Skip directly to search Skip directly to A to Z list Skip directly to site content
CDC Home

Volume 17, Number 2—February 2011

Dispatch

Comparison of Pandemic (H1N1) 2009 and Seasonal Influenza Viral Loads, Singapore

Chun K. Lee, Hong K. Lee, Tze P. Loh, Florence Y.L. Lai, Paul A. Tambyah, Lily Chiu, Evelyn S.C. Koay, and Julian W. TangComments to Author 
Author affiliations: Author affiliations: National University Hospital, Singapore (C.K. Lee, H.K. Lee, T.P. Loh, P.A. Tambyah, L. Chiu, E.S.C. Koay, J.W. Tang); Ministry of Health, Singapore (F.Y.L. Lai); National University of Singapore, Singapore (P.A. Tambyah, E.S.C. Koay)

Main Article

Table 1

Comparison of baseline characteristics between patients with pandemic (H1N1) 2009 and seasonal influenza H3 infection, Singapore, May–November 2009

Characteristic Pandemic (H1N1) 2009, no. (%), n = 578 Seasonal influenza H3, no. (%), n = 77 p value
Age, y <0.0001
0–4 69 (11.9) 7 (9.1)
5–14 144 (24.9) 11 (14.3)
15–34 250 (43.3) 28 (36.4)
35–54 72 (12.5) 13 (16.9)
>55
43 (7.4)
18 (23.4)

Female sex
275 (47.6)
41 (53.2)
0.3959
Comorbidities* 262 (45.3) 22 (28.6) 0.0068
Asthma 120 (20.8) 7 (9.1) 0.0137
Chronic lung disease 15 (2.6) 3 (3.9) 0.4584
Cardiac disease 21 (3.6) 4 (5.2) 0.5214
Chronic renal failure 21 (3.6) 2 (2.6) 1.0000
Chronic liver disease 11 (1.9) 0 0.6275
Cerebrovascular disease 9 (1.6) 2 (2.6) 0.3776
Neoplasms 22 (3.8) 3 (3.9) 1.0000
Diabetes 41 (7.1) 5 (6.5) 1.0000
Pregnancy 39 (6.7) 2 (2.6) 0.2115
Immunocompromised 27 (4.7) 2 (2.6) 0.5621
Receipt of steroid medication 23 (4.0) 1 (1.3) 0.3429
Autoimmune disease 14 (2.4) 1 (1.3) 1.0000
Neurocognitive disease 12 (2.1) 1 (1.3) 1.0000
Neuromuscular disease
2 (0.3)
0
1.0000
Premitigation phase
104 (18.0)
51 (66.2)
<0.0001
Clinical severity† 0.0462
Severe cases‡ 23 (4.9) 1 (3.8)
Hospitalized cases§ 222 (46.8) 6 (23.1)
Outpatient only 229 (48.3) 19 (73.1)

*Patient had >1 of the conditions listed.
†Analysis was limited to patients in whom influenza were diagnosed during the mitigation phase (n = 474 for pandemic and n = 26 for H3 seasonal influenzas). Singapore switched from premitigation (i.e., containment) to mitigation management protocols on July 8, 2009, which altered how patient treatment with oseltamivir was initiated. However, this transition does not affect the results shown above because none of the patients were undergoing treatment when these first diagnostic samples were taken.
‡Patients requiring intensive or high-dependency care or who died.
§Patients requiring hospitalization because of clinical conditions but not intensive or high-dependency care.

Main Article

Top of Page

USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO