H5N1 Avian Flu Outbreak: Current Ballgame

Globally, since 2020, avian flu has gained heightened attention as a probable epidemic that can be caused and, subsequently, a significant research-based momentum. H5N1 bird flu remains one of the major concerns due to its potential for cross-species transmission and severe impact on both avian and mammalian populations. Vigilance and research are crucial for understanding and managing this virus effectively.

H5N1 Avian Flu Virus Biology

Like other influenza viruses, the H5N1 virus is an enveloped virus with an eight-segment single-stranded RNA in the core and two surface proteins on the envelope: hemagglutinin and neuraminidase. These proteins are responsible for glycosylation, which is necessary for cell entry and exit.

Fig 1: H5N1 Avian Flu Virus

H5N1 belongs to the goose/Guangdong 2.3.4.4b hemagglutinin phylogenetic clade. The human isolate indicates clade 2.3.4.4b of avian influenza A H5N1, wherein the amino acid motif Gln-Ser-Gly at residues 226–228 of the hemagglutinin protein represents an avian-like receptor binding preference. Currently, the A (H5N1) viruses have not acquired the ability to sustain transmission among humans. The available epidemiological and virological evidence suggests that there is no substantial evidence of adaptive mutations in the virus that would facilitate human-to-human transmission. Hence, the likelihood of human-to-human spread is low. However, if the clade 2.3.4.4b of A H5N1 virus continued to spread worldwide and ongoing dynamic evolution with mutations and re-assortment, the risk of HPAI virus infection in humans might Increase.

Demographic & Epidemiologic Analysis of the Infections Worldwide

The latest CDC report shows that H5N1 bird flu is concurrently widespread among wild birds. However, the public health risk is comparatively low. Since 2022, only 5 human infection cases have been reported in the US, all of which resulted from infected animals’ exposure. The below-presented graphs show the epidemiologic analysis of the infected states –

Table 1. No. of Species Infected in 2024 (as per CDC)

Fig 2: Epidemiological Distribution

How Long Would It Take to Roll Out a Bird Flu Vaccine for Humans?

The avian influenza vaccines currently available in the market do not really make use of the same messenger ribonucleic acid (mRNA) technology that was used for COVID-19.

 Candidate vaccine viruses (CVVs) developed against related clade 2.3.4.4b viruses are available for vaccine manufacturing as and when necessary. The preliminary analysis indicates a strong possibility of providing reasonable protection against H5N1 influenza viruses. In addition to the above, seasonal flu vaccines do not provide protection against these viruses, which further makes it hard to develop specific vaccine candidates.

Public Health Response Actions

Due to its recent spread and the SARS-CoV2 pandemic that hugely impacted the lives and market globally, avian flu has gained much response worldwide, encircling a series of public health concerns, including the traceability of animal-to-human transmission. The parameters that are required to be well taken care of in light of the identification of any human transmission include

• Protective actions around wild birds
• Epidemiological investigations and disinfection of the patient’s suspected exposure areas
• Contact tracing, isolation, testing, and monitoring for close contacts
• Sample testing for chickens and ornamental birds near the patient’s residence
• Officially requesting the Health Department of specific area-in-check to keep vaccines and other supplies timely available for patient management and containment of potential outbreaks

Market Trends & Major Competitors

Market giants, including GSK, CSL Seqirus, and Sanofi, are actively working in the field of seasonal influenza production capacity in collaboration with the US government and have made promising advances in scaling up the production of avian flu vaccines, if necessary.

In April 2024, CureVac, in collaboration with GSK, announced the Start of the Combined Phase 1/2 Study in Avian Influenza (H5N1).

Gamma Vaccines’ lead product, GammaFlu®, offers broader spectrum immunity to influenza viruses like Avian Influenza.

In March 2024, a large population of poultry flocks was destroyed in France. It had deployed the German giant Boehringer Ingelheim and France’s Ceva Animal Health to supply bird flu vaccines as part of an unprecedented vaccination campaign against the disease in the area.

In July 2024, Moderna received a grand funding of $176 million from the Biomedical Advanced Research and Development Authority (BARDA), supporting late-stage testing of vaccines targeting the H5 influenza virus.

Fig 3: Major Vaccine Players

Conclusion

With the larger impact of COVID-19 on the population, the air has thickened around the possible epidemic outbreak of the Avian H5N1 flu, which is expected to cause a lesser but significant impact on the current population. Also, as per the studies, people affected by COVID-19 in the past have a probable lesser active shield towards this. However, animal-to-human or human-to-human transmission rates are comparatively slow, and all eyes are on mitigating the possibilities of another pandemic announcing itself soon into the global healthcare scare.