Cytomegalovirus reactivations in the critically ill

Cytomegalovirus (CMV) reactivation is a well-recognised
complication of solid organ and stem cell transplantation,
causing both direct cytopathology in various organs and indirect
immunomodulating effects. However, reactivation also occurs in
14-71% of previously immunocompetent critically ill adults, and
although final proof of pathogenicity in such patients is lacking, many
studies show that it is independently associated with prolonged
mechanical ventilation and death. Two recent RCTs indicated
that both valganciclovir and ganciclovir are safe and effective in
preventing CMV reactivation in plasma, yet were underpowered
to detect meaningful clinical benefit. A much larger trial taking a
preemptive approach is expected to report shortly. Thus, based
on the available evidence, routine use of anti-CMV prophylaxis
in ICU patients who were previously immunocompetent cannot
be recommended at this time. However, in patients undergoing
a prolonged ICU stay, viral diagnostics and treatment of CMV
reactivation may be considered in cases of refractory ARDS or
otherwise unexplained organ failure.