COVID-19 Nasal Vaccine Candidate Effective at Preventing Disease Transmission

Laurie Fickman wrote . . . . . . . . .

Breathe in, breathe out. That’s how easy it is for SARS-CoV-2, the virus that causes COVID-19, to enter your nose. And though remarkable progress has been made in developing intramuscular vaccines against SARS-CoV- 2, such as the readily available Pfizer, Moderna and Johnson & Johnson vaccines, nothing yet – like a nasal vaccine – has been approved to provide mucosal immunity in the nose, the first barrier against the virus before it travels down to the lungs.

But now, we’re one step closer.

Navin Varadarajan, University of Houston M.D. Anderson Professor of Chemical and Biomolecular Engineering, and his colleagues, are reporting in iScience the development of an intranasal subunit vaccine that provides durable local immunity against inhaled pathogens.

“Mucosal vaccination can stimulate both systemic and mucosal immunity and has the advantage of being a non-invasive procedure suitable for immunization of large populations,” said Varadarajan. “However, mucosal vaccination has been hampered by the lack of efficient delivery of the antigen and the need for appropriate adjuvants that can stimulate a robust immune response without toxicity.”

To solve those problems, Varadarajan collaborated with Xinli Liu, associate professor of pharmaceutics at the UH College of Pharmacy, and an expert in nanoparticle delivery. Liu’s team was able to encapsulate the agonist of the stimulator of interferon genes (STING) within liposomal particles to yield the adjuvant named NanoSTING. The function of the adjuvant is to promote the body’s immune response.

“NanoSTING has a small particle size around 100 nanometers which exhibits significantly different physical and chemical properties to the conventional adjuvant,” said Liu.

“We used NanoSTING as the adjuvant for intranasal vaccination and single-cell RNA-sequencing to confirm the nasal-associated lymphoid tissue as an inductive site upon vaccination. Our results show that the candidate vaccine formulation is safe, produces rapid immune responses – within seven days – and elicits comprehensive immunity against SARS-CoV-2,” said Varadarajan.

A fundamental limitation of intramuscular vaccines is that they are not designed to elicit mucosal immunity. As prior work with other respiratory pathogens like influenza has shown, sterilizing immunity to virus re-infection requires adaptive immune responses in the respiratory tract and the lung.

The nasal vaccine will also serve to equitably distribute vaccines worldwide, according to the researchers. It is estimated that first world countries have already secured and vaccinated multiple intramuscular doses for each citizen while billions of people in countries like India, South Africa, and Brazil with large outbreaks are currently not immunized. These outbreaks and viral spread are known to facilitate viral evolution leading to decreased efficacy of all vaccines.

“Equitable distribution requires vaccines that are stable and that can be shipped easily. As we have shown, each of our components, the protein (lyophilized) and the adjuvant (NanoSTING) are stable for over 11 months and can be stored and shipped without the need for freezing,” said Varadarajan.

Source: University of Houston

In Pictures: Food and Drinks of The Sun & The Moon Restaurant in Tokyo, Japan

Study: COVID-19 Virus Is Evolving to Get Better at Becoming Airborne

Results of a new study led by the University of Maryland School of Public Health show that people infected with the virus that causes COVID-19 exhale infectious virus in their breath – and those infected with the Alpha variant (the dominant strain circulating at the time this study was conducted) put 43 to 100 times more virus into the air than people infected with the original strains of the virus. The researchers also found that loose-fitting cloth and surgical masks reduced the amount of virus that gets into the air around infected people by about half. The study was published in Clinical Infectious Diseases.

“Our latest study provides further evidence of the importance of airborne transmission,” said Dr. Don Milton, professor of environmental health at the University of Maryland School of Public Health (UMD SPH). “We know that the Delta variant circulating now is even more contagious than the Alpha variant. Our research indicates that the variants just keep getting better at travelling through the air, so we must provide better ventilation and wear tight-fitting masks, in addition to vaccination, to help stop spread of the virus.”

The amount of virus in the air coming from Alpha variant infections was much more—18-times more—than could be explained by the increased amounts of virus in nasal swabs and saliva. One of the lead authors, doctoral student Jianyu Lai explained that, “We already knew that virus in saliva and nasal swabs was increased in Alpha variant infections. Virus from the nose and mouth might be transmitted by sprays of large droplets up close to an infected person. But, our study shows that the virus in exhaled aerosols is increasing even more.” These major increases in airborne virus from Alpha infections occurred before the Delta variant arrived and indicate that the virus is evolving to be better at travelling through the air.

To test whether face masks work in blocking the virus from being transmitted among people, this study measured how much SARS-CoV-2 is breathed into the air and tested how much less virus people sick with COVID-19 exhaled into the air after putting on a cloth or surgical mask. Face coverings significantly reduced virus-laden particles in the air around the person with COVID-19, cutting the amount by about 50%. Unfortunately, the loose-fitting cloth and surgical masks didn’t stop infectious virus from getting into the air.

Dr. Jennifer German, a co-author said, “The take-home messages from this paper are that the coronavirus can be in your exhaled breath, is getting better at being in your exhaled breath, and using a mask reduces the chance of you breathing it on others.” This means that a layered approach to control measures (including improved ventilation, increased filtration, UV air sanitation, and tight-fitting masks, in addition to vaccination) is critical to protect people in public-facing jobs and indoor spaces.

Source: University of Maryland School of Medicine

Salmon Soufflé

Ingredients

1 oz sticky rice
2 cloves garlic, peeled
1 large red chili
1-inch piece of galangal
1-inch piece lemongrass
9 oz fresh salmon fillet
1 tsp coconut milk
1-1/2tbsp fish sauce
1 tsp red curry paste
2 shallots, finely sliced
5 stems dill, coarsely chopped
10 lemon basil leaves
1 banana leaf

Method

  1. Soak the sticky rice in cold water for 30 minutes, then pound into a paste in a mortar, or in a food processor.
  2. Pound the garlic, chili, galangal, and lemongrass together in a mortar, then mix with the rice.
  3. Cut the salmon into fingers about 3-inch long without removing any skin, then gently mix them in a bowl with the pounded ingredients, adding the coconut milk, fish sauce, red curry paste and sugar.
  4. Stir in the shallots, dill and lemon basil, taking care not to break up the salmon fingers.
  5. Cut 4 oval shapes about 9-inch long and 6-inch wide and 4 rectangles about 4-1/2-inch by 3-inch from the banana leaf, plus a strip about 11-inch long 1/2-inch wide.
  6. Place the rectangles lengthways over the ovals to give two thicknesses of banana leaf in the centre. Place a quarter of the mixture in the centre of each of the rectangles. Make a parcel with the banana leaves and fasten it at the top with the banana leaf strip and a toothpick.
  7. Bring water to a fast boil in the bottom half of a steamer and steam the parcels for 12 minutes. Serve hot.

Makes 1 serving.

Source: The Blue Elephant Cookbook


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