Tweet
J Infect Dis. 2018 May 12. doi: 10.1093/infdis/jiy291. [Epub ahead of print]
Population Serologic Immunity to human and avian H2N2 viruses in the United States and Hong Kong for Pandemic Risk Assessment.
Babu TM1, Perera R2, Wu JT2, Fitzgerald T1, Nolan C1, Cowling BJ2, Krauss S3, Treanor JT1, Peiris M2.
Author information
Abstract
Introduction:
Influenza A pandemics cause significant mortality and morbidity. H2N2 viruses have caused prior pandemic, and are circulating in avian reservoirs. The age-related frequency of current population immunity to H2 viruses was evaluated.
Methods:
Hemagglutinin inhibition (HAI) assays against historical human and recent avian influenza A (H2N2) viruses were performed across age groups in Rochester, NY and Hong Kong, China. The impact of existing cross-reactive HAI immunity on the effective reproductive number(R) was modeled.
Results:
150 individual sera from Rochester and 295 from Hong Kong were included. 85% born in Rochester and Hong Kong before 1968 had HAI titers >1:40 against A/Singapore/1/57, and over 50% had titers >1:40 against A/Berkeley/1/68. The frequency of titers ≥1:40 to avian H2N2 A/Mallard/England/727/06 and A/Mallard/Netherlands/14/07 in subjects born before 1957 was 62% and 24%. There were no H2 HAI titers >1:40 in individuals born after 1968. These levels of seroprevalence reduce the initial R of A/Singapore/1/1957 or A/Berkeley/1/68 by 15%-20%. A basic reproductive number (R0) of the emerging transmissible virus less than 1.2 predicts a preventable pandemic.
Conclusions:
Population immunity to H2 viruses is insufficient to block epidemic spread of H2 virus. An H2N2 pandemic would have lower impact in those born before 1968.
PMID: 29762672 DOI: 10.1093/infdis/jiy291
Population Serologic Immunity to human and avian H2N2 viruses in the United States and Hong Kong for Pandemic Risk Assessment.
Babu TM1, Perera R2, Wu JT2, Fitzgerald T1, Nolan C1, Cowling BJ2, Krauss S3, Treanor JT1, Peiris M2.
Author information
Abstract
Introduction:
Influenza A pandemics cause significant mortality and morbidity. H2N2 viruses have caused prior pandemic, and are circulating in avian reservoirs. The age-related frequency of current population immunity to H2 viruses was evaluated.
Methods:
Hemagglutinin inhibition (HAI) assays against historical human and recent avian influenza A (H2N2) viruses were performed across age groups in Rochester, NY and Hong Kong, China. The impact of existing cross-reactive HAI immunity on the effective reproductive number(R) was modeled.
Results:
150 individual sera from Rochester and 295 from Hong Kong were included. 85% born in Rochester and Hong Kong before 1968 had HAI titers >1:40 against A/Singapore/1/57, and over 50% had titers >1:40 against A/Berkeley/1/68. The frequency of titers ≥1:40 to avian H2N2 A/Mallard/England/727/06 and A/Mallard/Netherlands/14/07 in subjects born before 1957 was 62% and 24%. There were no H2 HAI titers >1:40 in individuals born after 1968. These levels of seroprevalence reduce the initial R of A/Singapore/1/1957 or A/Berkeley/1/68 by 15%-20%. A basic reproductive number (R0) of the emerging transmissible virus less than 1.2 predicts a preventable pandemic.
Conclusions:
Population immunity to H2 viruses is insufficient to block epidemic spread of H2 virus. An H2N2 pandemic would have lower impact in those born before 1968.
PMID: 29762672 DOI: 10.1093/infdis/jiy291