How the nasal COVID-19 vaccine helps prepare for infection at the onset of infection

Imagine inhaling just a few drops of liquid or mist to protect against COVID-19. That is the idea behind the nasal COVID-19 vaccine, Has been attracting attention recently As a spray or liquid. These nasal vaccines are based on the same technique as regular vaccines given by injection.

but, Mayuresh AbhyaankarResearchers at the University of Virginia, who are studying infectious diseases and working on nasal vaccines, say that vaccination of someone where the coronavirus is likely to launch an attack has many immunological benefits. Explaining.

1. What is a nasal vaccine?

Nasal vaccines, as the name implies, are given nasally. More precisely, these vaccines, called intranasal vaccines, are liquids that can be administered as a spray or through a dropper or syringe.The The most common nasal vaccine is FluMistNasal drops that use the inactivated influenza virus to protect against influenza.The intranasal vaccine may be a weakened live virus, similar to the nucleic acid vaccine FluMist. Like mRNA coronavirus vaccine Or a protein vaccine like the hepatitis B vaccine or CorbeVax coronavirus vaccine..

read more: Analysis: Boosters are important, but an improved COVID vaccine will be the key to ending a pandemic

Intranasal vaccines are ideal for protecting against nasal pathogens such as influenza and coronavirus. These vaccines help train a person’s immune system at potential infections by mimicking the first steps of natural exposure to airborne pathogens.Scientists say that the first immune response of the airways after a person is exposed to an aerial virus Affects how people get sick..Therefore, in theory, intranasal vaccines Providing better protection Than the vaccine given through a shot in the arm.

2. How does the coronavirus infect people?

Immediately below these cells in the mucosa are many types of immune cells that form so-called immune cells. Mucosal immune system.. The cells of the mucosal immune system first identify the invading coronavirus particles and initiate a defensive response. SARS-CoV-2, the virus that causes COVID-19, normally enters the body through the nose and lands on the mucous membranes. Behind the nasal passages and in the throat. The virus then invades the cells it comes in contact with, replicates and spreads.

For unvaccinated individuals, it will take about Two weeks for these immune cells to build a protecting response After encountering the coronavirus. By that time, the virus can easily infect other parts of the body, such as the lungs. Leads to severe illness..

Nasal vaccines follow many of the same steps. When inhaling a nasal vaccine, the particles land on the mucous membranes of the nasal passages or the back of the throat, enter cells in those places, and provoke an immune response. This process teaches the body about the coronavirus and makes it possible to deal with real infections in the future.

3. How is the nasal vaccine different from the intramuscular vaccine?

When you receive an injection of COVID-19 in your arm, the vaccine provokes a strong immune response in cells near where you received the injection. It also causes your immune system to produce some coronavirus-specific antibodies and other immune cells elsewhere in your body.

When the coronavirus begins to infect cells in the human respiratory tract, nearby immune cells begin to defend.Your body too Send antiviral immune cells and antibodies From other places to the site of infection. However, by the time enough coronavirus-specific immune cells have gathered around the site of infection to prevent the virus from replicating, the virus has already begun to spread throughout the body, making it difficult for the immune system to catch up.

Nasal vaccine mimics the virus Prepare your immune system against the virus, Like any other vaccine. But importantly, they also mimic the process of infection, Mucosal immune system of the nose and throat.. Simply put, an intranasal vaccine is like recognizing that an invasion will occur and placing security guards in the right place before the problem occurs.

Science supports this idea.In a direct comparison, AstraZeneca’s COVID-19 vaccine was provided Enhanced protection for hamsters vaccinated in the nasal passages Compared to those vaccinated intramuscularly.

Intranasal vaccination can also be used in combination with intramuscular immunity. In a recent study, my colleague and I gave some mice both a nasal and intramuscular vaccine and were exposed to a lethal dose of SARS-CoV-2 – 100% of these combined vaccinated mice survivedCompared to only 10% of unvaccinated mice. We are currently testing whether this mixed approach is superior to the intranasal or intramuscular approach alone.

Finally, intranasal vaccines are painless, non-invasive and do not require special training to use.

Nasal vaccines, such as the liquid flu vaccine that nurses give patients here, are easy to administer and do not require a needle, but it can be difficult to ensure that the full dose is absorbed.CDC / Douglas Jordan via Wikimedia Commons

4. What are the risks of a nasal vaccine?

Nasal vaccines can be more difficult to correct than injections, especially in young children. If someone has a stuffy nose or sneezes a portion of the vaccine before it is completely absorbed, it can be less than the desired dose.

There are also some unique health risks. All vaccines have undergone rigorous safety and clinical trials, but these processes are especially important for nasal vaccines due to the simple fact that the nose is close to the brain. In 2000, 27.7% of people vaccinated with inactivated intranasal influenza vaccine in Switzerland Onset of transient facial paralysis – Also known as Bell’s palsy. Researchers later discovered that the cause was a bacterial toxin added to the vaccine to boost the immune response.

This is the only reported neurological problem caused by an intranasal vaccine, but there are some things to consider.

5. How long does it take to get the intranasal COVID-19 vaccine ready?

As of late May 2022, there are no approved COVID-19 intranasal vaccines for human use.Currently 7 in clinical trialsAnd three of them (manufactured by Beijing Wantai Biological Pharmacy, Bharat Biotech, and Codagenix and Serum Institute of India) In Phase 3 human exams..

Within the next few months, the results of these trials will show not only how safe these promising new vaccines are, but also whether they are superior to the vaccines currently in use.

This article will be republished from conversation Under a Creative Commons license.read Original work..