Stanford Develops Universal Nasal Spray Vaccine for COVID, Flu, and Pneumonia

How Does the Stanford Nasal Vaccine Work?

The vaccine concept builds on pioneering mucosal vaccine research led by scientists including Dr. Akiko Iwasaki at Yale University, who has demonstrated that mucosal boosting strategies can generate potent local immune responses in the respiratory tract. The Stanford team's approach uses self-assembling protein nanoparticles that display a carefully selected mosaic of conserved epitopes: the stem region of hemagglutinin from influenza, the S2 subunit of the SARS-CoV-2 spike protein, and conserved surface proteins from Streptococcus pneumoniae. By targeting these highly conserved regions rather than the variable domains that mutate rapidly, the vaccine aims to provide broad, variant-resistant protection.

Delivered as a nasal spray, the vaccine specifically targets the nasal-associated lymphoid tissue (NALT), which serves as the immune system's first line of defense for respiratory pathogens. Unlike traditional injected vaccines that primarily generate systemic IgG antibodies, nasal vaccination stimulates production of secretory IgA antibodies at mucosal surfaces — the actual site where respiratory infections begin. Research has shown this is a critical distinction: mucosal immunity can potentially block infection and reduce transmission, whereas systemic immunity primarily prevents severe disease after infection has already been established.

The nanoparticle platform incorporates an adjuvant designed to activate the STING pathway in mucosal immune cells. STING-activating adjuvants, including cyclic dinucleotides, have shown promise in preclinical studies for enhancing mucosal immune responses. The researchers are also working to achieve room-temperature stability for the formulation, which would eliminate the need for cold chain storage and dramatically improve distribution feasibility for global health applications — a significant advantage over current mRNA vaccines that require refrigeration or freezing.

What Do Early Clinical Results Suggest?

Early clinical testing of the nasal vaccine platform has involved healthy adult volunteers receiving two doses of the nasal spray several weeks apart, with researchers measuring safety, tolerability, and immunogenicity through nasal wash IgA titers and serum antibody responses. Preliminary results have been described as encouraging, with a substantial proportion of participants developing measurable nasal IgA antibodies against target pathogens.

This is consistent with findings from other intranasal vaccine programs. Multiple research groups worldwide have reported that intranasal delivery of protein-based and viral-vectored vaccines can elicit strong mucosal IgA responses along with tissue-resident memory T cell (TRM) responses in the nasal passages — a type of immune memory that provides rapid local protection upon re-exposure to a pathogen. Several intranasal COVID-19 vaccines have progressed through clinical trials in countries including India, China, and Iran, with some receiving emergency use authorization.

The safety profile of intranasal vaccines has generally been favorable across multiple programs. Common side effects typically include mild and transient nasal congestion, runny nose, sneezing, and mild headache. The nasal spray delivery format has consistently rated highly in acceptability surveys, with research suggesting strong patient preference for needle-free vaccination. Further clinical development is underway, with larger efficacy trials anticipated during the 2026-2027 respiratory season to determine whether the immune responses translate into meaningful protection against infection and disease.

Could This Replace Annual Flu and COVID Shots?

The potential to combine protection against three major respiratory pathogens into a single painless nasal spray represents an ambitious goal in vaccination strategy. Currently, adults are recommended to receive annual influenza and COVID-19 vaccines (both injections), and pneumococcal vaccines at specific intervals. Compliance with these recommendations remains suboptimal: CDC data show that fewer than half of US adults typically receive an annual flu shot, and COVID-19 booster uptake has fallen below 25%. The inconvenience of multiple injections, needle phobia (affecting approximately 25% of adults according to published surveys), and vaccine fatigue are significant barriers to adequate population-level immunity.

A single nasal spray addressing multiple pathogens could meaningfully improve vaccination rates. Survey data have consistently shown that a substantial majority of adults express greater willingness to get vaccinated when needle-free options are available, with even higher interest among those who report avoiding vaccines due to needle aversion. For children, the implications are also significant — nasal spray vaccines like FluMist have already demonstrated that needle-free delivery can reduce vaccination-related distress and potentially improve pediatric immunization rates in school-based settings.

Researchers estimate that if large-scale efficacy trials are successful, a combined nasal vaccine could potentially reach the market before the end of the decade, pending regulatory review. The manufacturing process is designed to use standard bioreactor technology compatible with existing vaccine production facilities. Several major global health organizations have expressed interest in supporting the development and distribution of mucosal vaccines for low- and middle-income countries, where respiratory infections remain a leading cause of death and cold chain storage poses significant logistical challenges.