Prevalence of Antibodies to 2009 Pandemic Influenza A (H1N1) Virus in German Adult Population in Pre- and Post-Pandemic Period
2011

Antibodies to 2009 Pandemic Influenza A (H1N1) in Germany

Sample size: 1602 publication 10 minutes Evidence: moderate

Author Information

Author(s): Dudareva Sandra, Schweiger Brunhilde, Thamm Michel, Höhle Michael, Stark Klaus, Krause Gérard, Buda Silke, Haas Walter

Primary Institution: Robert Koch Institute, Berlin, Germany

Hypothesis

What are the levels of pre-existing cross-reactive antibodies and age-specific infection rates of the 2009 pandemic influenza A (H1N1) in Germany?

Conclusion

Infection rates differed among age groups, and pre-pandemic levels of cross-reactive antibodies did not provide useful information for predicting the most affected age groups during the pandemic.

Supporting Evidence

  • The highest proportions of cross-reactive antibodies before the pandemic were observed among 18–29 year olds, at 12.5%.
  • The overall GMT in the pre-pandemic sample was 6.2, while in the post-pandemic sample it was 10.6.
  • The study found a significant increase in seroprevalence among younger age groups post-pandemic.

Takeaway

The study looked at blood samples from people in Germany to see how many had antibodies against the 2009 flu virus before and after the pandemic. They found that younger people had more antibodies than older people.

Methodology

The study analyzed 845 pre-pandemic and 757 post-pandemic serum samples using a haemagglutination inhibition test.

Potential Biases

Potential bias from using self-reported vaccination status for pre-pandemic samples.

Limitations

The study did not include children and may have underestimated vaccination rates due to reliance on vaccination cards for post-pandemic samples.

Participant Demographics

Median age was 54 years in the pre-pandemic sample and 47 years in the post-pandemic sample, with a male to female ratio of approximately 0.9.

Statistical Information

P-Value

p<0.001

Confidence Interval

95% CI 7.3–19.5%

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0021340

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