BACKGROUND 2009 pandemic influenza A/H1N1 (A(H1N1)pdm09) was first detected in the United States in April 2009 and resulted in a global pandemic. We conducted a serologic survey to estimate the cumulative incidence of A(H1N1)pdm09 through the end of 2009 when pandemic activity had waned in the United States. METHODS We conducted a pair of cross sectional serologic surveys before and after the...

Influenza viruses undergo continual antigenic evolution allowing mutant viruses to evade host immunity acquired to previous virus strains. Antigenic phenotype is often assessed through pairwise measurement of cross-reactivity between influenza strains using the hemagglutination inhibition (HI) assay. Here, we extend previous approaches to antigenic cartography, and simultaneously characterize a...

Inactivated influenza vaccination induces a hemagglutinin-specific antibody response to the strain used for immunization. Annual vaccination is strongly recommended for health care personnel. However, it is debatable if repeated vaccination would affect the antibody response to inactivated influenza vaccine through the time. We enrolled health care personnel who had repeated and first trivalent...

An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the detection of IgG serum antibodies to swine Sendai virus. To evaluate the preliminary potential of ELISA, sera from 10 healthy pigs and 34 sera from finishing pigs suffering from respiratory signs were tested. The results were compared with those obtained from the same sera by hemagglutination inhibition assay.

For accurate quantitation of human immunoglobulins A and B by graded hemagglutination inhibition, I have established standard curves. For IgA, plotting the inner diameter of the ring formed by sedimented erythrocytes vs the log of the antigen concentrations gives a straight line. Plotting the same parameters for IgG gives a hyperbolic line. These ratios between antigen concentration and ring di...

BACKGROUND During the influenza pandemic of 2009/10, the whole-virion, Vero-cell-derived, inactivated, pandemic influenza A (H1N1) vaccine Celvapan® (Baxter) was used in Austria. Celvapan® is adjuvant-free and was the only such vaccine at that time in Europe. The objective of this observational, non-interventional, prospective single-center study was to evaluate the immunogenicity and tolerabil...

This study aimed to measure the prevalence of antibodies to arboviruses in the area affected by the Juruti Project before local mining operations. A total of 1,597 human and 85 wild animal sera were examined, using the hemagglutination inhibition test against 19 antigens from the most prevalent arboviruses in the Brazilian Amazon and IgM-ELISA for dengue and yellow fever. Positive sera for Maya...

BACKGROUND The direct effect of antigenic site mutations in influenza viruses on antigenic drift and vaccine effectiveness is poorly understood. OBJECTIVE To investigate the genetic and antigenic characteristics of human influenza A (H3N2) viruses circulating in Ontario during the early 2010-2011 winter season. STUDY DESIGN We sequenced the hemagglutinin (HA) and neuraminidase (NA) genes fr...

The passive administration of ferret antiserum to Ao (H0N1) influenza virus failed to protect the recipient ferrets from subsequent infection with homologous virus. This susceptibility to infection was observed even when the passively acquired serum hemagglutination inhibition (HI) titer was similar to peak convalescent titers. It is therefore concluded that serum antibody alone is probably not...

In an effort to understand the unusual cytogenetic damage earlier encountered in the Yanomama Indians, plasma samples from 425 Amerindians representing 14 tribes have been tested for hemagglutination inhibition antibodies to the human JC polyoma virus and from 369 Amerinds from 13 tribes for hemagglutination inhibition antibodies to the human BK polyoma virus. There is for both viruses highly s...