Post by Nadica (She/Her) on Jul 14, 2024 23:40:36 GMT
Avian Influenza A(H5N1) Neuraminidase Inhibition Antibodies in Healthy Adults after Exposure to Influenza A(H1N1)pdm09 - Published Dec 18, 2023
Abstract
We detected high titers of cross-reactive neuraminidase inhibition antibodies to influenza A(H5N1) virus clade 2.3.4.4b in 96.8% (61/63) of serum samples from healthy adults in Hong Kong in 2020. In contrast, antibodies at low titers were detected in 42% (21/50) of serum samples collected in 2009. Influenza A(H1N1)pdm09 and A(H5N1) titers were correlated.
The A/goose/Guangdong/1/1996-like (GsGD-like) highly pathogenic avian influenza A(H5N1) viruses were first identified in 1996 and have continuously evolved into antigenically distinct hemagglutinin (HA) clades that have substantially affected animal and human health. Before 2005, the GsGd-like virus mainly circulated in Asia among domestic poultry. Spillover infections from domestic poultry to wild migratory birds have enabled intercontinental spread to Europe, the Middle East, Africa, and North America, as previously observed in 2005 (clade 2.2 virus) and in 2014–2015 (clade 2.3.4.4c virus) (1). Since 2016, the clade 2.3.4.4b viruses have undergone a 3rd wave of intercontinental spread and have become enzootic among wild birds as of 2021 (2,3). Currently, the GsGD-like H5N1 viruses have been reported in all continents except Oceania and Antarctica. Expanded genetic diversity and geographic distribution has led to spillover events into numerous mammal species and sporadic human infections (4).
Highly pathogenic avian influenza A(H5N1) virus has not yet achieved efficient transmissibility in humans, but the current epidemiology of H5N1 2.3.4.4b lineage raises concerns of possible pandemic potential. Population immunity to an emerging influenza virus is one of the key parameters considered in assessing its pandemic risk according to the Centers for Disease Control and Prevention influenza risk assessment tool (https://www.cdc.gov/flu/pandemic-resources/national-strategy/risk-assessment.htm) and the World Health Organization tool for influenza pandemic risk assessment (https://www.who.int/teams/global-influenza-programme/avian-influenza/tool-for-influenza-pandemic-risk-assessment-(tipra)External Link). Neutralizing antibodies targeting the HA receptor-binding domain and antibodies that inhibit neuraminidase (NA) activity have been shown to correlate with protection against influenza infection (5,6). We evaluated whether healthy adults possess cross-reactive hemagglutination inhibition (HAI) and neuraminidase inhibition (NAI) antibodies to H5N1 virus through previous exposure to seasonal influenza infections.
Abstract
We detected high titers of cross-reactive neuraminidase inhibition antibodies to influenza A(H5N1) virus clade 2.3.4.4b in 96.8% (61/63) of serum samples from healthy adults in Hong Kong in 2020. In contrast, antibodies at low titers were detected in 42% (21/50) of serum samples collected in 2009. Influenza A(H1N1)pdm09 and A(H5N1) titers were correlated.
The A/goose/Guangdong/1/1996-like (GsGD-like) highly pathogenic avian influenza A(H5N1) viruses were first identified in 1996 and have continuously evolved into antigenically distinct hemagglutinin (HA) clades that have substantially affected animal and human health. Before 2005, the GsGd-like virus mainly circulated in Asia among domestic poultry. Spillover infections from domestic poultry to wild migratory birds have enabled intercontinental spread to Europe, the Middle East, Africa, and North America, as previously observed in 2005 (clade 2.2 virus) and in 2014–2015 (clade 2.3.4.4c virus) (1). Since 2016, the clade 2.3.4.4b viruses have undergone a 3rd wave of intercontinental spread and have become enzootic among wild birds as of 2021 (2,3). Currently, the GsGD-like H5N1 viruses have been reported in all continents except Oceania and Antarctica. Expanded genetic diversity and geographic distribution has led to spillover events into numerous mammal species and sporadic human infections (4).
Highly pathogenic avian influenza A(H5N1) virus has not yet achieved efficient transmissibility in humans, but the current epidemiology of H5N1 2.3.4.4b lineage raises concerns of possible pandemic potential. Population immunity to an emerging influenza virus is one of the key parameters considered in assessing its pandemic risk according to the Centers for Disease Control and Prevention influenza risk assessment tool (https://www.cdc.gov/flu/pandemic-resources/national-strategy/risk-assessment.htm) and the World Health Organization tool for influenza pandemic risk assessment (https://www.who.int/teams/global-influenza-programme/avian-influenza/tool-for-influenza-pandemic-risk-assessment-(tipra)External Link). Neutralizing antibodies targeting the HA receptor-binding domain and antibodies that inhibit neuraminidase (NA) activity have been shown to correlate with protection against influenza infection (5,6). We evaluated whether healthy adults possess cross-reactive hemagglutination inhibition (HAI) and neuraminidase inhibition (NAI) antibodies to H5N1 virus through previous exposure to seasonal influenza infections.