A trial to see if an inhaled coronavirus vaccine would be more effective than one delivered via injection is starting in the U.K.
A small trial of 30 people will see participants inhale either the Oxford Vaccine, which is currently being developed by AstraZeneca and in the Phase III of testing, or the saRNA vaccine by Imperial College London, U.K. It is thought that by targeting the airways directly, which is one of the main entry points for the virus, the vaccine could produce a stronger immune response.
If this is the case, scientists could look at inhalation as an alternative method for vaccine delivery. Being able to deliver via inhalation could expand the number of people able to be vaccinated.
Project leader Chris Chiu, from Imperial College London, said there is evidence to suggest that flu vaccines delivered via a nasal spray can help protect people from influenza, so they are looking to see if this is the case for SARS-CoV-2, the virus that causes COVID-19.
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“The current pandemic is caused by a respiratory virus which primarily infects people through the cells lining the nose, throat and lungs,” he said in a statement. “These surfaces are specialized and produce a different immune response to the rest of the body, so it is critical we explore whether targeting the airways directly can provide an effective response compared to a vaccine injected into muscle.”
In the inhalation trial, 30 people will be recruited. For both vaccines, participants will be split into groups, with one group either receiving a low, medium or high dose of the vaccines. The other group will be given the vaccines at the optimal dose. Previous research has suggested vaccines delivered directly to the respiratory tract require lower doses than through injections into muscle.
Participants will have blood and nasal samples analyzed and they will undergo bronchoscopies to get samples from deeper in the lungs. The blood samples will be checked for antibodies against SARS-CoV-2. Nasal samples will be checked for specialized antibodies called IgA that would indicate the vaccines had elicited a more localized immune response.
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“This study will tell us whether the two frontrunner vaccines in the U.K. for COVID-19 would be as effective if administered by inhalation rather than an injection,” Fiona Watt, Executive Chair of the Medical Research Council, said in a statement. “It will be interesting to see whether an inhaled version of the vaccine might offer a more immediate form of protection and whether it would have advantages in terms of making a vaccine available to large numbers of people. We eagerly await the results of the study.”
Robin Shattock, who is leading the research on Imperial’s saRNA vaccine, said that while scientists across the world are working to develop vaccines, most trials will not provide any information on whether they prompt a localized response in the nose, throat and airways.
“It may well be that one group has the right vaccine but the wrong delivery method, and only trials such as this will be able to tell us that,” she said in a statement. “We look forward to assessing different delivery methods and pushing forward the global scientific effort against this virus.”
The Oxford vaccine trial was recently halted after one of the participants became ill. It has since resumed and AstraZeneca’s chief executive Pascal Soriot said it is still hopeful the vaccine will be ready by the end of the year. “I still think we are on track for having a set of data we would submit before the end of the year and then it depends how fast regulators will review it and give approval,” he told the Financial Times.
Sarah Gilbert, who is working on the Oxford vaccine, said the team has already shown the drug is safe and produces a strong immune response via injection. “Delivering the vaccine to the respiratory tract instead may be a good approach to inducing immune responses in the best place to enable a rapid response after exposure to airborne virus,” she said.
