Life science companies developing bird flu vaccines are gaining attention as the avian influenza subtype H5N1 becomes an increasing concern.
The United States is in the midst of an H5N1 bird flu outbreak that began in February 2024 and is now threatening the nation’s poultry and cattle industries. With poultry farmers across the US needing to cull their flocks if the virus is detected to prevent it spread, egg prices are shocking shoppers at the country’s grocery stores. Highly pathogenic avian influenza (HPAI) has also spread to cattle and other mammals, including cats.
Human avian influenza cases have so far been rare during this outbreak in the US, as currently the virus is only spread to humans through exposure to infected animals. As of February 27, 2025, 67 human cases have been detected in the country, and one death has been reported. However, concerns such as the possibility of mutations that could increase the chance of human-to-human transmission are stoking calls for better preparedness and access to bird flu vaccines.
In this article:
Is there a vaccine for bird flu?
There are several bird flu vaccines approved for treating avian influenza in humans, with others under development.
The Center for Disease Control and Prevention (CDC), a US federal agency under the Department of Health and Human Services, currently holds three different US Food and Drug Administration (FDA) approved vaccines in its strategic national stockpile that can be rapidly updated to address the current strain.
In the United States, the vaccines would be reserved for workers in the poultry industry if human cases escalate and could be scaled up further if needed in the case of a bird flu pandemic in humans.
Health Canada has authorized two H5N1 vaccines and laid out a framework for deciding whether to use the vaccines in a non-pandemic context, including increased human cases, human-to-human transmission and increasing severity of outcomes.
Which companies are producing vaccines for bird flu?
Some of the biggest companies in the pharmaceutical industry are either producing vaccines for bird flu or actively developing new drug candidates to fight the virus. There are also a number of large-cap and small-cap life science companies with avian influenza vaccines under development.
Below are eight bird flu vaccine stocks for investor consideration and details of their work on avian influenza. The stocks are listed by market cap based on figures retrieved from TradingView’s stock screener on March 12, 2025.
1. Sanofi (NASDAQ:SNY)
Market cap: US$148.84 billion
Sanofi develops therapeutic products for diabetes and cardiovascular diseases, oncology, immunology, multiple sclerosis, rare diseases, and rare blood disorders. The French multinational pharmaceutical company is also one of the world’s largest manufacturers of vaccines.
Sanofi’s H5N1 vaccine became the first to be approved by the US FDA back in 2007. Today, it is one of only three US FDA-approved H5N1 vaccines held in the US national stockpile, joined by vaccines from two other pharma firms on this list, CSL Seqirus and GSK.
In October 2024, the three pharma companies were awarded a combined US$72 million by the US Administration for Strategic Preparedness and Response. The companies will prepare doses of their vaccines to be available if needed, and ‘manufacture additional bulk influenza antigen … from seed stocks that are well matched to circulating strains.’
2. Pfizer (NYSE:PFE)
Market cap: US$147.29 billion
Pfizer is a world-renowned research pharmaceutical company developing drugs in a wide range of areas, including oncology, inflammation and immunology, vaccines, internal medicine and rare diseases. Pfizer and BioNTech created the first FDA-approved mRNA-based COVID-19 vaccine in 2020.
Pfizer’s mRNA technology could be targeted at producing an avian flu vaccine. In a May 2024 press release, the company stated that it is prepared to address an H5 group influenza pandemic, and reported that in late 2023 it had ‘initiated a randomized Phase 1 study to evaluate the safety, tolerability, and immunogenicity of multiple doses of nucleoside-modified mRNA (modRNA) based pandemic influenza vaccine candidate.’
3. GSK (NYSE:GSK)
Market cap: US$81.76 billion
British multinational biotech company GSK has three main business divisions: pharmaceuticals, consumer healthcare and vaccines. Its vaccine Arexvy is the world’s first respiratory syncytial virus (RSV) vaccine for older adults and is approved for ages 50 and up.
GSK subsidiary ID Biomedical Corporation of Quebec produces Arepanrix, an H5N1 virus monovalent vaccine, is among the three avian flu vaccines in the US stockpile.
“GSK’s H5N1 pandemic vaccine can generate some cross-neutralizing antibodies against the current circulating strains and is recognized as an important tool in reducing illness during a possible H5N1 pandemic,” a GSK spokesperson told PharmaVoice. “The vaccine is designed to be updated with the latest circulating strain of interest, as identified by the WHO.”
In February 2025, the Public Health Agency of Canada announced that through an existing deal with GSK, it has secured an initial supply of 500,000 doses of its avian influenza vaccine.
GSK also has a mRNA-based H5N1 pre-pandemic vaccine in Phase 2 studies for adults 18 and older. GSK’s mRNA candidate vaccines were previously being developed in partnership with German biopharma CureVac, another company on this list. However, the two restructured the partnership in July 2024, and GSK now has full rights to development, manufacturing and commercialization.
4. CSL (ASX:CSL,OTCQX:CMXHF)
Market cap: US$75.51 billion
Australian multinational biotechnology firm CSL is the parent company of CSL Seqirus, one of the world’s largest influenza vaccine makers. CSL Seqirus has production facilities in the United States, the United Kingdom and Australia.
CSL Seqirus’ Audenz is among the three avian flu vaccines that make up US stockpiles. The company describes Audenz, which the FDA approved in 2020, as ‘the first-ever adjuvanted, cell-based influenza vaccine designed to protect against influenza A (H5N1) in the event of a pandemic.’
CSL Seqirus has a manufacturing facility in North Carolina that was built through a public-private partnership with the US government in 2009. According to the company, the facility is the world’s largest cell-based influenza vaccine producer and its highly scalable production method means it’s capable of delivering 150 million influenza vaccine doses within a six-month timeframe as part of an influenza pandemic response.
5. Moderna (NASDAQ:MRNA)
Market cap: US$13.03 billion
Moderna leads the world in the field of mRNA-based medicine from immuno-oncology to infectious diseases, as best demonstrated by its rapid deployment of effective COVID-19 vaccines. The company’s integrated manufacturing plant allows for both clinical and commercial production.
Moderna’s mRNA-based bird flu vaccine mRNA-1018 is undergoing a Phase 1/2 study targeting H5 and H7 avian influenza viruses.
In January 2025, the US Department of Health and Human Services (HHS) under the Biden Administration stated it would award Moderna US$590 million to “accelerate the development of mRNA-based pandemic influenza vaccines and enhance mRNA platform capabilities so that the U.S. is better prepared to respond to other emerging infectious diseases.” This includes its investigational avian flu vaccine.
Bloomberg reported in late February that funding is now in question as Robert F. Kennedy Jr., a long-time anti-vaccine activist, has taken the reins of the HHS under the Trump administration. Republican lawmakers in several states are also putting forth legislation to ban mRNA vaccines.
6. Novavax (NASDAQ:NVAX)
Market cap: US$1.27 billion
American vaccine developer Novavax has a pipeline of early and late-stage vaccine candidates targeting respiratory viruses and other serious infectious diseases. The biotech’s platform is based on its proprietary recombinant protein-based nanoparticle and Matrix-M adjuvant technology.
Sanofi signed a US$1.2 billion co-exclusive license in May 2024 to co-commercialize Novavax’s adjuvanted COVID-19 vaccine through much of the world.
Novavax is also conducting pre-clinical studies on a vaccine for H5N1 avian pandemic influenza using its novel approach to immunization. According to the company, ‘Non-human primate studies have shown (its) vaccine candidate can produce protective levels of immunity after a single dose.’
7. CureVac (NASDAQ:CVAC)
Market cap: US$708.81 million
CureVac is a pioneer in developing mRNA medicines, and the first biotech company in the world “to successfully harness mRNA for medical purposes,” according to its company website. The company’s mRNA-based pipeline is based its on its proprietary RNA technology platform. It focuses on three therapeutic areas: prophylactic vaccines, cancer immunotherapies and molecular therapies.
CureVac also has an in-house GMP manufacturing facility capable of large-scale production of vaccine doses.
In 2024, CureVac, in partnership with GSK, began a Phase 1/2 study in the United States on an investigational mRNA-based bird flu vaccine for healthy younger adults aged 18 to 64 and healthy older adults aged 65 to 85 years of age. The vaccine candidate has since been fully licensed to GSK.
8. Arcturus Therapeutics (NASDAQ:ARCT)
Market cap: US$358.25 million
California-based Arcturus Therapeutics is a global commercial mRNA medicines and vaccines company. Its pipeline is focused on the development of infectious respiratory disease vaccines.
Arcturus is developing an avian flu vaccine based on its STARR self-amplifying mRNA vaccine platform technology. In 2022, the company was awarded US$63.2 million by the US HHS to support development of this vaccine for rapid pandemic influenza response. Phase 1 clinical trials for its H5N1 vaccine candidate began in January and is fully funded by the Biomedical Advanced Research and Development Authority, part of the US HHS.
Antiviral influenza stocks
Life science stocks with commercial or clinical-stage antiviral influenza medications are also worth considering for investors interested in bird flu stocks. Here are a few to get you started, listed in alphabetical order.
CoCrystal Pharma (NASDAQ:COCP)CoCrystal Pharma is a clinical-stage biotech company with a focus on developing antiviral treatments, specifically for influenza, norovirus and COVID-19. The company’s oral influenza PB2 inhibitor CC-42344 is targeted at pandemic and seasonal influenza. Currently in Phase 2a studies, the treatment has shown in vitro activity against the avian influenza A PB2 protein.
NanoViricides (NYSEAMERICAN:NNVC)NanoViricides is a clinical stage nanomedicine technology company. Its lead drug candidate is NV-387, a broad spectrum antiviral therapy that works by mimicking a host-side signature that viruses respond to, meaning it should be effective even as viruses mutate over time. NV-837 is developed to treat respiratory viral infections such as RSV, COVID, Long COVID, and H5N1 as well as Mpox, smallpox and measles infections. The company has successfully completed Phase 1 studies.
Roche (OTCQX:RHHBY,SWX:RO)Switzerland-headquartered F. Hoffmann-La Roche, commonly known as Roche, is one of the world’s largest pharmaceutical companies by revenue. Along with hematology, oncology, neuroscience, and women’s health, the company also targets infectious diseases. Its drug Tamiflu is one of the leading seasonal influenza antiviral treatments, and it can be used to treat avian flu as well.
Traws Pharma (NASDAQ:TRAW)Traws Pharma is a clinical stage company leveraging its expertise in small molecule chemistry, artificial intelligence and machine learning in the efficient development of medicines addressing respiratory viral diseases. The company’s single-dose H5N1 bird flu antiviral, tivoxavir marboxil, is entering Phase 2 studies in the first half of 2025.
FAQs for bird flu vaccines
Is there a bird flu vaccine for chickens?
There are bird flu vaccines for chickens, and farmers in nations such as China, France, Egypt and Mexico use them to inoculate their flocks.
However, the avian flu vaccines for birds are not commonly used in the United States as they pose logistical challenges and create barriers to trade. In terms of trade, some US trading partners won’t purchase vaccinated chickens as the vaccine can mask an avian flu infection.
Instead, biosecurity measures such as sanitation and protective wear for workers, and culling of infected flocks are more common practices in the United States.
In response to the current bird flu outbreak, in mid-February 2025, the US Department of Agriculture conditionally approved a bird flu vaccine for chickens made by Zoetis (NYSE:ZTS), the world’s largest producer of medicine and vaccinations for pets and livestock.
Is there a bird flu vaccine for cattle?
There are bird flu vaccines for cattle under development. For example, Medgene, a privately held animal health company based in South Dakota, is developing an H5N1 vaccine for cattle that as of late February 2025 is waiting on imminent conditional approval from the US Department of Agriculture. The company has signed a distribution agreement with global animal health company Elanco Animal Health (NYSE:ELAN) for the vaccine.
Is there a bird flu vaccine for cats and dogs?
While both animals can catch avian flu, there are no commercial bird flu vaccines are currently available for cats and dogs. Cats are at higher risk of contracting HPAI bird flu than dogs, but owners of both should take precautionary measures.
The American Veterinary Medical Association advises cats should be kept indoors. Pet owners should keep outdoor pets, including backyard chicken flocks, away from the wild birds, poultry and cattle.
Additionally, pet owners must avoid feeding pets raw meat or poultry and unpasteurized milk, and prevent pets from eating dead birds or other animals.
Securities Disclosure: I, Melissa Pistilli, hold no direct investment interest in any company mentioned in this article.
