Skip to main content

Pre-existing cross-reactive #immunity to highly pathogenic avian #influenza 2.3.4.4b #H5N1 virus in the #USA

Image
By G.M.

 


Abstract

The unprecedented 2.3.4.4b. A(H5N1) outbreak in dairy cattle, poultry, and spillover to humans in the United States (US) poses a major public health threat. Population immunity is a critical component of influenza pandemic risk assessment. We assessed the pre-existing cross-reactive immunity to 2.3.4.4b A(H5N1) viruses and analyzed 1794 sera from 723 people (0.5–88 yrs) in multiple US geographic regions during 2021–2024. Pre-existing neutralizing and hemagglutinin (HA)-head-binding antibodies to A(H5N1) were low, but there were substantial cross-reactive binding antibodies to N1 neuraminidase (NA) of 2.3.4.4b A(H5N1). Antibodies to group 1 HA stalk were also prevalent and increased with age. A(H1N1)pdm09 infection and influenza vaccination did not induce neutralizing antibodies to A(H5N1) viruses but induced significant rise of functional NA inhibition (NAI) antibodies to N1 of 2.3.4.4b A(H5N1), and group 1 HA stalk antibodies. Moreover, pre-pandemic stockpiled 2.3.4.4c vaccine can elicit cross-reactive neutralizing antibodies to 2.3.4.4b A(H5N1) viruses. Understanding population susceptibility is essential for pandemic preparedness.

Source: 


Link: https://www.nature.com/articles/s41467-025-66431-2

____

Labels:

Comments

Post a Comment

Popular posts from this blog

#Neuroinvasive #Oropouche virus in a patient with #HIV from extra-Amazonian #Brazil

By G.M.
{Excerpt} A novel reassortant Oropouche virus (OROV) lineage (with medium [M], large [L], and small [S] RNA segments : M1L2S2) has driven Brazil's largest and most geographically widespread OROV epidemic , expanding beyond the endemic Amazon basin to establish local transmission across multiple Brazilian states and other previously unaffected Latin American countries . The rapid spread of this lineage underscores its evolutionary potential and reinforces its significance as a public health threat .1 Similar to chikungunya and Zika viruses, expanding arboviruses can exhibit unexpected clinical and epidemiological shifts , including vertical transmissions , neuroinvasive effects, and potentially fatal outcomes.2–4 Although OROV typically causes self-limited febrile illness, accumulating clinical and experimental evidence suggests neurotropic potential .5 This Correspondence describes the first confirmed case of neuroinvasive OROV infection caused by the emergent M1L2S2 lineage in ext...
Post a Comment
Read more »

No evidence of immune #exhaustion after repeated #SARS-CoV-2 #vaccination in vulnerable and healthy populations

By G.M.
Abstract Frequent SARS-CoV-2 vaccination in vulnerable populations has raised concerns that this may contribute to T cell exhaustion , which could negatively affect the quality of immune protection. Herein, we examined the impact of repeated SARS-CoV-2 vaccination on T cell phenotypic and functional exhaustion in frail older adults in long-term care (n = 23), individuals on immunosuppressive drugs (n = 10), and healthy adults (n = 43), in Canada . Spike-specific CD4+ and CD8+ T cell levels did not decline in any cohort following repeated SARS-CoV-2 vaccination, nor did the expression of exhaustion markers on spike-specific or total T cells increase. T cell production of multiple cytokines (i.e. polyfunctionality) in response to the spike protein of SARS-CoV-2 did not decline in any cohort following repeated vaccination. None of the cohorts displayed elevated levels of terminally differentiated T cells following multiple SARS-CoV-2 vaccinations. Thus, repeated SARS-CoV-2 vaccination was...
Post a Comment
Read more »

Chimeric #hemagglutinin and #M2 #mRNA #vaccine for broad #influenza subtype protection

By G.M.
Abstract Since multiple and unpredicted influenza viruses cause seasonal epidemics and even high-risk pandemics , developing a universal influenza vaccine is essential to provide broad protection against various influenza subtypes. Combined with the mRNA lipid nanoparticle-encapsulated (mRNA-LNP) vaccine platform and chimeric immunogen strategy , we developed a novel cocktail mRNA vaccine encoding chimeric HAs (cH5/1-BV, cH7/3) and intact M2 (termed Fluaxe), which confers broad protection against major circulating IAVs and IBVs , as well as highly pathogenic avian influenza . Two-dose intramuscular immunization of Fluaxe in mice elicited cross-reactive neutralizing antibodies , T cell responses, and long-lived immunity, resulting in robust protection against multiple lethal influenza virus infections and severe acute lung injuries . In particular, intramuscular administration stimulated systemic immunity together with a prominent lung tropism of memory cells . Moreover, Fluaxe immuniza...
Post a Comment
Read more »