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Prevalence of antibodies to 2009 pandemic influenza A (H1N1) virus in German adult population in pre- and post-pandemic period.

Dudareva S, Schweiger B, Thamm M, Höhle M, Stark K, Krause G, Buda S, Haas W - PLoS ONE (2011)

Bottom Line: Proportions of samples with antibodies at titre ≥ 40 and geometric mean of the titres (GMT) were calculated and compared among 6 age groups (18-29, 30-39, 40-49, 50-59, 60-69, ≥ 70 years).The GMT increased between the pre- and post-pandemic period by a factor of 10.2 (95% CI 5.0-20.7) in the birth cohort born after 1976, 6.3 (95% CI 3.3-11.9) in those born between 1957 and 1976 and 2.4 (95% CI 1.3-4.3) in those born before 1957.We demonstrate that infection rates differed among age groups and that the measured pre-pandemic level of cross-reactive antibodies towards pH1N1 did not add information in relation to protection and prediction of the most affected age groups among adults in the pandemic.

View Article: PubMed Central - PubMed

Affiliation: European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden. DudarevaS@rki.de

ABSTRACT

Background: In order to detect levels of pre-existing cross-reactive antibodies in different age groups and to measure age-specific infection rates of the influenza A (H1N1) 2009 pandemic in Germany, we conducted a seroprevalence study based on samples from an ongoing nationwide representative health survey.

Methodology/principal findings: We analysed 845 pre-pandemic samples collected between 25 Nov 2008 and 28 Apr 2009 and 757 post-pandemic samples collected between 12 Jan 2010 and 24 Apr 2010. Reactive antibodies against 2009 pandemic influenza A (H1N1) virus (pH1N1) were detected using a haemagglutination inhibition test (antigen A/California/7/2009). Proportions of samples with antibodies at titre ≥ 40 and geometric mean of the titres (GMT) were calculated and compared among 6 age groups (18-29, 30-39, 40-49, 50-59, 60-69, ≥ 70 years). The highest proportions of cross-reactive antibodies at titre ≥ 40 before the pandemic were observed among 18-29 year olds, 12.5% (95% CI 7.3-19.5%). The highest increase in seroprevalence between pre- and post-pandemic was also observed among 18-29 year olds, 29.9% (95% CI 16.7-43.2%). Effects of sampling period (pre- and post-pandemic), age, sex, and prior influenza immunization on titre were investigated with Tobit regression analysis using three birth cohorts (after 1976, between 1957 and 1976, and before 1957). The GMT increased between the pre- and post-pandemic period by a factor of 10.2 (95% CI 5.0-20.7) in the birth cohort born after 1976, 6.3 (95% CI 3.3-11.9) in those born between 1957 and 1976 and 2.4 (95% CI 1.3-4.3) in those born before 1957.

Conclusions/significance: We demonstrate that infection rates differed among age groups and that the measured pre-pandemic level of cross-reactive antibodies towards pH1N1 did not add information in relation to protection and prediction of the most affected age groups among adults in the pandemic.

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Related in: MedlinePlus

GMT by age group in pre-pandemic and post-pandemic period.In the six age groups in the pre-pandemic sample the GMT ranged from 5.8 to 7.9. GMT in those aged 18 to 29 years (7.9) in comparison to those 30 years of age and older (5.9) was significantly higher. When comparing pre- and post-pandemic results, age groups 18–29, 30–39 and 40–49 had significant increase in GMT with highest increase in the age group 18–29 years.
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pone-0021340-g001: GMT by age group in pre-pandemic and post-pandemic period.In the six age groups in the pre-pandemic sample the GMT ranged from 5.8 to 7.9. GMT in those aged 18 to 29 years (7.9) in comparison to those 30 years of age and older (5.9) was significantly higher. When comparing pre- and post-pandemic results, age groups 18–29, 30–39 and 40–49 had significant increase in GMT with highest increase in the age group 18–29 years.

Mentions: In the pre-pandemic sample the measured antibody titres ranged from 10 to 640. The weighted overall GMT in pre-pandemic sample was 6.2 (95% CI 5.8–6.7). In the six age groups the GMT ranged from 5.8 to 7.9 as shown in Figure 1 and displayed in Table S2. GMT in those aged 18 to 29 years (7.9) in comparison to those 30 years of age and older (5.9) was significantly higher (Wilcoxon test, p <0.001).


Prevalence of antibodies to 2009 pandemic influenza A (H1N1) virus in German adult population in pre- and post-pandemic period.

Dudareva S, Schweiger B, Thamm M, Höhle M, Stark K, Krause G, Buda S, Haas W - PLoS ONE (2011)

GMT by age group in pre-pandemic and post-pandemic period.In the six age groups in the pre-pandemic sample the GMT ranged from 5.8 to 7.9. GMT in those aged 18 to 29 years (7.9) in comparison to those 30 years of age and older (5.9) was significantly higher. When comparing pre- and post-pandemic results, age groups 18–29, 30–39 and 40–49 had significant increase in GMT with highest increase in the age group 18–29 years.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3119048&req=5

pone-0021340-g001: GMT by age group in pre-pandemic and post-pandemic period.In the six age groups in the pre-pandemic sample the GMT ranged from 5.8 to 7.9. GMT in those aged 18 to 29 years (7.9) in comparison to those 30 years of age and older (5.9) was significantly higher. When comparing pre- and post-pandemic results, age groups 18–29, 30–39 and 40–49 had significant increase in GMT with highest increase in the age group 18–29 years.
Mentions: In the pre-pandemic sample the measured antibody titres ranged from 10 to 640. The weighted overall GMT in pre-pandemic sample was 6.2 (95% CI 5.8–6.7). In the six age groups the GMT ranged from 5.8 to 7.9 as shown in Figure 1 and displayed in Table S2. GMT in those aged 18 to 29 years (7.9) in comparison to those 30 years of age and older (5.9) was significantly higher (Wilcoxon test, p <0.001).

Bottom Line: Proportions of samples with antibodies at titre ≥ 40 and geometric mean of the titres (GMT) were calculated and compared among 6 age groups (18-29, 30-39, 40-49, 50-59, 60-69, ≥ 70 years).The GMT increased between the pre- and post-pandemic period by a factor of 10.2 (95% CI 5.0-20.7) in the birth cohort born after 1976, 6.3 (95% CI 3.3-11.9) in those born between 1957 and 1976 and 2.4 (95% CI 1.3-4.3) in those born before 1957.We demonstrate that infection rates differed among age groups and that the measured pre-pandemic level of cross-reactive antibodies towards pH1N1 did not add information in relation to protection and prediction of the most affected age groups among adults in the pandemic.

View Article: PubMed Central - PubMed

Affiliation: European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden. DudarevaS@rki.de

ABSTRACT

Background: In order to detect levels of pre-existing cross-reactive antibodies in different age groups and to measure age-specific infection rates of the influenza A (H1N1) 2009 pandemic in Germany, we conducted a seroprevalence study based on samples from an ongoing nationwide representative health survey.

Methodology/principal findings: We analysed 845 pre-pandemic samples collected between 25 Nov 2008 and 28 Apr 2009 and 757 post-pandemic samples collected between 12 Jan 2010 and 24 Apr 2010. Reactive antibodies against 2009 pandemic influenza A (H1N1) virus (pH1N1) were detected using a haemagglutination inhibition test (antigen A/California/7/2009). Proportions of samples with antibodies at titre ≥ 40 and geometric mean of the titres (GMT) were calculated and compared among 6 age groups (18-29, 30-39, 40-49, 50-59, 60-69, ≥ 70 years). The highest proportions of cross-reactive antibodies at titre ≥ 40 before the pandemic were observed among 18-29 year olds, 12.5% (95% CI 7.3-19.5%). The highest increase in seroprevalence between pre- and post-pandemic was also observed among 18-29 year olds, 29.9% (95% CI 16.7-43.2%). Effects of sampling period (pre- and post-pandemic), age, sex, and prior influenza immunization on titre were investigated with Tobit regression analysis using three birth cohorts (after 1976, between 1957 and 1976, and before 1957). The GMT increased between the pre- and post-pandemic period by a factor of 10.2 (95% CI 5.0-20.7) in the birth cohort born after 1976, 6.3 (95% CI 3.3-11.9) in those born between 1957 and 1976 and 2.4 (95% CI 1.3-4.3) in those born before 1957.

Conclusions/significance: We demonstrate that infection rates differed among age groups and that the measured pre-pandemic level of cross-reactive antibodies towards pH1N1 did not add information in relation to protection and prediction of the most affected age groups among adults in the pandemic.

Show MeSH
Related in: MedlinePlus