Cytomegalovirus Control in Critical Care

Inclusion Criteria: * Total hospital stay of less than 7 days * CMV seropositive * Critical care stay of \>24 hours * Mechanically ventilated, anticipated to continue for \> 48 hours Exclusion Criteria: * Known Pregnancy or breast feeding * Expected to survive less than 48 hours * Confirmed immunosuppression * Known or suspected Human Immunodeficiency Virus infection * Known or suspected underlying immunodeficiency (organ transplantation including stem cell transplantation on immunosuppression, congenital immunodeficiency, in receipt of immunosuppressive medication e.g. azathioprine, methotrexate, tacrolimus, cyclosporine, sirolimus, cyclophosphamide within 30 days) * Corticosteroids: Prednisolone chronic administration may be used up to a dose of 10mg/day on average over the preceding 30 days, stress dose hydrocortisone (up to 400mg/day) may be used, topical steroids may be used, short duration of higher dose steroids for exacerbations of chronic obstructive pulmonary disease (COPD) up to 1mg/kg prednisolone or equivalent are permitted for up to 14 days * Receipt of chemotherapeutic agent within the last 6 months * Use of systemic antiviral medication other than oseltamivir within the last 7 days. * Intubated and mechanically ventilated secondary to brain injury alone.