Hemagglutination inhibiting antibodies and protection against seasonal and pandemic influenza infection. Issue 2 (February 2015)

• Record Type: Journal Article
• Authors: Fox, Annette; Mai, Le Quynh; Thanh, Le Thi; Wolbers, Marcel; Le Khanh Hang, Nguyen; Thai, Pham Quang; Thu Yen, Nguyen Thi; Minh Hoa, Le Nguyen; Bryant, Juliet E.; Duong, Tran Nhu; Thoang, Dang Dinh; Barr, Ian G.; Wertheim, Heiman; Farrar, Jeremy; Hien, Nguyen Tran; Horby, Peter
• Is Part Of: Journal of infection. Volume 70:Issue 2(2015)
• Page Start: 187
• Page End: 196
• Publication Date: 2015-02
• Subjects: Infection -- Periodicals; Bacterial Infections -- Periodicals; Communicable Diseases -- Periodicals; Electronic journals; 616.905
• DOI: 10.1016/j.jinf.2014.09.003
• Languages: English
• ISSNs: 0163-4453

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Summary</title> <sec> <title id="sectitle0015">Objectives</title> <p id="abspara0010">Hemagglutination inhibiting (HI) antibodies correlate with influenza vaccine protection but their association with protection induced by natural infection has received less attention and was studied here.</p> </sec> <sec> <title id="sectitle0020">Methods</title> <p id="abspara0015">940 people from 270 unvaccinated households participated in active ILI surveillance spanning 3 influenza seasons. At least 494 provided paired blood samples spanning each season. Influenza infection was confirmed by RT-PCR on nose/throat swabs or serum HI assay conversion.</p> </sec> <sec> <title id="sectitle0025">Results</title> <p id="abspara0020">Pre-season homologous HI titer was associated with a significantly reduced risk of infection for H3N2 (OR 0.61, 95%CI 0.44–0.84) and B (0.65, 95%CI 0.54–0.80) strains, but not H1N1 strains, whether re-circulated (OR 0.90, 95%CI 0.71–1.15), new seasonal (OR 0.86, 95%CI 0.54–1.36) or pandemic H1N1-2009 (OR 0.77, 95%CI 0.40–1.49). The risk of seasonal and pandemic H1N1 decreased with increasing age (both <italic>p</italic> < 0.0001), and the risk of pandemic H1N1 decreased with prior seasonal H1N1 (OR 0.23, 95%CI 0.08–0.62) without inducing measurable A/California/04/2009-like titers.</p> </sec> <sec> <title id="sectitle0030">Conclusions</title> <p id="abspara0025">While H1N1 immunity was apparent with increasing age and prior infection, the effect of pre-season HI titer was at best small, and weak for H1N1 compared to H3N2 and B. Antibodies targeting non-HI epitopes may have been more important mediators of infection-neutralizing immunity for H1N1 compared to other subtypes in this setting.</p> </sec> </abstract>