[Nosocomial outbreak of influenza in high-risk hematological patients. Efficacy of control measures and the use of zanamivir].
BACKGROUND
This study describes a nosocomial outbreak of influenza in high-risk-hematological patients, and the usefulness of epidemiological measures and zanamivir administration for its control.


METHODS
Fifteen patients who had been in contact with a patient with influenza A were included in the study. Viral culture of nasopharyngeal exudate was performed and the epidemiological data, risk factors and clinical outcome were evaluated. The efficacy of early therapy and preventive use of zanamivir was also assessed.


RESULTS
Seven out of 15 patients (46.6%) developed symptoms and in 5 of these 7 cases (71.4%), influenza A virus was isolated. Eight patients did not develop symptoms and viral culture was sterile. All symptomatic patients were isolated, and treatment with inhaled zanamivir (10 mg/12 h, 5 days) was initiated as soon as possible; only one patient developed respiratory failure; the remaining cases had self-limited upper respiratory tract symptoms. There was no associated mortality. Zanamivir prophylaxis was used in three non-symptomatic patients considered to be at high risk. Tolerance to zanamivir was excellent. No new cases were observed after initiation of the preventive measures and use of zanamivir.


CONCLUSIONS
The attack rate in a nosocomial influenza outbreak can be very high in immunocompromised patients. Prompt initiation of preventive measures, early treatment and prophylaxis with zanamivir may help to limit the extension of these outbreaks.
Díaz-Pedrochea
Carmen
C
Unidad de Enfermedades Infecciosas, Hospital Universitario 12 de Octubre, Madrid, Spain. carmendiaz@ya.com
Lizasoain
Manuel
M
López-Medrano
Francisco
F
Escalante
Fernando
F
Lumbreras
Carlos
C
Folgueira
Dolores
D
Sanz-Gallardo
Inmaculada
I
Grande
Carlos
C
Aguado
José María
JM
D000998:Antiviral Agents / Q000627:therapeutic use*; D003428:Cross Infection / Q000188:drug therapy* / Q000517:prevention & control; D006146:Guanidines / Q000627:therapeutic use*; D019337:Hematologic Neoplasms / Q000276:immunology*; D006801:Humans; D016867:Immunocompromised Host; D017053:Infection Control; D009980:Influenza A virus; D007251:Influenza, Human / Q000188:drug therapy* / Q000517:prevention & control; D011714:Pyrans / Q000627:therapeutic use*; D012307:Risk Factors; D012794:Sialic Acids / Q000627:therapeutic use*; D053243:Zanamivir
D000998:Antiviral Agents; D006146:Guanidines; D011714:Pyrans; D012794:Sialic Acids; D053243:Zanamivir