In the past few days, two developments occurred in the research regarding respiratory diseases — one nasal drop to neutralise the pathogens in the nose and a nasal vaccine for Covid-19.
Published Sep 30, 2024 | 7:00 AM ⚊ Updated Sep 30, 2024 | 7:00 AM
How newly developed nasal spray and vaccine could enhance the fight against respiratory diseases.
The Covid-19 pandemic highlighted the devastating effects respiratory pathogens can have on humanity, resulting in the deaths of millions and inflicting financial and emotional distress on billions worldwide.
Most viruses enter the human body through the nose; when tiny droplets containing the airborne viruses of flu, Covid-19 or other infections are inhaled.
While healthy people breathe in these pathogen-containing droplets, they attach inside the noses and infect the cells that line the nasal passageways. These pathogens replicate and are released back into the air when infected individuals — whether they know it or not — sneeze, cough, laugh, sing, or simply breathe.
In the past few days, two developments occurred in the research regarding respiratory diseases — one nasal drop to neutralise the pathogens in the nose and a nasal vaccine for Covid-19.
While vaccines help combat these viruses, they are not foolproof. Vaccinated individuals could still be infected and be the carriers of the viruses. Even though useful, masks are not perfect either — due to chances of leakage and many people wearing them incorrectly or opting out of wearing them.
To better control and prevent respiratory diseases, research has developed a drug-free nasal spray that forms a gel-like matrix to capture and neutralise pathogens to provide an additional layer of protection against respiratory infections.
New research published in Advanced Materials introduces a novel nasal spray designed to prevent respiratory infections. This spray forms a protective layer in the nasal cavity, trapping airborne respiratory droplets and acting as a physical barrier against viruses and bacteria, while effectively neutralising them.
In studies conducted on mice, the Pathogen Capture and Neutralising Spray (PCANS) showed nasal retention for up to eight hours. In a severe Influenza A model, a single pre-exposure dose of PCANS resulted in a more than 99.99 percent reduction in lung viral titers. The treated mice achieved complete protection, whereas the untreated group showed no protection.
“PCANS has the potential to provide an extra layer of defence when traditional methods like masks and vaccines are insufficient,” Dr Nitin Joshi, corresponding author and Assistant Professor at Brigham and Women’s Hospital, Harvard Medical School said in a statement.
“With its broad-spectrum activity, it could protect against emerging variants of flu, RSV, Covid-19, and beyond,” Dr Joshi added.
Preclinical studies indicate that the spray is long-lasting and safe, and if validated in humans, it could play a crucial role in reducing respiratory diseases and bolstering public health against emerging threats.
“The Covid pandemic has shown us how rapidly respiratory pathogens can impact humanity. That threat is still with us,” Dr Jeffrey Karp, co-senior author said in a statement and added: “In addition to seasonal flu, we now also contend with Covid.”
“We need new, additional ways to protect ourselves and reduce the transmission of the disease,” Karp said.
The new study outlined the research team’s efforts to develop a nasal spray to protect humans against airborne respiratory illnesses. “The spray, named Pathogen Capture and Neutralising Spray (PCANS), was formulated using ingredients from the FDA’s Inactive Ingredient Database (IID), which have previously been utilised in approved nasal sprays, as well as compounds from the Generally Recognised as Safe (GRAS) list,” explained co-senior author Dr Joshi.
“We created a drug-free formulation using these components to block germs in three ways: PCANS forms a gel-like matrix that traps respiratory droplets, immobilises the germs, and effectively neutralises them, thereby preventing infection,” he added.
The researchers conducted their experiments in laboratory settings and have not yet tested PCANS directly in humans. They developed the formulation and assessed its ability to capture respiratory droplets using a 3D-printed replica of a human nose. The results showed that when sprayed into the nasal cavity replica, PCANS captured twice as many droplets as mucus alone.
They added that PCANS forms a gel that enhances its mechanical strength by a hundred times, creating a solid barrier and it blocked and neutralised nearly 100 percent of all viruses and bacteria they tested, including Influenza, SARS-CoV-2, RSV, adenovirus, K pneumoniae, and more.
Experiments on mice indicated that a single dose of the PCANS nasal spray could effectively prevent infection from the influenza virus (PR8) at 25 times the lethal dose. Virus levels in the lungs were reduced by over 99.99 percent, and the levels of inflammatory cells and cytokines in the lungs of treated animals returned to normal.
“The formulation’s ability to inactivate a broad spectrum of pathogens, including the deadly PR8 influenza virus, demonstrates its high effectiveness. In a rigorous mouse model study, prophylactic treatment with PCANS exhibited exceptional efficacy, with treated mice showing complete protection, while the untreated group did not benefit.” the authors said.
While the study does have limitations, including the absence of human trials for PCANS, it lays a solid groundwork for future research to explore the full potential of this nasal spray. The researchers are also investigating whether PCANS can block allergens, opening up a new avenue for allergy relief.
A recent study titled “An intranasally administered adenovirus-vectored SARS-CoV-2 vaccine induces robust mucosal secretory IgA” explored the efficacy of a new nasal vaccine designed to combat SARS-CoV-2.
The vaccine is an adenovirus-vectored formulation administered intranasally. This method aims to stimulate immune responses directly at the mucosal surfaces, which are critical for respiratory pathogens like SARS-CoV-2.
Participants, who had previously received two or three doses of inactivated whole-virus Covid-19 vaccines and had no prior SARS-CoV-2 infections, were administered two doses of NB2155 intranasally at 28-day intervals. The study aimed to evaluate the vaccine’s safety and its ability to induce nasal mucosal spike-specific secretory IgA (sIgA), which is thought to play a crucial role in protecting against infection.
The study demonstrated that the nasal vaccine elicited a strong mucosal immune response, particularly in the production of secretory IgA antibodies. These antibodies play a vital role in preventing viral entry at mucosal surfaces, suggesting that the vaccine could effectively block infection at the initial site of exposure.
In addition to mucosal immunity, the vaccine also induced systemic immune responses, including IgG antibodies, which are important for broader protection against the virus.
The research involved testing on animal models, where the vaccinated subjects showed significant protection against SARS-CoV-2 infection. This indicates that the vaccine could be effective in real-world scenarios.
The findings suggest that this intranasal vaccine could not only protect against Covid-19 but may also be adapted for other respiratory viruses, enhancing overall public health responses to respiratory infections.
“This is what I’ve been waiting for. It could finally give us a real end to the pandemic — no more waves of illness, no more rushing for tests and antivirals for the elderly or vulnerable. I hope this comes out soon!” said Kashif Pirzada Canada based Emergency Physician on X.
“I’ll explain why I think this is an important step. Living in 2024, we are constantly exposed to the virus. If you’re lucky, your immune system aborts the infection quickly. A fascinating paper published in Nature this June looked at infection dynamics in healthy volunteers. The authors developed three categories of infection: Sustained, Transient, and Abortive,” he said on X.
Out of 16 volunteers exposed to a controlled dose of the virus, six developed full-blown, sustained infections. Another three showed intermittent positive tests and were categorised as having Transient infections. Remarkably, seven volunteers didn’t develop an infection at all but exhibited signs of activation of their innate immune system.
“Their mucosal immune system (MAIT cells and APR+ ciliated cells) reacted and killed the infection before it could take hold — these were termed Abortive infections. You could be experiencing Abortive infections several times a year without knowing it, each time boosting your mucosal immune defences for the next encounter. However, if your ‘shields’ are down, you may end up with a severe infection and a higher risk of long-term complications,” said Pirzada.
“Clinically, I’ve observed that the duration of this immunity varies greatly. Some people get infected like clockwork every few months, some sooner, some later, and some not at all. The severity also differs — some have mild symptoms, while others are bedridden. This inconsistency likely explains why society struggles to reach a consensus on managing the virus,” he added.
If nasal mucosal vaccines can enhance that rapid-response immunity without the risk of a full-blown infection, that’s incredible news! “There are, however, significant challenges. This vaccine uses an adenovirus vector, similar to the Oxford/AstraZeneca vaccine, which had issues with clotting. Repeated use of the adenovirus vector can also lead to the development of antibodies that reduce its effectiveness. These vaccines have been stuck in trials for some time, which raises concerns,” he said.
But added if we get hard evidence that they work, it’s something to celebrate, and I’m excited to see more progress.
I’ll explain some of my reasoning of why I think this is an important step, and please correct me if I’m wrong here.
Just by living in the world of 2024, we are getting constantly exposed to the bug. If you’re lucky, your immune system aborts an infection quickly. There was… pic.twitter.com/5N9Jj9Iyen
— Kashif Pirzada, MD (@KashPrime) September 26, 2024
It should be also noted that Hyderabad based Bharat Biotech which developed the Covid 19 vaccine Covaxin is also developing a nasal vaccine — iNCOVACC – which is in the trial face.
(Edited by Muhammed Fazil)
