Pandemic (H1N1) 2009 influenza spread through the Northern Territory, Australia, during June-August 2009. We performed 2 cross-sectional serologic surveys on specimens from Northern Territory residents, with 445 specimens obtained prepandemic and 1,689 specimens postpandemic. Antibody titers were determined by hemagglutination inhibition against reference virus A/California/7/2009 on serum samp...

Cases of a novel swine-origin influenza A(H3N2) variant (H3N2v) have recently been identified in the US, primarily among children. We estimated potential epidemic attack rates (ARs) based on age-specific estimates of sero-susceptibility and social interactions. A contact network model previously established for the Greater Vancouver Area (GVA), Canada was used to estimate average epidemic (infe...

A hemagglutination inhibition (HAI) assay to assess serum antibody responses following Norwalk virus (NV) infection was developed. HAI activity increased significantly in individuals experimentally infected with NV (n = 18) and correlated with antibody levels measured in a histo-blood group antigen (HBGA) blocking assay. Prechallenge HAI antibody levels also correlated with protection from the ...

We report the immunogenicity of trivalent influenza immunization in 29 pregnant women compared with 22 nonpregnant women. We obtained blood specimens on day 0 prior to 2011-2012 influenza vaccine administration and day 28 after immunization. Hemagglutination inhibition (HAI) geometric mean titers were similar before immunization but were significantly reduced by 40%-50% in pregnant women after ...

IKEDA, S., CHIBA, S., CHIBA, Y., NAKAO, T. and Fuuui, S. Epidemiological, Clinical and Serological Studies on Epidemic of Mumps in an Infant Nursery. Tohoku J. exp. Med., 1971, 105 (4), 327-337 •\ Epidemiological, clinical and serological studies on the epidemic mumps were carried out in 47 infants in Central Babies Home, Sapporo. Furthermore by utilizing fluorescent antibody tests the influenc...

A new enzyme immunoassay (Rubenostika; Organon Teknika, Turnhout, Belgium), a new latex agglutination test (Rubalex; Orion Diagnostica, Espoo, Finland), and three other accepted methods for the determination of rubella immunity were compared with a standard hemagglutination inhibition assay. Of 224 serum samples tested, 54 (24%) were nonreactive and 24 (11%) were low titered. All procedures wer...

PURPOSE For evaluating the immunogenicity of an influenza vaccine, the microneutralization (MN) test has a higher sensitivity and specificity as compared to the hemagglutination inhibition (HI) test. However, the MN test is more time consuming and is difficult to standardize. We performed the MN test to determine its usefulness as an alternative or complementary test to the HI test for evaluati...

We describe incidence and risk factors for pandemic (H1N1) 2009 virus infection in healthcare personnel during the June-September 2009 epidemic in Singapore. Personnel contributed 3 serologic samples during June-October 2009, with seroconversion defined as a ≥4-fold increase in hemagglutination inhibition titers to pandemic (H1N1) 2009. Of 531 participants, 35 showed evidence of seroconversion....

From February through May of 1999, 13 cases of Influenza A virus (FLUAV), type H1N1 were reported at a Department of Defense influenza surveillance sentinel site in Lima, Peru. Genetic and antigenic analysis by hemagglutination inhibition and direct nucleotide sequencing of the HA1 region of the hemagglutinin gene were performed on two isolates, A/Peru/1641/99 and A/Peru/1798/99. Both isolates ...

BACKGROUND Although it has been estimated that pandemic Influenza A H1N1/2009 has infected millions of people from April to October 2009, a more precise figure requires a worldwide large-scale diagnosis of the presence of Influenza A/H1N1/2009 antibodies within the population. Assays typically used to estimate antibody titers (hemagglutination inhibition and microneutralization) would require t...