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J Infect. 2015 Feb;70(2):187-96. doi: 10.1016/j.jinf.2014.09.003. Epub 2014 Sep 16.

Hemagglutination inhibiting antibodies and protection against seasonal and pandemic influenza infection.

Author information

1
Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme, Viet Nam; Center for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK; The University of Melbourne, Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, Parkville, Victoria, Australia. Electronic address: afox@oucru.org.
2
National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam.
3
Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme, Viet Nam; Center for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
4
Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme, Viet Nam.
5
Ha Nam Centre for Preventive Medicine, Ha Nam, Viet Nam.
6
World Health Organization Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory, North Melbourne, Australia.

Abstract

OBJECTIVES:

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.

METHODS:

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.

RESULTS:

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 p < 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.

CONCLUSIONS:

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.

KEYWORDS:

Antibody; Hemagglutination inhibition tests; Human; Humans; Humoral; Immunity; Influenza; Neutralizing; Pandemics

PMID:
25224643
PMCID:
PMC4309889
DOI:
10.1016/j.jinf.2014.09.003
[Indexed for MEDLINE]
Free PMC Article

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