- Manuscript highlights development of robust responses to both influenza and COVID-19 and protection against the SARS-CoV-2 virus
- Data shared via preprint server for biology, bioRxiv, ahead of publication
Novavax, Inc. announced data from a preclinical study of the company’s combination quadrivalent seasonal flu vaccine (NanoFlu™) and COVID-19 vaccine candidate (NVX-CoV2373). The NanoFlu/NVX-CoV2373 combination vaccine demonstrated positive immune responses to both influenza and SARS-CoV-2.
The manuscript, titled ‘Combination Respiratory Vaccine Containing Recombinant SARS-CoV-2 Spike and Quadrivalent Seasonal Influenza Hemagglutinin Nanoparticles with Matrix-M™ Adjuvant,’ studied a combination vaccine comprising a quadrivalent nanoparticle influenza vaccine formulated together with a recombinant SARS-CoV-2 spike protein vaccine and Matrix-M™ adjuvant. The combination vaccine elicited robust responses to both influenza A and B and protected against the SARS-CoV-2 virus. Clinical studies of the combination vaccine are expected to begin by the end of the year.
The preclinical study found that the combination NanoFlu/NVX-CoV2373 (qNIV/CoV2373) vaccine induced functional influenza and COVID antibodies in ferrets. Hemagglutination inhibition (HAI) and ACE2 receptor-inhibiting titers were comparable between immunization with the combination vaccine and with its respective component vaccines. Antibody titers were elevated two weeks after a single dose and increased even further two weeks following a second immunization.
Hamsters that received the combination NanoFlu/NVX-CoV2373 vaccine had elevated levels of SARS-CoV-2 anti-S IgG two weeks after the first immunization, which increased significantly after a second dose, with levels comparable to animals that received the NVX-CoV2373 vaccine alone. Human ACE2 receptor inhibiting antibody levels responded similarly. The immune responses to influenza A and B strains elicited by NanoFlu/NVX-CoV2373 were comparable to immunization with NanoFlu alone. Further, the combination vaccine induced antibodies against SARS-CoV-2 neutralizing epitopes, including at hidden or cryptic sites, that are common between USA-WA1 and the B.1.351 variant.
Protection after SARS-CoV-2 challenge
When hamsters were challenged with SARS-CoV-2, animals immunized with NanoFlu/NVX-CoV2373 retained their body weight comparably to non-infected animals and those immunized with NVX-CoV2373 alone. An examination of viral load in the upper and lower respiratory tract showed that little or no virus was detected four days after COVID-19 infection in animals immunized with NanoFlu/NVX-CoV2373 or with just NVX-CoV2373. Microscopic and macroscopic observations of the lungs showed no remarkable findings in animals immunized with either the combination vaccine or with NVX-CoV2373 alone.