Cnn
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Germany scientists say they have been able to make a nasal vaccine that can stop a covid-19 infection in the nose and throat, where the virus obtains its first foot in the body.
In experiments in hamsters, two doses of the vaccine – which is made with a living but weakened form of the coronavirus which causes a covid -19 – prevented the virus from copying in the upper airways of animals, of reaching “sterilized immunity” and of preventing the disease, a long objective of the pandemic.
Although this vaccine has several additional obstacles to erase before it reaches a doctor’s office or a pharmacy, other nasal vaccines are used or approach the clinical trials finish line.
China and India both deployed vaccines given through nasal tissues last fall, although it is not clear how they can work. Studies on the effectiveness of these vaccines have not yet been published, leaving a large part of the world to wonder if this approach to protection really works in people.
The United States has reached a dead end with COVID-19. Even with the darkest days of the pandemic behind us, hundreds of Americans always die daily while the infection continues to simmer in the background of our return to normal life.
As long as the virus continues to spread among people and animals, there is always the potential to mutate into a more contagious or more damaging version of itself. And while infections have been managed to manage most healthy people, they can still constitute a danger for vulnerable groups such as the elderly and immunocompromised.
Researchers hope that new generation COVI-19 vaccines, which aim to close the virus before you have the opportunity to get sick and prevent the spread of infection, could make our new respiratory infection residents less a threat.
One way that scientists try to do so is to stimulate mucous immunity, strengthen immune defenses in tissues that line the upper respiratory tract, where the virus would land and begin to infect our cells.
It’s a bit like parking the firefighters under the back of the smoke in your house, explains the author of the study Emanuel Wyler, scientist of the Max Delbruck Center for Molecular Medicine of the Helmholtz association in Berlin.
Immunity created by shots works throughout the body, but it resides mainly in the blood. This means that it can take longer to put an answer.
“If they are already there, they can immediately eliminate the fire, but if they are 2 km away, they must first drive, and at that time, a third of the house is already in flames,” said Wyler.
Mucous vaccines are also better to start another type of first answering machine from that of injections. They do a better job to invoke IGA antibodies, which have four arms to grasp on the invaders instead of the two arms that the IgG antibodies in the shape of there. Some scientists believe that IGA antibodies can be less picky on their targets than IGG antibodies, which makes them better equipped to cope with new variants.
The new nasal vaccine adopts a new approach to a very old idea: weakening a virus so that it is no longer a threat and give it to people so that their immune systems can learn to recognize and fight it. The first vaccines using this approach date from the 1870s, against anthrax and rage. At the time, scientists weakened the agents they used with heat and chemicals.
Researchers have manipulated genetic material in the virus to make it more difficult to translate it from cells. This technique, called the decline of codon pairs, hinders the virus so that it can be shown to the immune system without making the body sick.
“You can imagine reading a text … And each letter is a different font, or each letter is of a different size, then the text is much more difficult to read. And this is essentially what we do in the boosting of the pairs of codons,” said Wyler.
In Hamster studies, which were published on Monday in the journal Nature Microbiology, two doses of the living but weakened nasal vaccine created a much stronger immune response than two doses of an mRNA or one which uses an adenovirus to transport the instructions of the vaccine in cells.
Researchers think that the weakened vaccine lives probably worked better because it closely imitates the process of a natural infection.
The nasal vaccine also previews the entire coronavirus for the body, not only its points of spikes such as current COVVI-19 vaccines, so that hamsters have been able to make immune weapons against a larger range of targets.
As promising as it may seem, vaccine experts say prudence is justified. This vaccine must still pass more tests before it is ready to use, but they say that the results seem encouraging.
“They did a very good job. It is obviously a competent and thoughtful team that has done this work, and impressive in the scope of what they have done. Now, you just have to be repeated”, perhaps in the primates and certainly in humans before it could be widely used, said Dr Greg Poland, who designs vaccines at Mayo Clinic. He was not involved in the new research.
The study began in 2021, before the Omicron variant was around, so that the vaccine tested in these experiments was carried out with the original strain of the coronavirus. In experiences, when they infected animals by omicron, the living but weakened nasal vaccine has always performed better than the others, but its ability to neutralize the virus has been reduced. Researchers think he will need an update.
He must also be tested in humans, and Wyler says they work there. Scientists have teamed up with a Swiss company called Rocketvax to start phase I clinical trials.
Other vaccines are more distant, but progress has been “slow and interrupted,” said Poland. The groups working on these vaccines find it difficult to increase the high costs of placing a new vaccine on the market, and they do it in a setting where people tend to think that the vaccine race has been won and done.
In reality, Poland said, we are far from that. All you need is another omicron level change in the evolution of the virus, and we could be back to square one, without effective tools against the coronavirus.
“It’s stupid. We should develop a pan-coronavirus vaccine which induces mucous immunity and which has a long time,” he said.
At least four nasal vaccines for COVID-19 have reached advanced stage tests in people, according to the World Health Organization Vaccine Tracker.
The nasal vaccines used in China and India are based on harmless adenoviruses to transport their instructions in cells, although efficiency data for them have not been published.
Two other nasal vaccines finish human studies.
One, a recombinant vaccine that can be produced at a lower cost in chicken eggs, in the same way as numerous flu vaccines, is put to the test by researchers from Mount Sinai in New York.
Another, like the German vaccine, uses a living but weakened version of the virus. It is developed by a company called Codagenix. The results of these studies, which were conducted in South America and Africa, could arrive later this year.
The German team says that he looks impatiently to Codagenix data.
“They will be very important to find out whether this type of attempt is fundamentally promising or not,” said Wyler.
They have reasons to worry. Respiratory infections have turned out to be difficult targets for inhaled vaccines.
Flurist, a living but weakened form of the flu virus, works fairly well in children but does not help adults so much. It is believed that the reason is that adults already have an immune memory for flu, and when the virus is injected into the nose, the vaccine mainly stimulates what is already there.
However, some of the most powerful vaccines such as the measles vaccine, mumps and rubella use alive attenuated viruses, so it is a promising approach.
Another consideration is that live vaccines cannot be taken by everyone. People with very compromised immunity are often warned against the use of living vaccines because even these very weakened viruses can be risky for them.
“Although it is strongly attenuated, it is always a real virus,” said Wyler, so it would be necessary to be used with care.
