced the recurrence of HSL. There was evidence from 1 RCT that long-term use of oral aciclovir reduced clinical recurrences (1.80 versus 0.85 episodes per participant per a 4-month period, P = 0.009) and virological recurrence (1.40 versus 0.40 episodes per participant per a 4-month period, P = 0.003). One RCT found long-term use of valaciclovir effective in reducing the incidence of HSL (with a decrease of 0.09 episodes per participant per month; n = 95). One RCT found that a long-term suppressive regimen of valaciclovir had a lower incidence of HSL than an episodic regimen of valciclovir (difference in means (MD) -0.10 episodes per participant per month, 95% CI -0.16 to -0.05; n = 120).
These trials found no increase in adverse events associated with the use of oral antiviral agents (moderate quality evidence).
There was no evidence to show that short-term use of topical antiviral agents prevented recurrent HSL.
Date of latest search: 2015-05-19