Most guidelines for pre-exposure prophylaxis of influenza in patients with cancer and on chemotherapy suffice with recommending vaccination. Some mention antiviral prophylaxis.
Patients with active malignant disease are at higher risk for upper respiratory tract infection due to influenza, parainfluenza or respiratory syncycial virus (RSV). Although response to vaccination with the attenuated influenza vaccine in patients on chemotherapy is highly variable, ranging from 24–75%, immunoprophylaxis with the influenza vaccine is recommended for patients with active malignant disease or chemotherapy. The same applies to patients with lymphoproliferative disease or multiple myeloma. In areas and seasons where influenza is endemic, chemoprophylaxis with neuraminidase inhibitors like tamiflu can be considered simultaneously to vaccination in exposed patients with a high risk of influenza complications.
The CDS writes that the duration of pre-exposure chemoprophylaxis based depends on the duration of community influenza activity. Regimens as long as 28 days for zanamivir, and 42 days for oseltamivir, have been well tolerated, but no published data are available regarding use of regimens lasting >6 weeks. The drug must be taken each day for the duration of influenza activity in the community.
M. Sandherr et al, Antiviral prophylaxis in patients with haematological malignancies and solid tumours: Guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Oncology (DGHO) Annals of Oncology 17: 1051–1059, 2006
Alastair Smith et al, Guidelines on the diagnosis and management of multiple myeloma 2005 British Journal of Haematology Volume 132, Issue 4, pages 410–451, February 2006
National Institute for Health and Clinical Excellence (NICE). Oseltamivir, amantadine (review) and zanamivir for the prophylaxis of influenza. London (UK): National Institute for Health and Clinical Excellence (NICE); 2008 Sep. 37 p. (Technology appraisal guidance; no. 158).
http://www.cdc.gov/flu/professionals/antivirals/antiviral-agents-flu.htm, 2012
Booy R, Lindley RI, Dwyer DE, Yin JK, Heron LG, Moffatt CR, Chiu CK, Rosewell AE, Dean AS, Dobbins T, Philp DJ, Gao Z, Macintyre CR. Treating and preventing influenza in aged care facilities: a cluster randomised controlled trial. PLoS One. 2012;7(10):e46509.