Avian Influenza Vaccines

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Last reviewed
February 25, 2024
Content Overview
Avian influenza and Pandemic vaccines are U.S. FDA approved and available.

Avian Influenza Vaccines 2024

The U.S. National Influenza Vaccine Modernization Strategy and the American Pandemic Preparedness Plan outlined the United States' (U.S.) priorities in avian influenza vaccines. According to the U.S. Centers for Disease Control and Prevention (CDC), about 20 million H5N1 and 12 million H7N9 vaccines were available in the National Strategic Stockpile in June 2023. The U.S. CDC also confirmed on June 20, 2023, an H5 candidate vaccine virus (CVV) similar to the hemagglutinin (H.A.) protein of H5N1 clade A(H5) Candidate Vaccine Virus Development (pg. 37). Furthermore, the CDC confirmed as of 2024, annual flu shots are unlikely to protect people during avian influenza (bird flu) outbreaks.

U.S. FDA-Approved Avian Influenza Vaccines

The U.S. Food and Drug Administration (FDA) authorized the Audenz™ (Influenza A(H5N1) Monovalent Vaccine, Adjuvanted) cell-based vaccine on January 31, 2020. Previously, the FDA licensed the second vaccine (STN#: 125419) to prevent H5N1 influenza on November 22, 2013. The vaccine, Influenza A (H5N1) Virus Monovalent Vaccine, Adjuvanted, was the first adjuvanted influenza vaccine approved for use in adults at increased risk of exposure to the H5N1 influenza virus subtype contained in the vaccine. The vaccine was manufactured by I.D. Biomedical Corporation is a Canadian subsidiary of GlaxoSmithKline Biologicals.

European Recommended Avian Influenza Vaccines

The European Medicine Agency's human medicines committee recommended at its February 2024 meeting Celldemic (zoonotic influenza vaccine (H5N1)(surface antigen, inactivated, adjuvanted, prepared in cell cultures)). This vaccine is intended for immunization during outbreaks of influenza coming from animals, including when public health authorities anticipate a possible pandemic. Incellipan (pandemic influenza vaccine (H5N1) (surface antigen, inactivated, adjuvanted, prepared in cell cultures)) is a pandemic preparedness vaccine intended for use only if a flu pandemic has been officially declared.

In the event of a bird flu pandemic, once the virus strain causing the pandemic is identified, the vaccine manufacturer can include that strain in the authorized pandemic preparedness vaccine and apply for the vaccine to be authorized as a 'final' pandemic vaccine. Because the vaccine's quality, safety, and efficacy have already been assessed with other potential pandemic strains, the authorization of the final pandemic vaccine can be accelerated.

The European Commission (EC) signed a framework contract on July 28, 2022, for the joint procurement of GSK's Adjupanrix, a pandemic influenza vaccine. As a result, EC Member States can purchase up to 85 million vaccine doses, if necessary, during an influenza pandemic.

CSL Seqirus BARDA Influenza Pandemic Vaccine Agreements

CSL Seqirus has been working with the U.S. Biomedical Advanced Research and Development Authority (BARDA), including numerous R&D and manufacturing activities and awards supporting BARDA's pandemic preparedness objectives. CSL Seqirus announced on August 28, 2023, that BARDA selected the company to deliver one bulk lot of H5N8 A/Astrakhan antigen to support the U.S. government's pandemic response readiness under contract number 75A50122D00004 ($46.3 million). This is the third award CSL Seqirus has received from BARDA related to the ongoing outbreak of HPAI, following the February 2022 award to produce an H5N8 A/Astrakhan virus vaccine seed and the subsequent October 2022 announcement of the selection of CSL Seqirus to deliver an H5N8 A/Astrakhan virus vaccine candidate for assessment in a Phase 2 clinical study. Under the $30.1 million agreement, BARDA is partnering with GSK and CSL Seqirus to manufacture investigational lots of H5N8 vaccines and clinically assess the safety, immunogenicity, and dose-sparing ability of adjuvants in combination with the manufactured vaccine candidates.

CSL Seqirus established and will maintain the required pandemic readiness to deliver 150 million doses of cell-based pandemic influenza vaccine within six months of an influenza pandemic declaration in the U.S. In 2022, the Holly Springs facility successfully achieved all of BARDA's criteria required to establish domestic manufacturing capability for innovative cell-based seasonal and pandemic influenza vaccines. On October 5, 2022, CSL announced results from the preclinical studies of the company's self-amplifying messenger RNA (sa-mRNA) influenza vaccine candidates. The data, published in Molecular Therapy – Methods and Clinical Development, indicate that the sa-mRNA influenza vaccine candidates produced a potent, cross-reactive immune response against pandemic and seasonal influenza strains, A(H5N1) and A(H1N1) (Swine flu).

The U.S. government awarded California-based Vir Bio a multi-year contract on October 4, 2022, with the potential for up to $1 billion to advance the development of a complete portfolio of innovative solutions (vaccines) to address influenza and other infectious disease threats. On September 15, 2009, four influenza vaccine manufacturers received approval from the FDA to use the influenza A (H1N1) 2009 monovalent influenza vaccine to prevent bird flu outbreaks caused by the 2009 pandemic influenza A (H1N1) virus.

The U.S. government purchased about 10,000 additional doses of RAPIVAB® in 2022. In 2014, RAPIVAB was approved for intravenous uncomplicated acute influenza in patients six months and older who have been symptomatic for no more than two days.

Japan Bird Flu Vaccines

Japan Health Ministry announced in May 2023 that it is changing its avian influenza vaccine stockpile from H7N9 to the H5N1 virus. On May 25, 2023, local media reported that Japan intends to stockpile 10 million vaccines for people. In 2018, Japan began culling infected chickens. In 2008, Japan started testing bird flu vaccine versions. And in 2003, after 79 years, a HAPI virus was detected in the dead chickens.

United Kingdom Influenza Pandemic Vaccines

The U.K. Health Security Agency announced on September 26, 2023, an advance purchase agreement with CSL Seqirus to produce over 100 million influenza pandemic vaccines if or when they are needed.

Avian Influenza Monoclonal Antibody

Vir Biotechnology, Inc. VIR-2482 is an intramuscularly administered investigational prophylactic monoclonal antibody that has demonstrated in vitro the ability to neutralize significant strains of influenza A that have arisen since the 1918 Spanish flu pandemic.

Avian Influenza Vaccines for Birds

The United States Department of Agriculture's Agricultural Research Service (APHIS) researchers confirmed on April 14, 2023, that they are currently testing several vaccine candidates for use with birds. The World Organisation for Animal Health (WOAH) announced on June 7, 2023, it issued a comprehensive report - Animal Health Forum on Avian Influenza – Policy to Action: The Case of Avian Influenza – Reflections for Change. It was recognized that a successful vaccination strategy must rely on authorized (bird flu) vaccines. "Vaccinating is not the end, it is just the beginning. Vaccination application needs to be managed along the supply chain, including a surveillance program to detect active infection in vaccinated animals," said Dr. David Swayne, Disease Expert and Forum rapporteur.

On May 16, 2023, APHIS approved the emergency use of an HPAI vaccine to prevent additional deaths of California Condors. The authorized vaccine is a killed, inactivated product conditionally licensed by APHIS' Center for Veterinary Biologics in 2016. Since the vaccine has not previously been tested against this strain of the HAPI virus in these species, the first step is a pilot safety study in North American vultures, a similar species. This vaccine trial will be conducted with surrogate vultures in North Carolina. As of June 2, 2023, all vultures that received the HPAI vaccine as part of the initial trial on May 16 appear to be in good health with no vaccine site reactions. The Service determined on October 16, 2023, that based on the results from Group 1, release birds for this fall and winter 2023 will be vaccinated with the Group 1 regimen (two 0.5ml doses) before release. The vaccine should provide some level of protection from mortality if the birds are exposed to the virus and likely decrease the degree to which an individual becomes ill. This will result in 14 additional birds being vaccinated, leading to 26 vaccinated release birds (including those in the trial). The release of individuals will continue to be dependent on the individual's behavior and conditions at the local release site.   

The DIVA strategy uses an inactivated oil emulsion vaccine containing the same haemagglutinin (H) subtype as the challenge virus but a different neuraminidase (N). The possibility of using the heterologous N subtype to differentiate between vaccinated and naturally infected birds was investigated by developing an "ad hoc" serological test to detect specific anti-N1 antibodies.