Epidemiological and Virological Assessment of Influenza Activity in Apulia, Italy, during the Seasons 2004–2005 and 2005–2006

Surveillance of human influenza A(H3N2) virus from 1999 to 2009 in southern Italy

The aim of this study was to evaluate the presence of influenza virus co-infections in humans and changes in the genetic variability of A(H3N2) virus strains in southern Italy from 1999 to 2009. A partial sequence of the haemagglutinin (HA) gene by human influenza H3N2 strains identified in oropharyngeal swabs from patients with influenza-like illness was analysed by DNA sequencing and a phylogenetic analysis was performed. During the seasons 1999-2000, 2002-2003, 2004-2005 and 2008-2009, the influenza viruses circulating belonged to subtype H3N2. However, A(H1N1) subtype virus and B type were respectively prevalent during the 2000-2001, 2006-2007, 2007-2008 and 2001-2002, 2003-2004, 2005-2006 seasons. The HA sequences appeared to be closely related to the sequence of the influenza A vaccine strain. Only the 2002-2003 season was characterized by co-circulation of two viral lineages: A/New York/55/01(H3N2)-like virus of the previous season and A/Fujian/411/02(H3N2)-like virus, a new H3 variant. In this study, over the decade analysed, no significant change was seen in the sequences of the HA gene of H3 viruses isolated.

Evaluation of immune responses to seasonal influenza vaccination in healthy volunteers in South Apulia, Italy: a pilot study

BACKGROUND

The aim of our pilot study is to investigate different components of the immune response to influenza vaccination in a group of healthy volunteers. We evaluated the cellular immune response (CD4(+) T lymphocytes) by flow cytometry. The humoral immune response was assessed by measuring the serum haemagglutination inhibition antibody response.

METHODS

Healthy adult donors (n = 18), were vaccinated with a commercially influenza virus vaccine (FLUARIX® GlaxoSmithKline S.p.a. Verona, Italy), peripheral blood was drawn the same day as influenza virus vaccination and one month later in order to enumerate the antigen-specific CD4(+) T lymphocytes. Hemagglutination inhibition assay was performed to enumerate the titer of neutralizing antibodies. Samples of nasal-pharyngeal secretions were taken by swabbing, from ILI (Influenza like Illness) subjects among the studied group, in order to verify influenza infections and eventually identify viruses using Real Time PCR.

RESULTS AND CONCLUSIONS

Parenteral influenza vaccination results in significant increase in the CD4(+) Th cell population after vaccination. The number of pre-vaccination CD4(+) T cells was 0.018 [the results are presented as number of percent fluorescent cells per 10 000 lymphocytes (fixed cells)], while there was a significantly higher number of CD4(+) Th cells one month after vaccination (statistical significance was set at the level of α = 0.01). Twenty-two percent of patients demonstrated protective antibody levels to influenza A H1/N1 serotype. None was diagnosed with influenza type A or B.

KEYWORDS

T cells; Flow cytometry; Influenza virus; Influenza vaccine.

Ten-year (1999-2009) epidemiological and virological surveillance of influenza in South Italy (Apulia)

Clinical and epidemiological surveillance of influenza and other Acute Respiratory Infections (ARI) are currently a major objective of Public Health. The aim was to describe the epidemiology of influenza using the Italian surveillance system. Vaccination Coverage (VC) rates were calculated during 1999-2009 influenza seasons. Molecular studies of influenza virus isolated, from patients with ILI, living in Apulia, are described. 1269 nasal-pharyngeal swabs were taken from patients with ILI and ARI in order to isolate and identify viruses using PCR. Influenza isolates are typed as being types A and B and influenza A isolates are A/H1 and A/H3. The progression of the ILI cases registered in Apulia was similar to the data recorded on a national level. The VC data recorded in Apulia showed a progressive increase in the vaccine doses administered to subjects over 65 years old. The virological surveillance showed a major circulation of the type A/H3N2 influenza virus during the peak incidence of the illness in seasons 1999-2000, 2002-2003, 2004-2005 and 2008-2009. During the same period, the lowest incidence was registered when the type A/H1N1 and B viruses were in circulation. In contrast, during the other seasons the lowest incidence was reported with A/H3N2 and B viruses.