The National Institutes of Health (NIH) has commenced a Phase 1 clinical trial to assess the safety and efficacy of a novel nasal COVID-19 vaccine, known as MPV/S-2P, across multiple locations in the United States. This trial marks a significant step in the development of next-generation vaccines that may offer enhanced protection against evolving SARS-CoV-2 variants.
Nasal Vaccine Design and Mechanism
The vaccine candidate, MPV/S-2P, employs a live-attenuated version of murine pneumonia virus (MPV), which is harmless to humans. This modified virus delivers a stabilized form of the SARS-CoV-2 spike protein, stimulating the body to recognize and combat the virus upon infection. Pre-clinical studies in non-human primates demonstrated that MPV/S-2P was safe, well-tolerated, and induced a strong immune response, both in terms of SARS-CoV-2 antibodies and within the epithelial cells lining the respiratory tract.
Dr. Reynold Panettieri, a professor of medicine at Rutgers University, explained that systemic vaccination might not be as effective as generating mucosal immunity in the nose and lungs. "When people can inhale the protein, in this case, the spike protein ... it actually builds up an immune response that's much more robust than that when it is injected."
Trial Design and Participant Criteria
The clinical trial aims to enroll 60 healthy adults, aged 18 to 64, who have previously received at least three doses of an FDA-approved mRNA COVID-19 vaccine. Participants will be divided into three groups, each receiving different dosages of the MPV/S-2P vaccine. Researchers will monitor the volunteers over a year to evaluate the vaccine's safety and its ability to elicit an immune response in both the nasal passages and the bloodstream.
Addressing Current Vaccine Limitations
Existing mRNA vaccines have shown diminishing efficacy over time, particularly in preventing transmission, even though they remain highly protective against severe COVID-19, hospitalizations, and deaths. Additionally, mRNA vaccines require complex manufacturing processes and ultra-cold storage, posing logistical challenges. A nasal spray vaccine could circumvent these issues, offering easier administration, potentially better protection, and improved storage and distribution capabilities.
Project NextGen and Future Availability
Dr. John Beigel, associate director for clinical research in the NIAID's division of microbiology and infectious diseases, noted that MPV/S-2P is part of Project NextGen, a collaborative effort between the Biomedical Advanced Research and Development Authority (BARDA) and NIAID. This project aims to advance 15 next-generation vaccines into Phase 1 clinical trials, with MPV/S-2P being the first.
Given the time required for clinical trials and FDA authorization, experts suggest that these nasal vaccines are unlikely to be available by the fall of 2024. However, with the reduced severity of COVID-19 infections in most healthy individuals, there is now sufficient time to conduct thorough safety and efficacy evaluations, ensuring the development of safe and effective therapies.
