529. Experience with Seasonal Zanamivir Prophylaxis in Canadian Healthcare Workers and Other Adults: A Pilot Study
Session: Poster Session: Hospital-acquired and Transplant Infections
Friday, October 30, 2009: 12:00 AM
Room: Poster Hall A
Background: Antiviral prophylaxis is a potential strategy for protecting healthcare workers (HCWs) during influenza pandemics. To date, use of prophylaxis in healthy adults has been limited to 6 weeks (28 days for zanamivir). As part of a pilot study, we enrolled HCWs and other adults in a study of 13 to 18 weeks’ prophylaxis.
Methods: In October 2008, 64 healthy adults (59 HCW) were randomized to vaccine (N=22) or seasonal zanamivir prophylaxis (N=42). Vaccine (V) was provided in October. Prophylaxis (P) began at onset of influenza season. Illness and adverse events were reported weekly; adverse events were recorded daily during weeks 1 & 7. Adherence to prophylaxis was assessed by medication count and weekly self-report. Nasopharyngeal (NP) swabs were submitted and symptom diaries kept for episodes of acute respiratory illness (ARI).
Results: 4/64 participants (2P, 2V) withdrew before the onset of the influenza season. Of the 40 remaining randomized to P, 4 (10%) discontinued P at <13 weeks: 1 (wk 1) with nausea, vomiting, and headache; 1 (wk 1) with increased nasal congestion; 1 (wk 4) with joint pain; and 1 (wk 11) to join a different study. On average, 6.5 doses of P were used per week with 73% reporting 100% adherence and no change in adherence detected up to wk 18. The most common adverse events reported in week 1 of P were runny/stuffy nose (32%P vs. 23%V), headache (22%P vs. 16%V), cough (3%P vs. 21%V), and diarrhea (16%P and 4%V). P continues through week 18. 82 illness reports were made and 75 NP swabs submitted. 2 (10%) participants randomized to V developed flu A and 1 (2%) randomized to P developed flu B (p=0.22). 26 (40%) participants developed other viral ARI: 15 HCV 229E/NL63, 9 HCVOC43, 3 rhinovirus A, 2 RSV A. Participants worked on the first day of reported illness in 61/81 (75%) of cases; 38 felt well enough to work and 22 (27%) said they were either too busy to stay home or felt obliged to work.
Conclusion: 90% of participants took zanamivir prophylaxis for 18 weeks, with the majority reporting 100% adherence. There was no significant difference in influenza incidence in P and V groups. Most HCWs with viral ARI work during the first few days of illness.
Bjug Borgundvaag, MD, Brenda Coleman, PhD, Steven Drews, PhD2, Karen Green, MSc3, Jeffrey Kwong, MD4, Joanne M. Langley, MD, FSHEA5, Mark Loeb, MD, MSc6, Donald Low, MD, Allison McGeer, MD, FRCPC, Shelly McNeil, MD, Christine Moore, BSc, Matthew Muller, MD, PhD4, Andrew E. Simor, MD, FRCPC7, Danuta Skowronski, MD4, STOP-Flu Study Group, Leslie Vincent, MScN3 and  B. L. Coleman, None. 
A. McGeer,
GlaxoSmithKline Role(s): Investigator, Research Relationship, Speaker's Bureau, Received: Research Grant, Speaker Honorarium.
B. Borgundvaag, None..
S. Drews, None..
J. C. Kwong, None. 
J. Langley,
sanofi pasteur Role(s): Grant Investigator, Grant Investigator, Grant Investigator, Received: Research Grant, Research Support.
wyeth Role(s): Investigator, Other, co- investigator, Investigator, Other, co- investigator, Investigator, Other, co- investigator, Received: Research Support.
GSK Role(s): Investigator, Investigator, Investigator, Received: Research Support.
MedImmune Role(s): Investigator, Investigator, Investigator, Received: Research Grant.
M. Loeb, None..
D. Low, None..
S. McNeil, None..
C. Moore, None..
M. Muller, None..
A. Simor, None..
D. Skowronski, None..
L. Vincent, None..
K. Green, None., (1)Ontario Ministry of Health and Long Term Care, Etobicoke, ON, Canada, (2)Mount Sinai Hospital, Toronto, ON, Canada, (3)STOP-Flu Study, Mount Sinai Hospital, (4)Dalhousie University, Halifax, NS, Canada, (5)McMaster University, Hamilton, ON, Canada, (6)Sunnybrook Health Sciences Centre, Toronto, ON, Canada


B. Borgundvaag, None

B. Coleman, None

S. Drews, None

K. Green, None

J. Kwong, None

J. M. Langley, None

M. Loeb, None

D. Low, None

A. McGeer, None

S. McNeil, None

C. Moore, None

M. Muller, None

A. E. Simor, None

D. Skowronski, None

STOP-Flu Study Group, None

L. Vincent, None