Glezen W P, Keitel W A, Taber L H, Piedra P A, Clover R D, Couch R B
Department of Microbiology and Immunology, Baylor College of Medicine, Houston, TX 77030-3498.
Am J Epidemiol. 1991 Feb 1;133(3):296-304. doi: 10.1093/oxfordjournals.aje.a115874.
Since influenza A/H1N1 viruses reappeared during the 1977-1978 season, this subtype has contributed 27% of 6,609 documented influenza infections of persons with acute respiratory disease presenting to clinics serving as surveillance sites of the Influenza Research Center in Houston for the 12-year period ending June 1989. Wide differences in the distribution of H1N1 viruses occurred by age group: more than 50% of H1N1 infections were detected among persons aged 10-34 years, compared with 28% for influenza A/H3N2 and 35% for influenza B. Over age 35 years, the contribution of H1N1 viruses dropped to only 4%, compared with 20% and 16% for influenza A/H3N2 and influenza B, respectively. When birth dates of persons with positive cultures were examined, it was found that most of the H1N1-positive persons were born after 1950. Concurrently, longitudinal studies of families and other adults under intensive surveillance for infection, including cultures of all respiratory illnesses and tests for serum antibody rise over the respiratory disease season, revealed appreciable infection rates for adults born before 1950. Furthermore, the annual peak of hospitalization of older persons with pneumonia and other acute respiratory illnesses was significantly correlated with the peak of H1N1 virus activity in 1978-1979, a year when H1N1 viruses were the only influenza viruses prevalent. These observations indicate that many persons infected with influenza A/H1N1 viruses that circulated from 1946 through 1953 have immunity which has persisted for more than 25 years but this immunity is not complete. Reinfection that may result in serious illness in older vulnerable adults does occur but with lower frequency than with influenza A/H3N2 infection. Currently prevalent H1N1 variants are antigenically different from those that circulated in the 1950s; however, older adults readily acquire immunity to these new variants--perhaps as a result of immunologic priming that occurred in childhood.
自甲型H1N1流感病毒在1977 - 1978年流感季节再次出现以来，在截至1989年6月的12年期间，该亚型在休斯敦流感研究中心作为监测点的诊所就诊的6609例有记录的急性呼吸道疾病患者流感感染病例中占27%。H1N1病毒的分布在不同年龄组中存在很大差异：10 - 34岁人群中检测到的H1N1感染病例超过50%，相比之下，甲型H3N2流感为28%，乙型流感为35%。35岁以上人群中，H1N1病毒的占比降至仅4%，而甲型H3N2流感和乙型流感分别为20%和16%。检查培养结果呈阳性者的出生日期时发现，大多数H1N1阳性者出生于1950年之后。同时，对接受密切感染监测的家庭及其他成年人进行的纵向研究，包括对所有呼吸道疾病进行培养以及在呼吸道疾病季节检测血清抗体升高情况，结果显示1950年以前出生成年人的感染率相当可观。此外，1978 - 1979年，老年人因肺炎和其他急性呼吸道疾病住院的年度高峰与H1N1病毒活动高峰显著相关，在这一年H1N1病毒是唯一流行的流感病毒。这些观察结果表明，许多感染了1946年至1953年流行的甲型H1N1流感病毒的人具有持续超过25年的免疫力，但这种免疫力并不完全。可能导致老年易感成年人患重病的再次感染确实会发生，但频率低于甲型H3N2流感感染。目前流行的H1N1变异株在抗原性上与20世纪50年代流行的毒株不同；然而，老年人很容易获得针对这些新变异株的免疫力——这可能是童年时期发生的免疫启动的结果。
