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Influenza Other Respir Viruses. 2018 Dec 9. doi: 10.1111/irv.12623. [Epub ahead of print]
Antibody levels in a cohort of pregnant women after the 2009 influenza A(H1N1) pandemic: waning and association with self-reported severity and duration of illness.
Tunheim G1,2, Laake I1, Robertson AH1, Waalen K1, Hungnes O1, Naess LM1, Cox RJ2,3,4, Mjaaland S1,2, Trogstad L1.
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Abstract
BACKGROUND:
A population-based pregnancy cohort was established in Norway to study potential effects of exposure to the 2009 influenza pandemic or pandemic vaccination during pregnancy.
OBJECTIVES:
We studied maternal A(H1N1)pdm09-specific hemagglutination inhibition (HI)-titer levels and waning in women with influenza-like illness (ILI) in pregnancy compared to vaccinated women. Moreover, we studied the association between HI-titers and self-reported severity and duration of ILI.
METHODS:
HI-titers against the pandemic virus were measured in maternal blood samples obtained at birth, 3-9 months after exposure, and linked with information about pregnancy, influenza and vaccination from national registries and a cohort questionnaire.
RESULTS:
Among 1821 pregnant women included, 43.7% were unvaccinated and 19.3% of these had ILI. HI-titers were low (geometric mean titer (GMT) 11.3) in the unvaccinated women with ILI. Higher HI-titers (GMT 37.8) were measured in the vaccinated women. Estimated HI-titer waning was similar for vaccinated women and women with ILI. Most ILI episodes were moderate and lasted 3-5 days. Women with ILI reporting specific influenza symptoms such as fever or cough had higher HI-titers than women without these symptoms. Women who reported being "very ill" or illness duration of >5 days, had higher HI-titers than women reporting less severe illness or illness of shorter duration, respectively.
CONCLUSIONS:
Antibody waning was similar in vaccinated women and women with ILI. More severe ILI or longer duration of illness were associated with higher HI-titers. Most unvaccinated pregnant women with ILI had low HI-titers, probably due to moderate illness and HI-titer waning between exposure and sampling. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
KEYWORDS:
antibodies; influenza; pandemic H1N1pdm09; pregnancy; vaccination; waning
PMID: 30536590 DOI: 10.1111/irv.12623
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Antibody levels in a cohort of pregnant women after the 2009 influenza A(H1N1) pandemic: waning and association with self-reported severity and duration of illness.
Tunheim G1,2, Laake I1, Robertson AH1, Waalen K1, Hungnes O1, Naess LM1, Cox RJ2,3,4, Mjaaland S1,2, Trogstad L1.
Author information
Abstract
BACKGROUND:
A population-based pregnancy cohort was established in Norway to study potential effects of exposure to the 2009 influenza pandemic or pandemic vaccination during pregnancy.
OBJECTIVES:
We studied maternal A(H1N1)pdm09-specific hemagglutination inhibition (HI)-titer levels and waning in women with influenza-like illness (ILI) in pregnancy compared to vaccinated women. Moreover, we studied the association between HI-titers and self-reported severity and duration of ILI.
METHODS:
HI-titers against the pandemic virus were measured in maternal blood samples obtained at birth, 3-9 months after exposure, and linked with information about pregnancy, influenza and vaccination from national registries and a cohort questionnaire.
RESULTS:
Among 1821 pregnant women included, 43.7% were unvaccinated and 19.3% of these had ILI. HI-titers were low (geometric mean titer (GMT) 11.3) in the unvaccinated women with ILI. Higher HI-titers (GMT 37.8) were measured in the vaccinated women. Estimated HI-titer waning was similar for vaccinated women and women with ILI. Most ILI episodes were moderate and lasted 3-5 days. Women with ILI reporting specific influenza symptoms such as fever or cough had higher HI-titers than women without these symptoms. Women who reported being "very ill" or illness duration of >5 days, had higher HI-titers than women reporting less severe illness or illness of shorter duration, respectively.
CONCLUSIONS:
Antibody waning was similar in vaccinated women and women with ILI. More severe ILI or longer duration of illness were associated with higher HI-titers. Most unvaccinated pregnant women with ILI had low HI-titers, probably due to moderate illness and HI-titer waning between exposure and sampling. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
KEYWORDS:
antibodies; influenza; pandemic H1N1pdm09; pregnancy; vaccination; waning
PMID: 30536590 DOI: 10.1111/irv.12623
Free full text