In studies conducted at Charite Medical University in Berlin, researchers evaluated a nasal vaccine, sCPD9, designed to guard against the SARS-CoV-2 virus. The findings indicated that this nasal formulation elicited a stronger immune response than some existing vaccines, with the study published in Nature Microbiology. The work explored how the mucosal route of administration could influence protection, especially at the primary sites where the virus enters the body.
The team conducted a head-to-head comparison between the intranasal sCPD9 vaccine and the Pfizer-BioNTech BNT162b2 mRNA vaccine, using Syrian hamsters as the preclinical model. Animals received two doses with a 21-day interval, administered through the nasal passages and spaced 21 days apart. After a two-dose course, the hamsters were exposed to the delta variant of SARS-CoV-2, assessing how well each vaccine could limit infection, viral spread, and disease progression. The researchers tracked both immune responses and practical outcomes, such as viral load, lung health, and signs of respiratory distress.
Results showed that the nasal vaccine provided superior protection against infection compared with the conventional mRNA vaccine in this model. Importantly, sCPD9 showed efficacy in reducing inflammation and preventing pneumonia, and the strongest protection was observed when animals received both vaccine modalities—nasal plus intramuscular—highlighting potential benefits of a combined vaccination strategy.
Traditional intramuscular vaccines primarily stimulate systemic neutralizing antibodies. While this helps prevent severe disease, it often does not optimally boost local immunity in the nasal mucosa and lung tissues where initial viral encounters occur. Mucosal antibodies play a critical role in limiting viral entry and subsequent transmission, offering an added line of defense that can complement systemic responses.
The scientists emphasize that these promising findings will need confirmation through human clinical trials to determine safety, dosing, and real-world effectiveness in diverse populations, including those in Canada and the United States. The study invites ongoing investigation into how nasal vaccines might be integrated with existing immunization programs to enhance protection against evolving variants and to curb transmission in communities at risk.”