RESUMO
<p><b>OBJECTIVE</b>To understand the infection condition and analytical methods of Influenza A (H1N1) virus in the population of Hunan Province during different periods.</p><p><b>METHODS</b>Quick surveys on the positive rate of Influenza A (H1N1) virus hemagglutination inhibition (HI) test have been conducted for 5 times successively from November 2009 to March 2010 in 14 medical and health institutions of Changsha city, whose results were then compared with those from the sampling surveys of whole Hunan province.</p><p><b>RESULTS</b>2131 subjects were involved in this study; the total population standardized rates of antibody positive investigated for 5 times were 9.32% , 14.62%, 31.08%, 28.43% and 22.80% respectively; the population of 6-17-years-old has the highest rate of antibody positive; only 9.84% of the antibody positive subjects attributed to vaccine inoculation; there was no significant difference in the standardized positive rates between the quick serological surveys and the corresponding sampling survey of Hunan province (P > 0.05).</p><p><b>CONCLUSION</b>The positive rate of A (H1N1) virus antibody reached the peak in late January 2010; quick investigations in small region could be used to evaluate the infection prevalence during pandemic of infectious diseases.</p>