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The nasal edition of the Oxford/AstraZeneca COVID-19 vaccine failed in an early-stage clinical trial, accelerating hopes for greater infection prevention and forcing researchers to reconsider the design.
Many experts have highlighted the possibility of nasal COVID-19 vaccinations. They argue that sniffing the injections can embed biting antibodies, namely IgA, and other immune defenses that can remove remnants of the SARS-CoV-2 virus into the nasal mucous membranes. before they have a chance to cause an infection. Currently, injections administered intramuscularly into the arms provide physically powerful systemic immune responses that prevent serious illness and death, but stimulate relatively low levels of antibodies in the mucous membranes and therefore do not prevent infection. .
Researchers at Oxford University had hoped to seamlessly adapt their existing COVID-19 vaccine for such an infectious schnoz spritz. The Oxford/AstraZeneca vaccine is a design based on a viral vector, which uses a weakened benign virus to send the SARS genetic code. -CoV-2 spike protein in human cells. The mild virus, in this case, is an adenovirus, a more productive type known to cause mild cold-like illnesses in humans, the express virus used in the vaccine moved away from chimpanzees. (This vaccine has not been legal in the United States, but is used in dozens of countries around the world. )
The researchers were lucky in preclinical trials with non-human primates, which developed strong mucosal antibody responses after nasal administration. But their hopes were dashed in the first clinical trial, the effects of which were published this week in the journal eBioMedicine. .
In the phase I trial of 42 other people, nasal management of the vaccine produced only modest mucosal antibody responses in only a few participants and also stimulated weaker systemic responses than intramuscular injections. The trial included another 30 people who had not been vaccinated before and 12 vaccinated other people who tried the nasal vaccine as a booster. Nasal management failed on either count. The only smart news is that no security issues were detected.
But, in even more disappointing results, the vaccine also gave the impression of being useless in preventing COVID-19. The small, early-stage trial is not designed to assess efficacy, but the researchers note that 7 of 42 participants reported SARS-CoV-2 infections after nasal vaccination. This is “discouraging for the prospect of long-lasting, physically powerful protection,” the Oxford researchers concluded in the published study.
In a press release, the trial’s lead researcher, Sandy Douglas of Oxford University’s Jenner Institute, put it mildly, saying, “The nasal spray did not work as well in this study as we had hoped. “
Douglas noted that the knowledge of researchers in China recommends more good luck with a vaccine administered with a nebulizer device, although the Oxford researchers noted that they were looking for more convenient control of nasal discharge. Douglas also noted that an intranasal vaccine has been approved in India, but knowledge of clinical trials on this vaccine has not yet been published.
Overall, Douglas said his study team would go back to the design stage, for example, proposing new formulations that could help the vaccine slide further through the nostrils and airways to prevent it from sliding into the stomach. The researchers also wondered if the adenovirus vector, eliminated from chimpanzees in the first place, may simply be bad at infecting human snouts. They also thought they were looking for larger doses.
While the effects of the trials are a setback for the cause, outdoor experts have suggested researchers not give up. The result is “disappointing,” infectious disease expert Andrew Freedman of Cardiff University said in a statement. , save more efforts to develop more effective intranasal vaccines to protect against COVID-19 and other respiratory infections. “
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