A clinical trial of a nasal-spray version of the Covid-19 vaccine jointly developed by the University of Oxford researchers and AstraZeneca, in human beings, has failed and did not offer the desired protection.

Reuters quoted the University of Oxford as saying in a statement that, during the trial, only a minority of subjects reported an antibody response in the respiratory mucous membranes.

The immune response that was measured in the blood was found to be weaker, compared to a shot-in-the-arm vaccination.

In March last year, the University of Oxford announced the launch of the Phase I trial for investigating the delivery of the ChAdOx1 nCoV-19 coronavirus vaccine using a nasal spray.

The trial enrolled 30 healthy subjects to evaluate the immune system response levels generated by the vaccine using this delivery technique.

It was also launched for monitoring safety and any adverse reactions in the subjects.

AstraZeneca’s Covid vaccine was also developed with Oxford’s Jenner Institute scientists.

Chief investigator of the trial at the Jenner Institute Sandy Douglas said: “We believe that delivery of vaccines to the nose and lungs remains a promising approach, but this study suggests there are likely to be challenges in making nasal sprays a reliable option.”

In the AstraZeneca-funded trial, no safety concerns or serious adverse events were reported.

This June, AstraZeneca reported detailed results from the Phase III TACKLE clinical trial where Evusheld, a combination of two long-acting antibodies, was demonstrated to offer clinically and statistically significant protection against progression to severe Covid-19 or mortality from any cause a versus placebo.