Yale University researchers reported a technology to deliver mRNA vaccines in the nose, not a way to remotely vaccinate people
Intranasal delivery of vaccines is expected to provide better immunity against respiratory diseases such as COVID-19 and are easier to administer. Some are already being used against the flu. Researchers from Yale found a way to administer mRNA vaccines in mice by applying droplets of vaccine directly into the animals’ nostrils, eliciting an immune response against SARS-CoV-2.
Factually inaccurate: The study from Yale University didn’t show that mRNA vaccines can be delivered through the air. Rather, it showed that droplets of mRNA vaccines applied directly onto the nostrils of mice were able to reach the lungs and generate immune protection against SARS-CoV-2.
Misleading: The study from Yale University provides encouraging evidence on developing nasal mRNA vaccines and drugs. It doesn’t contain elements or comments suggesting that this technology could be used to disseminate vaccines into the air and remotely vaccinate people inhaling it.
Researchers from Yale University, published a study in August 2023 on a new technology for mRNA vaccine delivery. In early September 2023, a video from the Epoch Times claimed that this technology could be used to “disseminate the [COVID-19] vaccine quietly in a way that people wouldn’t even realize that they were getting vaccinated”.
In the video, Epoch Times anchor Roman Balmakov acknowledged that it was “just speculation”, yet added that “it’s really not a stretch to imagine that if these aerosol vaccines do develop to the point of being viable at a large enough scale, they could theoretically be deployed without the American citizens being told about it”. A version of that claim, using excerpts from the Epoch Times video, also circulated on social media affirming that Yale researchers had “created a new delivery method for mRNA vaccines…Through the air”.
Taken together, these statements implied that the results from the Yale researchers were a significant step toward an effective remote, airborne vaccination system. However, this misrepresents the study.
What did the study show?
Intranasal delivery has several advantages over the conventional intramuscular route used for most COVID-19 vaccines so far. First, it delivers the vaccine right into the areas—the nose and lungs—that respiratory viruses like SARS-CoV-2 primarily infect. Immunization in these areas would ensure a swift immune response as soon as SARS-CoV-2 enters the body.
Second, intranasal delivery with a spray is less invasive than using a needle. This would offer greater flexibility—since people could potentially perform the vaccination themselves. It would also reduce possible risks inherent to injections like shoulder injuries, and make the experience less stressful for people afraid of needles.
In line with scientific efforts to improve vaccine administration, Suberi et al. aimed to engineer an intranasal mRNA COVID-19 vaccine delivery system. Suberi and colleagues used a different mixture of molecules to encapsulate the mRNA compared to the Moderna and Pfizer-BioNTech mRNA vaccines administered intramuscularly.
The researchers then administered droplets containing the encapsulated mRNA into the nostrils of mice. They later observed that the mRNA reached the mice’s lungs and entered the cells. They also observed that mice that received the mRNA via the nasal droplets mounted a better immune response against SARS-CoV-2 than mice that didn’t receive the mRNA.
Why the claim exaggerated the study’s results
Contrary to the claim, Suberi and colleagues didn’t administer vaccines “through the air”. As mentioned above, they loaded drops containing the mRNA directly onto the nostrils (also called nares) of mice. This is a description of the technique from a pre-publication version of the study:
“[M]ice were anesthetized under 3% isoflurane, the mouth was held closed and 50 [microliters] polyplex solution was pipetted onto the nares of the animal. The mouth was held closed until no visible liquid droplet remained on the nares, approximately 5 breaths.”
As the method described above would illustrate, the vaccine isn’t disseminated “through the air”. Contrary to the Epoch Times’ video title, the researchers didn’t create an aerosol. Aerosols are microscopic droplets that can linger in the air longer and travel over longer distances than larger, heavier droplets. On the contrary, Suberi et al. simply deposited a 50 microliter (a microliter is a millionth of a liter)-drop of liquid in the animals’ noses. This technique doesn’t permit the dissemination of aerosols in the air to effectively vaccinate people remotely, since it requires depositing liquid directly onto the nose with a pipet.
To disseminate vaccines through the air, several important technical challenges need to be overcome. For example, how to turn the liquid containing the encapsulated mRNA into aerosols and how would that affect the stability and effectiveness of the vaccine? How would the droplets of encapsulated mRNA react in the air? Would they dry out, or get oxidized by the oxygen in the air? How far would they travel? How would exposure and dose be controlled, considering that they would be subjected to air turbulence or wind?
The study by Suberi et al. didn’t contain any information that would allow us to address these questions. Despite the absence of information that would bridge this gap, the Epoch Times still considered their claim as “really not a stretch”, without providing supporting evidence that such a feat could be achieved with incremental improvements of the technology presented by Suberi et al. Furthermore, nasal vaccines are already routinely used against the flu and haven’t been used or improved into remote mass vaccination devices.
- 1 – Suberi et al. (2023) Polymer nanoparticles deliver mRNA to the lung for mucosal vaccination. Science Translational Medicine.
- 2- Pilapitiya et al. (2023) Mucosal vaccines for SARS-CoV-2: triumph of hope over experience. eBioMedicine.
- 3 – Wang et al. (2021) Airborne transmission of respiratory viruses. Science.