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Scientists in Germany say they have been able to create a nasal vaccine that can stop COVID-19 infections in the nose and throat. The virus gets a chance to establish itself for the first time In the body.
In experiments on hamsters, two doses of the vaccine – which is made from a live but weakened form of the coronavirus that causes COVID-19 – stopped the virus from copying itself in the animals’ upper airways , thereby achieving “sterilizing immunity” and preventing disease. , a long-sought goal of the pandemic.
Although this vaccine must clear several more hurdles before it reaches a doctor’s office or drugstore, other nasal vaccines are in use or nearing the finish line in clinical trials.
China and India both rolled out vaccines delivered through nasal swabs last fall, though it is unclear how well they are working. Studies on the effectiveness of these vaccines have not yet been published, leaving much of the world to wonder whether this approach to protection actually works in people.
America has reached somewhat of a standstill due to COVID-19. Even after the darkest days of the pandemic have passed, hundreds of Americans are still dying every day as infections continue to simmer against the backdrop of our return to normal life.
As long as the virus continues to spread between people and animals, there will always be the possibility of it mutating into a more infectious or more harmful version. And while Covid infections have become manageable for most healthy people, they can still pose a threat to vulnerable groups such as the elderly and immunocompromised groups.
Researchers are hopeful that the next generation of COVID-19 vaccines, which aim to kill the virus before it has a chance to make us sick and ultimately stop the spread of infection, could make our latest resident respiratory infection less of a threat.
One way scientists are trying to do this is by boosting mucosal immunity, strengthening immune defenses in the tissues that line the upper airways, where the virus will land and begin to infect our cells.
It’s like deploying firefighters under the smoke alarm in your house, says study author Emanuel Wyler, a scientist at the Max Delbruck Center for Molecular Medicine at the Helmholtz Association in Berlin.
The immunity created by the shots works throughout the body, but it resides primarily in the blood. This means it may take longer to respond.
“If they’re already on the site, they can knock out the fire immediately, but if they’re 2 miles away, they need to drive there first, and by that time, a third of the house is already on fire.” It’s completely engulfed in flames,” Wyler said.
Mucosal vaccines are also better at provoking a different type of first response than injections. They do a better job of summoning IgA antibodies, which have four arms to grab invaders, rather than the two arms of Y-shaped IgG antibodies. Some scientists believe that IgA antibodies may be less selective about their targets than IgG antibodies, making them better equipped to deal with new variants.
The new nasal vaccine takes a new approach to a very old idea: weakening a virus so that it is no longer a threat and then giving it to people so their immune systems can learn to recognize and fight it. The first vaccines using this approach date back to the 1870s against anthrax and rabies. At the time, scientists weakened the agents they were using with heat and chemicals.
Researchers manipulated the genetic material in the virus to make it harder for cells to translate. This technique, called codon pair deoptimization, stops the virus so it can be presented 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 a different size, then it is very difficult to read the text. And that’s basically what we do in codon pair deoptimization,” Wyler said.
In the hamster study, which was published Monday in the journal nature microbiologyTwo doses of the live but attenuated nasal vaccine produced a stronger immune response than two doses of an mRNA-based vaccine or a dose that uses adenovirus to deliver vaccine instructions into cells.
Researchers believe the live attenuated vaccine probably works better because it more closely mimics the process of natural infection.
The nasal vaccine also previews the entire coronavirus to the body, not just its spike protein, as current COVID-19 vaccines do, so the hamsters were able to create immune weapons against a wide range of targets.
While all this sounds promising, vaccine experts say caution is necessary. The vaccine still needs to go through more trials before it is ready for use, but he says the results look encouraging.
“He did a great job. It’s clearly a capable and thoughtful team that did this work, and the scope of what they did is impressive. Now it just needs to be replicated, “probably in primates and certainly in humans, before it can be used widely,” said Dr. Greg Poland, who designed the vaccine at the Mayo Clinic. Was not involved in the research.
The study began in 2021, before the Omicron variant was around, so the vaccine tested in these experiments was made with the original strain of the coronavirus. In experiments, when they infected animals with Omicron, the live but weakened nasal vaccine still performed better than the others, but its ability to neutralize the virus was reduced. Researchers believe it will need an update.
It also needs to be tested in humans, and Wyler says they are working on it. Scientists have partnered with a Swiss company called RocketVax to begin Phase I clinical trials.
Other vaccines are in the pipeline, Poland said, but progress has been “slow and halting.” The groups working on these vaccines are struggling to raise the enormous costs of bringing a new vaccine to market, and they’re doing it in a setting where people think the vaccine race has been won and over. .
In fact, Poland said, we are far from that. All it would take is one more omicron-level change in the evolution of the virus, and we could be back to square one with no effective tools against the coronavirus.
“that’s silly. We must develop a pan-coronavirus vaccine that induces mucosal immunity and is long-lived,” he said.
At least four nasal vaccines for COVID-19 have reached late-stage trials in people, According too Vaccine Tracker of the World Health Organization.
Nasal vaccines in use in China and India rely on harmless adenoviruses to deliver their instructions to cells, although effectiveness data for these have not been published.
Two other nasal vaccines are completing human studies.
One, a recombinant vaccine that can be produced cheaply in chicken eggs, in the same way as many flu vaccines, is being put through its paces by researchers at Mount Sinai in New York City.
Another, like the German vaccine, uses a live but weakened version of the virus. It is being developed by a company called Codagenix. The results of those studies, which were conducted in South America and Africa, are expected later this year.
The German team says it is keeping a keen eye on the Codagenics data.
“They will be very important for knowing whether this kind of effort is fundamentally promising,” Wyler said.
They have reason to worry. Respiratory infections have proven difficult targets for inhaled vaccines.
FluMist, a live but weakened form of the flu virus, works quite well in children but does not help adults as much. This is thought to be because adults already have immune memory to flu, and when the virus is injected into the nose, the vaccine mostly boosts pre-existing immunity.
Nevertheless, some of the most powerful vaccines such as those against measles, mumps and rubella use live attenuated viruses, so this is a promising approach.
Another consideration is that live vaccines cannot be taken by everyone. People with very weak immunity are often cautioned against using live vaccines because even these very weak viruses can be risky for them.
“Although it has been significantly attenuated, it is still a real virus,” Wyler said, “so it has to be used with caution.”