Estimating Infection Rates through Intra-Individual Variation of Antibody Titers in an Influenza Pandemic

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K21488
• Project/Area Number (Other): 18H06409 (2018)
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund (2019); Single-year Grants (2018)
• Review Section: 0908:Society medicine, nursing, and related fields
• Research Institution: Osaka Institute of Public Health
• Principal Investigator: Ukai Tomohiko 地方独立行政法人 大阪健康安全基盤研究所, 公衆衛生部, 主任研究員 (80729195)
• Project Period (FY): 2018-08-24 – 2023-03-31
• Keywords: インフルエンザ / H1N1pdm / 赤血球凝集阻止抗体価 / 中和抗体価

Outline of Final Research Achievements

Using paired serum samples from 241 individuals collected in workplace health checkups in Osaka Prefecture between April to June in 2009 and 2010, we measured the hemagglutination inhibition (HI) titer and neutralizing titer against the influenza A H1N1 vaccine strain (Strain ①) and H1N1pdm strain (Strain ②) before and after the 2009 pandemic. The HI antibody positive rate for Strain ① based on 2009 sera was high, at 62%, and the neutralizing antibody positive rate was 49%. However, for Strain ②, the neutralizing antibody positive rate was low at 7%. The neutralizing antibody positive rate for Strain ② in 2010 increased to 22%, particularly those born after 1970 showed higher rates than those born earlier, demonstrating 46%. This trend was also reflected in the seroconversion rate, corroborating that younger adults were more susceptible to the pandemic virus.

Free Research Field

疫学

Academic Significance and Societal Importance of the Research Achievements

2009年と比較して、2010血清のA/California/7/2009（H1N1pdm株)に対する中和価陽性率は高くなり、特に1970年以降に出生した対象者で顕著であった。これは中和価陽転率とも相関し、若年成人ほどパンデミックウイルスに感染していたことが示唆された。パンデミック前後の血清抗体価を測定することは流行の実態を把握する上で重要であり、パンデミックの発生が予測された時点から公衆衛生、ウイルス学、臨床など各分野の専門家が協力して調査体制を構築することで、次の年の流行予測に生かすことができる。