DIFF Biotech's Novel Nasal Spray Influenza Vaccine Receives Clinical Trial Approval in China

Zhejiang Difference Biological Technology Co., Ltd. (DIFF Biotech (search)Search term) has achieved a significant regulatory milestone with its proprietary nasal spray influenza vaccine, DIFF-flu (search)Search drug, receiving clinical trial approval as a Class 1.2 innovative vaccine from China's National Medical Products Administration (NMPA). This marks the first domestically self-developed nasal spray influenza vaccine in China to advance into clinical trials.

Revolutionary M2 Gene-Modified Attenuation Technology

DIFF-flu (search)Search drug employs an innovative M2 gene-modification strategy that produces a replication-restricted vaccine strain, protected by multiple international invention patents. This approach achieves what the company describes as an optimal balance between robust attenuation and strong immunogenicity, generating a potent immune response while maintaining an exceptional safety profile.

"DIFF-flu (search)Search drug's clinical approval marks a major milestone for DIFF Biotech (search)Search term and a meaningful achievement for independent innovation in respiratory infectious disease prevention," said Dr. Jiasheng Song, Chief Executive Officer of DIFF Biotech. "As a next-generation attenuation platform, DIFF-flu is designed to achieve an optimal balance between immunogenicity and safety—an advance that holds significant potential for improving influenza protection."

The technology essentially places a "safety harness" on the virus to prevent uncontrolled replication, differentiating it from existing nasal spray vaccines that rely on cold-adapted attenuation. Current market vaccines allow the vaccine virus to replicate efficiently only at lower temperatures in the nasal cavity while limiting replication in the warmer lower respiratory system and lungs. However, because these strains can still replicate in nasal mucosa and cause mild viral shedding, they are generally not recommended for older adults or immunocompromised individuals.

Enhanced Safety Profile and Broad Protection

Preclinical data indicate that DIFF-flu (search)Search drug offers a differentiated safety profile with negligible viral shedding and significantly reduced viral loads in respiratory tissues. This suggests the potential to extend nasal spray vaccine eligibility to older adults and other underserved groups who are currently excluded from existing nasal spray vaccination programs.

Notably, preclinical studies demonstrate that DIFF-flu (search)Search drug confers 100% protection against epidemic strains circulating more than 50 years ago while also eliciting strong immunity against contemporary variants, indicating robust cross-protective capabilities.

Addressing Global Influenza Burden

The approval comes at a critical time when seasonal influenza continues to pose a significant global health challenge. According to the World Health Organization, seasonal influenza infects up to 1 billion people each year, causing 3-5 million severe cases and 290,000-650,000 respiratory deaths globally.

Older adults account for the majority of influenza-related deaths and face heightened risks of complications including pneumonia, myocarditis, encephalitis, and acute cardiorespiratory failure. Studies demonstrate that influenza vaccination can reduce hospitalization risk by 40-60%, making improved vaccine coverage especially critical for aging and medically vulnerable populations.

Despite these benefits, vaccination rates remain suboptimal worldwide. In China, influenza vaccination coverage is approximately 3.8%, far below mature markets such as the United States at around 49.3%. This low uptake underscores the need for more accessible and acceptable vaccination options.

Market Evolution and Future Opportunities

The global influenza vaccine market is undergoing structural evolution, with nasal spray vaccines representing an increasingly important direction for influenza prevention. These vaccines induce mucosal immunity directly at the site of viral entry, offering advantages over traditional injectable vaccines that face challenges including suboptimal uptake and limited ability to curb viral transmission.

A significant regulatory development occurred in September 2024 when the U.S. FDA granted authorization for at-home administration of a nasal spray influenza vaccine, paving the way for direct-to-consumer distribution models. This milestone significantly improves convenience and accessibility for the public and creates favorable conditions for DIFF-flu (search)Search drug's future global introduction.

Company Innovation Platform

DIFF Biotech (search)Search term operates as a clinical-stage biotechnology company specializing in its proprietary Viraltech Architect Platform, which enables integrated, end-to-end development of differentiated biologics. The company has filed over 70 domestic and international invention patents, including more than 10 PCT applications, and has received multiple honors including the 23rd China Excellent Patent Award.

The company's research and development efforts span mucosal vaccines, antiviral drugs, oncolytic viruses, and gene therapy products. Its vaccine pipeline, powered by proprietary attenuation technologies, effectively establishes the body's first line of defense at the mucosal barrier, offering clear competitive differentiation in the respiratory infectious disease prevention space.