AstraZeneca COVID-19 vaccine nasal spray effective in animals, NIH says

Researchers at the National Institutes of Health said a COVID-19 intranasal vaccine has proven effective in hamsters and monkeys.

The team, lead by Dr. Vincent Munster of NIH’s National Institute of Allergy and Infectious Diseases, tested the Oxford/AstraZeneca nasal spray vaccine and published its results on July 27 in the journal Science Translational Medicine.

"All COVID-19 vaccines now in use are injected into the muscle," the NIH said in a statement. "Intramuscular injection produces antibodies that circulate in the blood to recognize the virus. But this route of administration doesn’t necessarily produce antibodies in the nose and nasal passages."

Scientists hope an intranasal vaccine will be able to block the coronavirus from entering the nasal passages and bloodstream.

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The researchers said they both sprayed the vaccine intranasally and injected the vaccine in hamsters. Results revealed both methods produced high levels of antibodies in a single dose, but the intranasal spray produced higher levels of antibodies in the blood. 

The vaccinated hamsters and a group of unvaccinated animals were then exposed to COVID-19. The vaccinated hamsters — either through the spray or the syringe — were protected from the disease, researchers said. Meanwhile, the unvaccinated hamsters suffered severely from a COVID-19 infection, including loss of weight and lung damage, according to the study.

Researchers replicated the method in monkeys and received the same promising results. Some of the unvaccinated monkeys developed pneumonia after being exposed to COVID-19.

NIH said more research is needed, and a clinical trial with human volunteers using the intranasal spray is underway at the University of Oxford. 

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Currently, the AstraZeneca vaccine is not available in the U.S. 

AstraZeneca said it intends to seek U.S. approval for its injected COVID-19 vaccine later this year, further delaying the application even as the company announced it had already delivered more than 1 billion doses to other countries.

The Anglo-Swedish drugmaker said the application has been delayed because it has decided to ask the U.S. Food and Drug Administration for full regulatory approval, rather than the fast-track emergency use authorization originally anticipated. As part of this "biologics license application," the FDA has requested extensive data from clinical trials around the world, as well as data on real world use of the vaccine.

Plans for AstraZeneca’s U.S. application are being closely watched because the timetable has slipped in recent months. When AstraZeneca released data from its U.S. vaccine trial on March 22, company officials said they expected to seek FDA authorization in April.

Among the concerns AstraZeneca will have to address are reports that the vaccine may be linked to rare blood clots, which have caused some countries to limit its use in younger people.

The Associated Press contributed to this story. This story was reported from Los Angeles.