Preclinical Intranasal COVID-19 Vaccine Candidate Data Demonstrate Durable Immune Response and Broad Protection

Research published in Journal of Virology

Athens, Ga. and San Jose, Calif., March 27, 2025 – Blue Lake Biotechnology, Inc., a clinical-stage intranasal vaccine company developing parainfluenza virus 5 (PIV5)-vectored vaccines that harness the full breadth of the immune system to protect against serious infectious diseases, and its affiliate CyanVac LLC today announced the recent publication of two preclinical studies in the Journal of Virology highlighting the durability of immune responses and broad protective efficacy of CVXGA, an intranasal COVID-19 vaccine candidate. 

“These studies provide compelling evidence that intranasal vaccination with CVXGA not only induces long-lasting immune responses but also serves as a highly effective booster against emerging variants,” said Biao He, Ph.D., founder and CEO of Blue Lake and CyanVac and corresponding author on the articles. “With the continued threat of SARS-CoV-2, and as new variants emerge, there is an urgent need for vaccines that offer broader, more durable protection. CVXGA’s potential to provide long-term COVID-19 protection through an ability to boost pre-existing immunity and generate mucosal, humoral, and cellular immune responses makes it a promising candidate for further clinical development.” 

In one of the studies, “A parainfluenza virus 5 (PIV5)-vectored intranasal SARS-CoV-2 vaccine (CVXGA1) elicits protective and long-lasting immunity in nonhuman primates,” CVXGA1 (a version of CVXGA that expresses the S-protein of the ancestral WA1 (Wuhan) strain of SARS-CoV-2) induced nasal IgA and a durable immune response in African green monkeys, with sustained IgG and IgA antibody levels detected beyond 245 days and peripheral blood mononuclear cell (PBMC) responses persisting for at least 180 days post-vaccination. These findings build the body of evidence supporting CVXGA’s durability and underscore the potential of CyanVac’s intranasal PIV5-based vaccine platform to address the challenge of waning immunity seen with currently approved COVID-19 vaccines.  

In the accompanying study, “Efficacy of parainfluenza virus 5 (PIV5)-vectored intranasal COVID-19 vaccine as a single dose primer and booster against SARS-CoV-2 variants,” an in vivo hamster model was used to evaluate the immunogenicity and efficacy of CVXGA1 as a booster following two doses of an mRNA vaccine. CVXGA1 provided strong protection against infection by the WA1 strain and multiple SARS-CoV-2 variants. Notably, the data suggest that CVXGA1 can serve as an effective booster vaccine, as it not only significantly enhanced pre-existing immunity in previously mRNA-vaccinated individuals, but it also outperformed an additional mRNA vaccine booster. The results indicate that the vaccine’s broad-based immune response offers superior protection beyond serum antibodies alone, reinforcing the potential of intranasal vaccination to address viral evolution and emerging variants. 

About CVXGA

CVXGA is a clinical-stage COVID-19 vaccine candidate based on a proprietary parainfluenza virus 5 (PIV5) vector that encodes the spike (S) protein of SARS-CoV-2. The PIV5 vector was developed at the University of Georgia and is based on a respiratory virus that is not known to cause disease in humans which has been commonly administered to dogs as part of combination distemper/kennel cough vaccines for decades. CyanVac and its affiliate, Blue Lake Biotechnology, are developing CVXGA as a single-dose, intranasal vaccine to prevent SARS-CoV-2 infection and serious complications associated with COVID-19. Preclinical studies have demonstrated that CVXGA is immunogenic and protective and prevents transmission of SARS-CoV-2. Phase 1 and Phase 2a clinical studies have shown that subjects dosed with CVXGA showed robust mucosal, cellular and humoral immune responses with limited or no reactogenicity and no serious adverse events assessed as related to the vaccine. 

About CyanVac and Blue Lake Biotechnology 

Blue Lake Biotechnology, Inc. and its affiliate, CyanVac LLC, are developing intranasal vaccines that harness the full breadth of the immune system to keep people healthy, prevent serious infectious diseases, and protect the health of vulnerable populations. Our platform mimics natural infections by expressing a protein from a targeted pathogen in a proprietary parainfluenza virus 5 vector. Clinical data have shown that administration of our intranasal vaccine candidates stimulates all three pillars of the immune system, including mucosal immunity, which may be beneficial in preventing transmission of pathogens and spread of disease. We have a robust clinical-stage pipeline of best-in-class vaccines designed to overcome the limitations of existing vaccine technologies. Our lead product candidates have demonstrated potential for efficacy against symptomatic infection following a single intranasal dose, with few vaccine-related side effects.

Learn more at Blue Lake Biotechnology.

CONTACTS: 

Carolyn Hawley 
Inizio Evoke Comms 
carolyn.hawley@inizioevoke.com   
619-849-5382 

Samuel Wu, Chief Business Officer  
Blue Lake Biotechnology, Inc. and CyanVac LLC   
swu@bluelakebiotechnology.com   
650-609-2231