Two infants with recurrence of herpes simplex virus (HSV) encephalitis are
reported. Both patients developed HSV encephalitis during their neonatal pe
riod and were treated with iv acyclovir. Long-term oral acyclovir prophylax
is was given thereafter. At the age of 8 and 11 months respectively, both b
abies, while under oral acyclovir prophylaxis, presented a second episode o
f HSV encephalitis. An inadequate dose of suppressive oral acyclovir therap
y may be responsible for the recurrence of encephalitis in these two babies
. Conclusion: The present observations emphasise the need for very long fol
low-up of any infant who has suffered from neonatal herpes simplex virus en
cephalitis 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.