The Oxford-AstraZeneca nasal vaccine has performed poorly in clinical trials

Since the early days of the pandemic, researchers have been working to develop a SARS-CoV-2 vaccine that can be injected in the form of a nasal spray because the spray is simpler than injection and could theoretically boost immune protection
when coronavirus enters the body.
Unfortunately, according to results published in eBioMedicine on Tuesday (Oct.
10), such an experimental vaccine, developed by scientists at the University of Oxford and AstraZeneca, did not perform well
in a small phase I clinical trial.
Researchers on the project say they plan to abandon the vaccine, at least in its current form
.

The purpose of the nasal approach is to enhance mucosal immunity, that is, the ability of the immune system to resist pathogens at mucosal contact points, rather than through circulating antibodies or immune cells
in the bloodstream.
The aim is to prevent more cases of COVID-19 than the vaccine, which is good at preventing severe illness and death, but cannot stop mild infections
.
However, the new findings suggest that less than half of the study participants developed detectable levels of mucosal antibodies one month after administration, and among those who did produce antibodies to the new coronavirus, the new coronavirus antibody levels were lower than those produced after injecting the vaccine or previous infection with the new coronavirus
.
Researchers at the University of Oxford said the results were not worth further testing, according to the Guardian, noting that one problem with this approach could be that many vaccines were accidentally swallowed and digested in the stomach before they
worked.

Lead researcher Sandy Douglas of the Jenner Institute at the University of Oxford said in a university press release: "The nasal spray did not perform as well
in this study as we had hoped.
Delivering the vaccine to the nose and lungs is still a promising approach, but this study suggests that making nasal sprays a reliable option can be challenging
.
”

In the trial, 30 unvaccinated volunteers received low, medium, and high doses of nasal vaccine, with 14 receiving a second dose of the same dose 28 days later and another 12 receiving the vaccine
3 to 7 weeks later.
The remaining participants received only the initial nasal dose
.
In addition, another 12 volunteers who had already received the vaccine were injected with nasal sprays as boosters
.
Although no safety concerns were identified, seven participants developed symptomatic SARS-CoV-2 infection
during the 4-month follow-up period following vaccination.

Other nasal vaccines show more promise: The Chinese government recently approved CanSino Biologics' nasal vaccine, which is a mist produced
by nebulizers.
Last month, the Indian government approved Bharat Biotech's vaccine, which can be drip into the nasal cavity
, Reuters reported.

Gordon Dougan, a vaccinologist at the University of Cambridge who was not involved in nasal vaccine research at Oxford and AstraZeneca, told the Guardian that the concept of a nasal vaccine against COVID-19 remained promising, adding that data from trials as well as Chinese and Indian vaccines could help experts find the best way to
conduct research.

"We need better science to understand how to induce immunity through nasal and oral administration," he said
.
"This is still not well understood
.
Nasal vaccines provide the opportunity to induce local immunity, potentially limiting transmission, which is essential
to prevent vaccine escape variation.
”