Flu News Friday: The Latest in Influenza Vaccines

The Influenzer Initiative
5 min readAug 13, 2021


August 13, 2021

Negatively-stained transmission electron microscopic image of influenza A (H7N9) virus. Credit: CDC Public Health Image Library

1. Universal Influenza Virus Neuraminidase Vaccine Elicits Protective Immune Responses against Human Seasonal and Pre-pandemic Strains

Skarlupka et al., Journal of Virology / August 10, 2021

While the primary target antigen for many influenza vaccines is the hemagglutinin (HA) surface protein, the neuraminidase (NA) surface protein has a slower evolutionary rate, “crossing” more HA subtypes, making it a potential target in the design of broadly protective influenza vaccines. Using computationally optimized broadly reactive antigen (COBRA) methodology, an N1-NA universal influenza vaccine candidate was designed using human, avian, and swine origin influenza NA sequences from 1990 to 2015. After challenge with zoonotic and pre-pandemic strains (pH1N1, swH1N1, and H5N1) as well as current, seasonal, human-origin strains (H1N1), the vaccine elicited cross-reactive antibodies in a mouse model. Building upon their previous work on an HA-based COBRA influenza vaccines, the authors believe the N1-I COBRA NA antigen has the “potential to be a complementary component” in a multiantigen UIV containing both HA and NA antigens.

2. Influenza Vaccine Protects Against Severe COVID-19

Killian Meara, Contagion Live / August 8, 2021

After a retrospective study of over 74 thousand patients and their electronic medical records, scientists concluded that individuals in the group who received an influenza vaccine before SARS-CoV-2 infection experienced a protective effect against adverse outcomes, including sepsis, stroke, deep vein thrombosis (DVT), emergency department visits and intensive care unit (ICU) admissions. The study is the largest of its kind to examine the flu vaccine and COVID-19 infection, drawing upon patient data from high-income countries around the world.

Note: a flu vaccine should not serve as a replacement for a COVID-19 vaccine.

3. A non-neutralizing antibody broadly protects against influenza virus infection by engaging effector cells

Ko et al., PLOS Pathogens / August 5, 2021

Antibodies with protective efficacy generally have neutralizing activity. However, scientists identified a specific non-neutralizing monoclonal antibody (mAb 651) with an ability to provide remarkable protective efficacy against influenza infection in vivo. The antibody was isolated from mice immunized with a protein-based universal influenza vaccine. Despite its non-neutralizing activity, mAb 651 employs Fc receptor-mediated effector functions and has with a broad range of recognition against the hemagglutinin (HA) head. The antibody was found to reduce the inflammatory responses and mortality associated with influenza infection. The study results have implications for the development of influenza therapeutics and studies on vaccine efficacy.

4. Global public health security and justice for vaccines and therapeutics in the COVID-19 pandemic

Hotez et al., E Clinical Medicine / August 3, 2021

Members of the Lancet Commission for COVID-19 Task Force for vaccines and therapeutics review the COVID-19 pandemic through a health justice and access lens. The authors discuss a list of actionable recommendations within the areas of collaboration and knowledge sharing, health system strengthening, capacity building and training, vaccine confidence, global governance, and international diplomacy. These measures are “urgently needed to achieve effective global COVID-19 vaccine and therapeutic security, justice, and equity.”

5. A M2 protein-based universal influenza vaccine containing Advax-SM adjuvant provides newborn protection via maternal or neonatal immunization

Sakala et al., Vaccine / August 3, 2021

Current seasonal influenza vaccines are not approved for children under six months due to potential adverse reactions and lower vaccine efficacy. Because of the high burden of influenza in infants associated with their näive adaptive immune systems, maternal immunization is recommended. However, studies show that in infants, passively-transferred maternal antibodies are not long-lasting. Scientists evaluated the protective efficacy of a universal influenza vaccine candidate targeting the matrix protein 2 ectodomain (m2e) with the Advax-SM adjuvant in a mouse model. The CapM2e + Advax-SM vaccine demonstrated protection against H1N1 and H3N2 challenges through both passive maternal immunization and direct neonatal immunization, evidenced by high m2e antibody levels.

6. Seasonal influenza during the COVID-19 pandemic in Bangladesh

Akhtar et al., PLOS One / August 3, 2021

Scientists used hospital-based surveillance data to examine the effects of COVID-19 community mitigation measures on influenza activity in Bangladesh. The findings suggest that during COVID-19, seasonal influenza activity in Bangladesh was shorter, delayed, and less intense compared to previous influenza seasons. The study contributes to growing evidence of altered seasonal influenza activity around the world occurring during the COVID-19 pandemic.

7. The Human Antibody Response to the Influenza Virus Neuraminidase Following Infection or Vaccination

Rajendran et al., Vaccines / August 2, 2021

Conventional seasonal flu vaccines target hemagglutinin (HA), a surface protein that is immunodominant and evolutionarily hypervariable, with high immune selective pressure. This immunodominance means antibody responses are more often directed toward a particular epitope (HA) over other epitopes, such as the neuraminidase (NA) surface protein. However, because NA has a slower rate of antigenic evolution and is under less selective pressure, NA is an attractive target for developing influenza vaccines. Scientists review the human antibody responses toward NA and discuss the potential of targeting NA for influenza vaccines with improved efficacy and greater breadth of protection.

8. Airborne Transmission of Avian Origin H9N2 Influenza A Viruses

Cáceres et al., Preprints.org / July 30, 2021

Avian-origin influenza A viruses, most frequently H5, H7 and H9 subtypes, can cause human infection when zoonotic (interspecies) transmission occurs. Human cases of zoonotic influenza have been associated with H9 circulating endemically in poultry populations. H9N2 is of pandemic concern since avian-mammalian viral reassortments have caused the emergence of pandemic viral strains. Scientists review the molecular mechanisms that may drive zoonotic events with H9N2, focusing on factors allowing viral replication and transmission.

9. Funding Opportunities & Information

Broad-Spectrum RNA Therapeutic for COVID-19 and Influenza [Licensing Opportunity]

Wyss Institute / Opened March 2021

Newcastle Disease Virus-Like Particle Displaying Prefusion Stabilized SARS-CoV-2 Spike and Its Use [Licensing Opportunity]

National Institute of Allergy & Infectious Diseases / Opened April 23, 2021

Emily Graul, Sabin Vaccine Institute

Visit Influenzer.org to learn more about Sabin’s journey to accelerate the development of a universal influenza vaccine. @TheInfluenzers



The Influenzer Initiative

Engaging and informing expertise from across research disciplines and industry sectors to drive innovation towards universal influenza vaccine development.