Currently, there are only eight (8) nasal spray vaccines for Covid-19 out of the 108 vaccines going through clinical trials. The rest are administered intramuscularly.
Since the Covid-19 virus is a virus affecting the respiratory system, it enters the body nasally. This is also the main reason why swab tests are done through the nose.
According to two immunologists from the University of Alabama, nasal spray Covid-19 vaccines provide more benefits against the virus.
It is explained that this kind of Covid-19 vaccine comes in contact with the virus at the infected area before it goes further into the body. Therefore, many believe that the Covid-19 vaccine nasal spray is promising. Continue reading to understand more about this.
What Do Nasal Spray Vaccines Do?
Nasal spray vaccines are made to provide immunity in the nasal mucosa. The mucosa is the tissue that protects the lungs, nose, and mouth. This is the deepest layer that absorbs and secretes. It has thin connective tissue and epithelium cells. Moreover, it has special goblet cells designed for the secretion of sticky mucus in the gastrointestinal tract.
Many experts believe that this area is where the Covid-19 virus enters before it goes to the lungs. The main point of nasal vaccines is to create barriers so that respiratory viruses cannot enter further.
Image source: grey_and / Shutterstock
What Happens to the Mucosa and the Lungs When Nasal Vaccines Are Used?
According to research done on animal figures, nasal vaccines activate IgA or immunoglobulin A, NAbs or systemic neutralizing antibodies, and T-cell reactions in the lungs. When there is a presence of NAbs, it shows that protective immunity is highly likely. “Titres” is used in measuring this. There is better protection with a higher titer.
A single dose of Covid-19 nasal vaccination provides mucosal and systemic immunity from the virus. There is evidence from genetic sequencing that there is coordination in activating T/B-cell reactions in lymphoid tissues connected with the nose. Moreover, the provided immunity is stronger. Infection is controlled, and transmitting the disease is prevented.
How Does Nasal Mucosa Prevent the Transmission of Covid-19?
Nasal IgA is activated when the virus enters the nasal cavity. The infection is often seen to start in the nasopharynx. That is why CoVid-19 nasal spray vaccines are seen to significantly lessen the viral load in the nasal mucosa, which is the main entry of the virus.
How Can Nasal Spray Vaccines Stop the Spread of Covid-19 Virus?
According to specialists, Covid-19 nasal spray vaccines can do a lot in curbing the pandemic if used together with the approved vaccines administered intramuscularly.
Daniel Oran and Eric Topol from the Scripps Institute published their idea in Scientific American in March 2021 about this. Aside from monetary benefits, they stated the other reasons why many want to use Covid-19 nasal spray vaccines. First, it is easy to administer, removes the problem with people who are afraid of needles, provides fast immunity in the mucosa, and lessens the viral load and transmission of the virus.
The Conversation released an article about needle phobia and how it is related to the virus. It states that in the UK, 10% of the people are hesitant to get the vaccine because of this. 25% of Americans are hesitant in getting an injection. Moreover, recent research says that people who have needle phobia are more likely to feel hesitant in getting the vaccine.
Vaccines administered nasally have shown success in giving protection against the virus causing influenza or flu virus. The concept of choosing this kind of vaccine to protect the respiratory tract has been practiced for a long time. For instance, the US FDA or Food and Drug Administration has developed LAIV or live attenuated influenza vaccine in the 1960s.
Although it is promising, the main problem is finances. Therefore, nasal spray vaccines need to be proven for their safety and efficacy in clinical trials. The 3rd phase of the clinical trials is crucial since many participants are needed. As a result, financial support from the government, investors, and philanthropists is required. Compared to intramuscular vaccines, nasal vaccines have not seen many developments.
Natural Infection and Vaccination: Which is More Effective?
Is vaccination less effective than a natural infection? There is no definite answer for this. According to evidence, natural infection draws out a wider immune response to the whole virus compared to mRNA vaccines and others. Put simply; the study shows that natural infection is better in giving protection than vaccination.
However, in a study, hybrid vaccination, which means giving a booster shot to the person infected with the virus before, has way more protection compared to natural infection alone.
Approval of Nasal Spray Vaccines
There was an approved nasal vaccine by the US FDA in 2003, which is FluMist. This nasal spray vaccine for flu is the result of the 4-decade research of Prof. Hunein Maassab from the University of Michigan.
Nevertheless, it is not definite if Covid-19 nasal vaccines are favored or not. Most of the $12.4 billion budget for research and development was spent on intramuscular vaccines. Scientists think now that the big Covid-19 IM vaccines such as Johnson & Johnson, Moderna, and Pfizer are likely not enough.
Dr. Navin Varadarajan, a professor from the University of Houston’s Chemical and Biomolecular Engineering, mentioned that there is no mucosal immunity with the currently-approved vaccines being administered now. Many systemic vaccines’ blind spots are the areas in the upper nostrils.
Dr. Daniel Teres and Martin A. Strosberg mentioned in an article released on September 5, 2021, that although serious and critical effects of the symptoms have been blocked successfully, getting the normal life back does not happen yet. The economy is still falling, hospitals are still full, healthcare is almost collapsing, and people are suffering and dying.
Dr. Teres, who is a critical care doctor and public health and community instructor from the Tufts University School of Medicine in Boston, is not convinced that the Covid-19 nasal vaccine is the new method for Covid-19. He said that private sectors, governments, and philanthropists should spend more on clinical trials to create Covid-19 nasal vaccines so that their efficacy can be proven better.
Researchers from the NIH’s National Institute of Allergy and Infectious Diseases or NIAID did a test on hamsters and monkeys by giving the Oxford/AstraZeneca vaccine nasally to these animals. The results of their study, led by Dr. Vincent Munster, were released in Science Translational Medicine on July 27, 2021.
They did the test first on hamsters by comparing the vaccine administered nasally and then intramuscularly. After one (1) dose, the researchers saw that high levels of antibodies were produced in the blood in both vaccine routes. After administering the vaccine nasally, they discovered that the antibody levels in the blood were higher.
When the vaccinated hamsters were exposed to the virus directly through their nose or other infected hamsters, both vaccine routes also provided protection for the hamsters from the serious effects of the disease. Hamsters that were unvaccinated had signs of lung damage and lost weight. Vaccinated hamsters did not suffer from these.
The researchers did the test next on four (4) monkeys. Similar results were seen with them. After the second dose, the antibodies in their blood were similar to people who recovered from the virus. When they were exposed to the virus, monkeys who got the Covid-19 nasal vaccine had less of the virus in their noses and lung tissues. 3 of the unvaccinated animals showed signs of pneumonia, and none of the vaccinated monkeys suffered from these.
Though the results of this study are favorable, further research is still needed on the Covid-19 immunity received nasally and intramuscularly. Dr. Munster mentioned that more tests need to be conducted on people for the administration of the vaccine nasally.
Storage of Covid-19 Nasal Spray Vaccines
Standard home refrigerators can be used to store nasal spray vaccines making storage for these vaccines easy. Gavi, the Vaccine Alliance, released an article in March 2021 regarding the other benefits of nasal vaccines.
Aside from not requiring special refrigeration for storage, they mentioned that this kind of vaccine does not need to be administered by a health professional. They are also more preferred by millions of people who are afraid of needles.
The Status of Human Trials of Covid-19 Nasal Spray Vaccines
DelNS1-2019-nCoV-RBD-OPT1 is one of the most advanced in the clinical trials of nasal vaccines. This vaccine utilizes a flu-based receptor binding domain created with Xiamen University, Beijing Wantai Biological Pharmacy, and the University of Hong Kong. The WHO reported that the vaccine is in the second phase of the clinical trials.
NONS or Nitric Oxide Nasal Spray was officially launched in early 2021 by SaNOtize Research and Development for the Covid-19 virus. The Vancouver-based Israeli-Canadian firm launched this with the name Enovid in Israel in partnership with Nextar Chempharma Solutions Ltd.
SaNOtize announced recently the results of the clinical trials conducted in the CK for their vaccine. It was found to be effective in the prevention of transmitting Covid-19 and lessen its duration and the severity of the symptoms of infected patients.
SaNItize has registered this nasal spray vaccine in New Zealand through the New Zealand Medicines and Medical Devices Safety Authority. They have been granted permission to distribute and sell the vaccine all over the country.
Bharat Biotech Intl Ltd.
Bharat Biotech submitted a proposal in July 2021 to the Drugs Controller General of India or DCGI. They requested for the Phase 1 trials of their Covid-19 nasal vaccine to be conducted/
Scientists from the Washington University’s School of Medicine demonstrated their Covid-19 nasal spray vaccine. It utilizes an adenoviral spray that boosts the mucosal immunity of chimpanzees in a published study in Cell in August 2020.
Through the carrier called ChAd-SARS-CoV-2, the vaccine increased and intensified the mucosal B- and T-cell reactions in the chimpanzees. Moreover, the scientists found that infections in the upper and lower respiratory tract are prevented.
CanSino, from China, released the phase 1 clinical trial results of the aerosol form of their Ad5-nCoV on July 26, 2021. Ad5-nCoV has already received approval as an intramuscular vaccine. Since the vaccine has already been approved to be administered intramuscularly, the company hopes the authorization for the nasal spray version will be easier to obtain.
AuraVax Therapeutics, a biotech firm in the US, is working on manufacturing NanoSTING, their own nasal Covid-19 nasal spray vaccine. They plan to coordinate with the FDA regarding the beginning of the first phase of human trials of this vaccine in May or June 2022.
Covi-Vax, a single-dose nasal vaccine, began its first phase of the clinical trial. This vaccine by Codagenix utilizes an attenuated live virus instead of using virus particles or an antigen as a base. The company utilizes a component of the viral genome that is seen as a safer method against Covid-19.
Finland’s Nasal Shot
A non-replicating viral vector is used for this nasal spray vaccine. The University of Eastern Finland and the University of Helsinki developed this vaccine.
Countries that Have Approved the Selling of Covid-19 Nasal Spray Vaccines
- New Zealand
Israel and New Zealand granted interim approval in March 2021 to sell nasal spray vaccines for Covid-19. SaNOtize also distributed Enovid in Bahrain in July 2021.
Obstacles of the Covid-19 Nasal Spray Vaccine
Finally, you have a better understanding of everything there is to know about nasal sprays against Covid-19. Even though these vaccines are promising and possibly beneficial, the effectiveness is complicated. That is because it might be limited if the person has been exposed to the virus. The immunity acquired from the virus might destroy the vaccine.
Dr. Troy Randall, an inflammation, immunology, and immunotherapeutics researcher from the University of Alabama, said that giving mRNA-based vaccines nasally is likely. However, there can be changes needed to the Covid-19 nanoparticles, which are found in the injectable form of the vaccine. He also added that it needs to be formulated for the epithelial cells in the nasal area to absorb and affect the immune system.
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