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A universal RNA vaccine effective against any strain of the virus has been developed
Last reviewed: 02.07.2025
Researchers at the University of California, Riverside, have presented a new RNA-based vaccination strategy that is effective against all strains of the virus and is safe even for infants and people with weakened immune systems.
Every year, scientists try to predict which four flu strains will dominate the coming season. And every year, people get an updated vaccine, hoping that scientists have identified the strains correctly.
The same situation is happening with COVID-19 vaccines, which are being adapted to combat the most common strains of the virus circulating in the United States.
This new strategy could eliminate the need to create different vaccines because it targets a part of the virus's genome that is common to all strains. The vaccine, its mechanism of action, and demonstration of its effectiveness in mice are described in a paper published in the journal Proceedings of the National Academy of Sciences.
"What I want to emphasize about this vaccine strategy is its versatility," said Zhong Hai, a UCR virologist and the paper's author. "It's applicable to many viruses, effective against all variants, and safe for a wide range of people. This may be the universal vaccine we've been looking for."
Vaccines typically contain either a dead or a modified live version of the virus. The immune system recognizes the virus protein and triggers an immune response, producing T cells that attack the virus and prevent it from spreading. It also produces "memory" B cells that train the immune system to defend against future attacks.
The new vaccine also uses a live, modified version of the virus, but does not rely on the traditional immune response or active immune proteins. This makes it safe for infants with immature immune systems and people with weakened immune systems. Instead, the vaccine relies on small RNA molecules to suppress the virus.
"The host — a human, a mouse, or any other creature — responds to a viral infection by producing small interfering RNAs (siRNAs). These RNAs suppress the virus," explained Shouei Ding, a UCR professor of microbiology and lead author of the paper.
Viruses cause disease because they produce proteins that block the host's RNAi response. "If we create a mutant virus that can't produce the protein that suppresses our RNAi response, we can weaken the virus. It will be able to replicate to a certain level, but then it will lose the fight against the host's RNAi response," Ding added. "This weakened virus could be used as a vaccine to boost our RNAi immune response."
To test this strategy on the mouse virus Nodamura, the researchers used mutant mice lacking T and B cells. A single shot of the vaccine protected the mice from a lethal dose of the unmodified virus for at least 90 days. Research suggests that nine days of a mouse's life is roughly equivalent to one human year.
There are few vaccines suitable for infants under six months. However, even newborn mice produce small RNAi molecules, which explains why the vaccine protected them. The University of California, Riverside, has already been granted a U.S. patent for this RNAi vaccine technology.
In 2013, the same research team published a paper showing that influenza infections also trigger our production of RNAi molecules. “So our next step is to use this same concept to create a flu vaccine to protect babies. If we’re successful, they won’t have to depend on their mothers’ antibodies anymore,” Ding said.
Their flu vaccine will likely be delivered in a spray form, since many people dislike needles. "Respiratory infections are spread through the nose, so a spray may be a more convenient delivery system," High said.
Furthermore, the researchers say it is unlikely that the virus will mutate to evade this vaccination strategy. "Viruses can mutate in areas not targeted by traditional vaccines. However, we target their entire genome with thousands of small RNAs. They will not be able to evade that," High said.
Ultimately, the researchers believe they can "cut and paste" this strategy to create a universal vaccine for any number of viruses.
"There are several known human pathogens: dengue, SARS, COVID. They all have similar viral functions," Ding said. "This strategy should be applicable to these viruses because of the easy transfer of knowledge."