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Intranasal COVID-19 vaccine effective in animal studies
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At a Glance
•A nasal spray of the Oxford/AstraZeneca COVID-19 vaccine protected hamsters and monkeys against serious disease and reduced the amount of virus in the nose.
•Less virus in the nasal passages could decrease the risk that vaccinated people spread the virus, even if they don't feel sick.
•A clinical trial is underway to test intranasal vaccination in people.
https://www.nih.gov/news-events/nih-research-matters/intranasal-covid-19-vaccine-effective-animal-studies
The team first compared spraying the vaccine intranasally to intramuscular injection in hamsters. Both routes of administration produced high levels of antibodies against SARS-CoV-2 in the blood after a single dose. Levels of antibodies in blood were actually higher after intranasal administration.
Vaccinated hamsters and a group of unvaccinated animals were then exposed to SARS-CoV-2, either by direct administration into the nose or through contact with infected hamsters. Both routes of vaccine administration protected hamsters from serious disease. Unvaccinated hamsters lost weight and showed signs of lung damage, but vaccinated hamsters did not. The animals that received intranasal vaccination also had substantially less infectious virus in their nasal passages than unvaccinated animals.
The researchers next tested two doses of the intranasal vaccine in four monkeys. As in the hamsters, antibodies were found in the blood after the second dose, at levels similar to those seen in people who have recovered from COVID-19.
The monkeys were then exposed to SARS-CoV-2. Compared to four unvaccinated monkeys, those that received the intranasal vaccine had less virus in their noses and in lung tissue. Three of the unvaccinated animals tested developed symptoms of pneumonia, while none of the vaccinated monkeys did.
More work is needed to understand the differences in immune response between the two routes of administration. "But these results justify additional tests of nasal delivery for COVID-19 vaccines in people," Munster says.
Intranasal ChAdOx1 nCoV-19/AZD1222 vaccination reduces viral shedding after SARS-CoV-2 D614G challenge in preclinical models
Science Translational Medicine 27 Jul 2021
https://stm.sciencemag.org/content/early/2021/07/26/scitranslmed.abh0755
Abstract
ChAdOx1 nCoV-19/AZD1222 is an approved adenovirus-based vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) currently being deployed globally. Previous studies in rhesus macaques revealed that intramuscular vaccination with ChAdOx1 nCoV-19/AZD1222 provided protection against pneumonia but did not reduce shedding of SARS-CoV-2 from the upper respiratory tract. Here, we investigated whether intranasally administered ChAdOx1 nCoV-19 reduces detection of virus in nasal swabs after challenging vaccinated macaques and hamsters with SARS-CoV-2 carrying a D614G mutation in the spike protein. Viral loads in swabs obtained from intranasally vaccinated hamsters were decreased compared to control hamsters, and no viral RNA or infectious virus was found in lung tissue after a direct challenge or after direct contact with infected hamsters.
Intranasal vaccination of rhesus macaques resulted in reduced virus concentrations in nasal swabs and a reduction in viral loads in bronchoalveolar lavage and lower respiratory tract tissue. Intranasal vaccination with ChAdOx1 nCoV-19/AZD1222 reduced virus concentrations in nasal swabs in two different SARS-CoV-2 animal models, warranting further investigation as a potential vaccination route for COVID-19 vaccines.
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