New Delhi: As scientists and health researchers continue their search for an effective COVID-19 vaccine or therapeutic, new approaches are being explored. This includes nasal sprays for delivering vaccines via the nose. Recently, an expert panel of India’s drug regulator CDSCO recommended granting permission for phase 1 human clinical trial of Bharat Biotech’s nasal COVID-19 vaccine (BBV154). The Hyderabad-based vaccine innovator had said that its intranasal vaccine candidate for COVID-19 has shown unprecedented levels of protection in animal studies.
Meanwhile, scientists from Lancaster University in England and Texas Biomedical Research Institute in San Antonio have also reported that a nasal spray vaccine against COVID-19 has shown promise in animal testing. They said rodents that received two doses of the vaccine had antibody and T-cell responses that were strong enough to suppress SARS-CoV-2, the new coronavirus that causes COVID-19 disease. According to the researchers, the vaccine also reduced lung damage, inflammation and disease severity in the rodents.
What is a nasal vaccine?
A nasal vaccine is a vaccine administered to a person via the nose and does not require a needle. It induces immunity through the inner surface of the nose, a surface that naturally comes in contact with many airborne microbes, said Dr Srikanta J T, consultant – paediatric pulmonology, Aster RV Hospital, Bangalore.
Will nasal vaccine be a ‘game-changer’ in the fight against COVID-19?
Talking about the Bharat Biotech’s nasal vaccine candidate, NITI Aayog member (health) V K Paul said at a press conference that if BBV154 works against COVID-19, it can be a game-changer in the fight against the pandemic.
“It looks like an exciting development because potentially, yes, this route can be used to deliver the safe antigen against which an immunological response would happen. If it does work it can be a game-changer because it is so easy to use and we look forward to this development. Such a possibility is very plausible scientifically,” Dr Paul added.
Some experts believe that a nasal vaccine against the SARS-CoV-2 virus might do even better than a vaccine administered via the muscle. This is due to the fact that an intramuscular vaccine may help protect people from getting the disease or becoming severely ill, but individuals can still carry the virus in their nose that could spread to others. Scientists are yet to understand if most COVID-19 vaccines recently approved for restricted emergency use and that are currently under development can prevent the spread of the virus. An infection with the SARS-CoV-2 virus can take hold in the nose or throat, where the infection typically starts, before the systematic immunity kicks in.
Experts said a nasal vaccine, however, offers another kind of immunity that occurs primarily in the cells lining the nose and throat.
“You still get systemic immunity if you deliver it via the intranasal route, so that doesn’t go away, and you add a level of immunity that you don’t get with an intramuscular vaccine. And that immunity is local,” Frances Lund, an immunologist and vaccine developer at the University of Alabama, Birmingham, was quoted as saying by NPR.
Additionally, the study done by the researchers from Lancaster University in England and Texas Biomedical Research Institute in San Antonio noted that the vaccine completely protected the animals from shedding the virus which causes transmission of the virus, indicating that the nasal spray vaccine could help prevent people from spreading the virus.
“This means the immunization of the upper respiratory tract through a nasal spray can prevent individuals from spreading the virus and developing infections elsewhere in the body,” said study author Muhammad Munir, a Lancaster University virologist.
The research, which is yet to be peer-reviewed, has been published on preprint server BioRxiv.
Nasal spray COVID-19 vaccine a better option for children?
AIIMS Director Randeep Guleria recently said that a nasal COVID-19 vaccine will be easy to be administered to school-going children who bear a ‘very mild’ load of the disease but are infectious, news agency PTI reported.
“Vaccines for children may come later…Bharat Biotech is trying to get approved a nasal vaccine. Such a vaccine will be very easy to be given to children as it is a spray and not a jab and hence compliance is more. In half-an-hour, you can vaccinate an entire class. So, if that (nasal vaccine) is approved it will be even easier to give the vaccine (for COVID-19),” the renowned pulmonologist said in reply to a question.
When asked if a nasal spray against coronavirus is better than the shot, especially for kids, Dr Srikanta J T added: “Currently, COVID-19 vaccines that have been approved for emergency use or are being developed not have a live attenuated virus, i.e. a live virus that has been weakened not to cause side effects. This technology has been only employed for vaccination against seasonal flu, which has more or less the same efficacy as an injectable one. So whether it is better for children compared to injectable cannot be said at the moment.”
Advantages of a nasal spray vaccine
Experts said there are a number of advantages to nasal spray COVID-19 vaccine, including ease of self-administration and systematic immunity. A nasal vaccine is far less invasive for the recipient compared to an intramuscular injection option. According to the researchers, a nasal spray vaccine is an alternative for those who have blood clotting disorders or are scared of needles. A nasal spray vaccine will not only be simple to administer, but reduce the use of medical consumables like syringes and needles. What’s more, it could provide a low-cost alternative for the developing world as it may be easier to mass-produce using the same production technology for the flu vaccine.
Yet, despite the obvious advantages of intranasal vaccination and promising results seen in animal trials, human trials are still required to determine the safety and efficacy of nasal spray vaccine for COVID-19.