Scientists have developed a needle-free mRNA vaccine that protects mice against COVID-19 and flu and causes less inflammation than conventional formulations, according to a new study published in The Journal of Clinical Investigation.
The vaccines use a high-pressure liquid jet to deliver genetic material directly through the skin, unlike the Pfizer-BioNTech and Moderna COVID-19 shots, which use lipid nanoparticles as the delivery system.
The authors — researchers from Rutgers University and Japanese institutions — reported that the technology generated strong immune responses and reduced viral replication in vaccinated mice.
The vaccine hasn’t been tested in humans, and researchers haven’t established whether it could reduce serious adverse reactions.
“Showing that a carrier-free, needle-free vaccine can be made protective opens a different design space than the one the field has been working in,” said study co-author Renata Pasqualini, Ph.D., a Rutgers researcher, in a university announcement.
COVID vaccines linked to serious adverse events
The study comes amid continuing concerns about COVID-19 vaccine injuries, and a study released this week comparing Pfizer and Moderna vaccine mortality rates.
The Centers for Disease Control and Prevention (CDC) has recognized a causal link between mRNA COVID-19 vaccines and myocarditis and pericarditis, particularly among adolescent and young adult males.
A 2022 study published in JAMA identified 1,626 reports meeting the CDC’s case definition for myocarditis following mRNA vaccination during the study period.
Reporting rates were highest among adolescent boys after their second dose, reaching approximately 106 cases per million Pfizer doses among males ages 16 and 17.
Symptoms of myocarditis can include chest pain, shortness of breath and an irregular heartbeat. Although many patients recover, some require hospitalization, and others have reported being permanently disabled.
Other documented serious adverse reactions include anaphylaxis following vaccination and a rare blood-clotting disorder associated with Johnson & Johnson’s COVID-19 vaccine.
The federal Vaccine Adverse Event Reporting System (VAERS) collects reports of suspected vaccine injuries and deaths. The latest figures show 1,678,901 adverse event reports following COVID-19 vaccination submitted to VAERS as of Sept. 25, 2026, including 39,260 reported fatalities and 29,299 reports of myocarditis or pericarditis.
The Rutgers study did not investigate whether its mRNA needle-free vaccine could prevent serious injuries.
