Diverse Range of Vaccines Crucial For Bird Flu Pandemic Preparedness

Author: Taylor & Francis Group
Published: 2024/05/29 - Updated: 2025/03/10
Publication Type: Informative
Peer-Reviewed: Yes
Topic: Avian Influenza (Bird Flu) - Publications List

Page Content: Synopsis - Introduction - Main - Insights, Updates

Synopsis: Range of vaccines platforms crucial for enhancing human pandemic preparedness following discovery of avian influenza spreading from cows to humans.

Why it matters: This peer-reviewed article emphasizes the critical need for a diverse array of vaccine platforms to bolster human preparedness against avian influenza viruses, particularly in light of recent cases where the H5N1 strain transmitted from cattle to humans. The research underscores that while inactivated vaccines are safe and cost-effective, offering antibody-based immunity, live attenuated vaccines (LAIVs) may provide broader protection by also engaging mucosal and cellular defenses. The study also highlights the potential of newer approaches, such as virus-like particle (VLP) and mRNA vaccines, which have shown promise in preliminary animal studies. For seniors and individuals with disabilities, who may face heightened risks during influenza outbreaks, this information is particularly pertinent, as it underscores the importance of advancing and diversifying vaccine strategies to ensure comprehensive protection for all segments of the population - Disabled World (DW).

Introduction

Vaccination remains the most effective strategy for avian influenza prevention and control in humans, despite varying vaccine efficacy across strains. That's according to the authors of a new review which delves into existing research into bird flu vaccines for humans.

Main Item

Published in the peer-reviewed journal Human Vaccines & Immunotherapeutics, the results of the paper are particularly timely following news last week (Wednesday 22nd May, 2024) that the bird flu strain H5N1 had once again, for a second time, jumped from cattle in America to a human - prompting fears of subsequent human-to-human infection, with possible critical consequences.

Instances of the avian influenza were first recognized in US cattle in March. Since then, this strain has mainly spread from cow-to-cow and scientists have discovered very high levels of virus in raw milk (pasteurized milk is safe, having shown viral RNA but not infectious virus). To-date two people, however, are known to have contracted the bird flu virus. Both patients - US farmers - only reported eye symptoms and with treatment they made a full recovery.

Following tests on the first human instance, it was seen that the strain had mutated to be better adapted to mammalian cells, but as long as that human didn't pass it onto another person it likely stopped the spread at that point. With the second case, the CDC has released a statement to say it has been monitoring influenza surveillance systems intently, especially in impacted states.

"There has been no sign of unusual influenza activity in people, including in syndromic surveillance," they report.

The concern now, though, is that if H5N1 continues to be given the environment in which to mutate (such as in close quarter cattle farms) - and this continues long enough - it has the potential to find a combination that will easily spread to humans.

The results of this new research, carried out by a team at the University of Georgia, USA, suggests vaccines still remain our "primary defense" against potential spread of avian influenzas such as the H5N1 and others assessed.

"The H5N1, H7N9, and H9N2 subtypes of avian influenza virus pose a dual threat, not only causing significant economic losses to the global poultry industry but also presenting a pressing public health concern due to documented spillover events and human cases," explains lead author Flavio Cargnin Faccin, who alongside his mentor Dr. Daniel Perez of the University of Georgia, USA, analyzed the current landscape of research into human vaccines for these bird flus.

"This deep delve into the landscape of avian influenza vaccines for humans shows vaccination remains the primary defense against the spread of these viruses."

The team examined studies of vaccines tested in mice, ferrets, non-human primates, and clinical trials of bird flu vaccines in humans, and assessed both established platforms and promising new directions.

The review carried out suggests inactivated vaccines are a safe and affordable option that primarily activate humoral immunity - the part of our immune system that produces antibodies.

Live attenuated influenza vaccines (LAIVs) are known to induce a wider immune response than inactivated vaccines, activating not only antibody production but also mucosal and cellular defenses. In this review, the authors suggest this broader response may offer greater protection, though, the authors suggest further research is needed to fully understand and harness its potential benefits for both human and agricultural applications.

The review also examined alternatives, such as virus-like particle (VLP) vaccines and messenger RNA (mRNA) vaccines, that have emerged more recently. Although VLP vaccines for bird flu have limited clinical trial data in humans, results from studies in mice and ferrets showed promise, the authors found. mRNA vaccines against H5N1 and H7N9 bird flu subtypes also generated a rapid and strong immune response in mice and ferrets, and, while data in humans is scarce, results from a phase 1 study of an H7N9 mRNA vaccine in healthy humans were "encouraging".

Overall, the team suggests "exploring and employing a diverse range of vaccine platforms", will be "crucial for enhancing pandemic preparedness and mitigating the threat of avian influenza viruses".

Related Information

Wild Birds in New York City Test Positive for Avian Flu: This is the first large-scale U.S. study of avian influenza in an urban area, and the first with active community involvement.
Dolphin in Florida Detected with Highly Pathogenic Avian Flu: Analyses ruled out the presence of other potential agents at play in the dolphin, verifying the presence of HPAI virus in both the lung and brain.
H5N1 Avian Flu Viruses Transmissible Between Humans Could Evolve in Nature: Avian flu viruses which are transmissible between humans could evolve in nature, and research provides insight into feasibility of virus becoming airborne transmissible.

Insights, Analysis, and Developments

Editorial Note: The emergence of avian influenza strains capable of crossing species barriers serves as a stark reminder of our vulnerability to pandemics. While the threat of avian influenza may seem distant to many, the recent global pandemic has underscored the importance of preparedness for zoonotic diseases. This article serves as a timely reminder that proactive measures and awareness are key to mitigating potential health risks. As we navigate an increasingly interconnected world, understanding and implementing these preventive strategies not only protects individuals but also contributes to the broader public health effort in containing the spread of infectious diseases. It is crucial that we remain vigilant and adaptable in the face of evolving health challenges, ensuring that all members of society, regardless of their abilities or age, have access to the information and resources needed to stay safe - Disabled World (DW).

Attribution/Source(s): This peer reviewed publication was selected for publishing by the editors of Disabled World (DW) due to its relevance to the disability community. Originally authored by Taylor & Francis Group and published on 2024/05/29, this content may have been edited for style, clarity, or brevity. For further details or clarifications, Taylor & Francis Group can be contacted at taylorandfrancis.com NOTE: Disabled World does not provide any warranties or endorsements related to this article.