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2007 Respiratory Viruses in Immunosuppressed Patients Policy (63 kB) |
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Page updated 30 April 2007
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Although common colds and upper respiratory illnesses may seem trivial, the viruses involved can cause life-threatening infection in immunocompromised patients |
Young children and immunosuppressed patients are susceptible to serious disease due to respiratory viruses such as influenza, parainfluenza and respiratory syncytial viruses (RSV).
Parainfluenza 3 virus causes annual outbreaks in the summer and influenza and RSV in the winter. In adults, they cause mild self-limiting upper respiratory tract illness. Infected infants may develop croup, bronchiolitis or pneumonia. Immunosuppressed patients may develop pneumonitis with any of these viruses. Bone marrow or peripheral stem cell recipients are at particularly high risk. Outbreaks have been reported with high mortality. Those most at risk are within four months of the transplant. The incubation period is 2-5 days.
Patients are infectious while they are symptomatic. Immunosuppressed patients may excrete virus for weeks or months.
Parainfluenza and RSV are transferred by direct or indirect contact. Aerosol droplet transmission is also possible, and is normal for influenza virus. The viruses are acquired on the hands by contact with respiratory secretions of the infected patient or their fomites. The organisms survive for many hours on environmental surfaces. Infection is most likely to be acquired when contamination from hands is inoculated into the mucosal surfaces of the nose and the eyes.
Diagnosis is best made by identifying the virus by immunofluorescence of respiratoy tract cells using specific antibodies. It is vital to send good specimens from the respiratory tract as soon as possible after symptoms start. This allows infection control procedures to be put in place. Culture may be done but is rather slow.
The best samples are:
Ribavirin is the only antiviral agent recommended for RSV infection. Combination of ribavirin and high titre immunoglobulin may be tried in immunosuppressed patients and may reduce mortality. Immunoglobulin may afford some protection in children against severe lower respiratory tract infection. There are no data to suggest that ribavirin is active against parainfluenza virus infection.
The Occupational Health staff at most hospitals now offer immunisation to all staff in the autumn. The aim is to reduce sickness levels in staff during the winter 'flu season. It is particularly important for those working in critical areas (eg intensive care, A/E, obstetrics, infectious diseases). Epidemics of influenza cannot be predicted. The vaccine contains representatives of strains which have been seen in the last few years. A major antigenic shift in the type of virus would render the vaccine ineffective. Viruses for vaccines are raised in hen's eggs, so the vaccine is contraindicated in those with egg allergy. The vaccine is also offered to the old and infirm.
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