An influenza A/H3 outbreak during the 2004/2005 winter in elderly vaccinated people living in a nursing home

Department of Hygiene, University of Perugia, Via del Giochetto, I-06100 Perugia, Italy.
Vaccine (Impact Factor: 3.62). 12/2006; 24(44-46):6615-9. DOI: 10.1016/j.vaccine.2006.05.037
Source: PubMed


This study examined the antibody response against the three vaccine antigens and the epidemic A/H3N2 drift variant (A/California) and the prevention of laboratory diagnosed influenza infections in a group of elderly institutionalized people vaccinated with the 2004/2005 influenza vaccine. Antibody titres were measured by hemagglutination inhibition (HI) in sera collected before and 1 month after vaccination. Laboratory diagnosis was done examining throat swabs (RT-PCR or MDCK cell culture) or by serology (seroconversion comparing HI titres in sera collected 1 and 5 months after vaccination). Results obtained showed that influenza vaccination induced an adequate immune response against the three vaccine antigens and the epidemic A/H3N2 variant, however it was not capable of preventing an influenza outbreak due to the new A/H3N2 (A/California) variant.

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Available from: Michela Basileo
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    • "We observed that subjects who received TIV in the previous year (′04-T group) had significantly higher baseline HAI for H3N2 A/California compared to those who received LAIV (′04-L group) or no vaccination (′04-N group) in the prior year (Figure 1A). Although the A/California used in the HAI assay is antigenically dissimilar to A/Wyoming in the vaccine of the previous year, some antibodies induced by A/Wyoming likely cross-react with A/California [42] and contribute to the protection against the latter [41]. This higher baseline HAI for A/California is likely to reflect the long lasting antibody response induced by TIV in 2004. "
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