StemCell Therapy

The largest army of immune cells in the body work together to filter out all the pathogens we inhale every day, defeating viruses and other invaders without us ever knowing.

But viruses have evolved tricks of their own, allowing them to infect the cells and use its molecular machinery to copy itself over and over before spreading down into the lungs and the rest of the body.

Current generation COVID-19 vaccines offer fantastic protection against serious illness and death by recruiting antibodies in the blood that can block the virus spreading to the organs. But these vaccines struggle to generate antibodies in the nose.

The big issue is infection. The current gen of vaccines dont stop infection, said Associate Professor Nathan Bartlett, head of viral immunology at Hunter Medical Research Institute and the University of Newcastle. The virus can continue to circulate, attacking the vulnerable and finding new ways to mutate around our defences.

At least eight nasal vaccines for COVID-19 are in development, according to the World Health Organisation.

They include a phase 1 trial of Tetherexs nasal COVID-19 vaccine SC-Ad6-1 led by the University of Queenslands Associate Professor Paul Griffin. The spray contains a harmless virus modified to look like SARS-CoV-2. The virus infects nose cells and replicates theoretically prompting the immune system into a strong response.

People wear face masks in Melbourne in July.Credit:Getty

Bartlett is working with ENA Respiratory to develop INNA-051, a nose spray full of molecules that bind to cell receptors that trigger the bodys powerful innate immune system, which is capable of fighting off viruses without needing antibodies or T cells. It gives the immune system a head start, Bartlett said.

However, that head start lasts only a week. Bartlett expects the spray would need to be used every week to maintain protection.

In animal trials, the treatment dramatically reduced COVID-19s ability to replicate in the nose. The treatment Bartlett is careful not to call it a vaccine is now in phase 2 clinical trials in humans.

Nasal vaccines face a key challenge: getting a strong and long-lasting immune response in the nose.

The nose is constantly exposed to viruses, bacteria and pollution, so every time we breathe in, immune cells there are much less aggressive than in other parts of the body.

All the stuff were breathing in, if we responded aggressively, wed have a lot more allergies, Griffin said. And antibodies generated in the nose are typically short-lived.

Another problem is getting the dose right. This is easy with a syringe into a vein, but very difficult when spraying fluid into the nose. What if the users nose is blocked? What if they sneeze? The vaccines also need to be carefully designed to not cause an allergic reaction.

And then there is the mucus itself. Vaccines need to penetrate it to get an immune response and then must stay around long enough to really fire up the system a tough task when mucus is constantly being cleaned out of the nose.

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Griffin said he was confident well get at least one intranasal protection soon. Bartlett is less so. He points out that regulators are unlikely to offer quick emergency approval to new vaccines now and any vaccine that gets approved would likely be out of date immediately, as the virus continues to mutate.

Whether it will have a huge impact on this pandemic, Im not sure, he said. But its critical for protecting us against the next one.

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Nasal vaccines could snuff out COVID, but the hurdles are not to be sneezed at - Sydney Morning Herald

This entry was posted on August 19, 2022 at 2:08 am and is filed under Immune System. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed. |