Two infants with recurrence of herpes simplex virus (HSV) encephalitis are reported. Both patients developed HSV encephalitis during their neonatal period and were treated with iv acyclovir. Long-term oral acyclovir prophylaxis was given thereafter. At the age of 8 and 11 months respectively, both babies, while under oral acyclovir prophylaxis, presented a second episode of HSV encephalitis. An inadequate dose of suppressive oral acyclovir therapy may be responsible for the recurrence of encephalitis in these two babies.
Conclusion: The present observations emphasise the need for very long follow-up of any infant who has suffered from neonatal herpes simplex virus encephalitis and the need for careful prospective controlled studies in order to define the appropriate treatment regimen (initial plus prophylaxis) for neonates with herpes simplex virus infections.