OBJECTIVEAnalyze the clinical characteristics of the mild cases of pandemic influenza H1N1 virus infection, as well as the relationship of clinical characteristics and patient genders.

METHODSA total of 245 influenza A (H1N1) patients confirmed by viral nucleic acid detection were included in the study. The patients' personal information, signs and symptoms, lab and iconography data, disease course, negative seroconversion duration of new influenza A (H1N1) viral nucleic acid after antiviral treatment and hospitalization stay were analyzed. Measurement data were analyzed using one-way analysis of variance (ANOVA) by software SPSS 11.5. P < 0.05 was defined as statistically significant.

RESULTS(1) Among the 245 patients, 130 were males and 115 were females, yielding a sex ratio of 1.13:1. Almost 52.0% (127/245) of the patients came from Australia, and 64.5% (158/245) were between 18 and 40 years old. (2) Clinical manifestations included fever (98.4%, 241/245), cough (80.8%, 198/245) and throat congestion (95.9%, 235/245), and lab findings were characterized by elevated C-reaction protein (CRP, 71.0%, 174/245) and neutrophil (52.2%, 128/245). (3) Female patients had significantly lower serum Prealbumin (pre-A) levels than male patients [(245.04 ± 75.3) vs (273.34 ± 92.18) mg/L, F = 5.55, P = 0.019]. (4) The patients' serum CRF levels significantly decreased after the treatment [(4.06 ± 3.47) vs (14.54 ± 14.68) mg/L, F = 6.18, P = 0.016], while the levels of CD3, CD4 and CD8 were significantly increased after treatment [(1451.23 ± 443.97) vs (819.97 ± 375.75) cell/µl, F = 32.61, P = 0.000; (771.33 ± 251.92) vs (435.36 ± 215.35) cell/µl, F = 44.43, P = 0.000; (593.16 ± 237.19) vs (342.47 ± 180.12) cell/µl, F = 28.518, P = 0.000, respectively]. (5) Approximately 30.6% (75/245) of the patients had abnormal signs on chest CT iconography, and 22.0% (54/245) had obvious signs indicating pneumonia. The average disease course was (3.9 ± 1.2) days, the average hospitalization stay was (5.0 ± 1.4) days, and the negative seroconversion duration of the mRNA after antiviral treatment was (3.8 ± 1.4) days.

CONCLUSIONThe influenza A (H1N1) virus was characterized by fever, cough and throat congestion, with elevated CRP and neutrophil being the most significant lab findings. The influenza A (H1N1) strain was able to affect multiple organs, including being able to affect hepatic synthesis of pre-A as well as immune functioning. The influenza A (H1N1) influenza virus strain was mild clinically, with short disease course and good prognosis.