Depth: The 3-year fight against the epidemic has entered the "endgame", China and India defeated the United States, and the new vaccine is more effective in cutting off the chain of virus transmission!

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(Source: "Time Magazine")
For those who had received the mRNA vaccine, it was a not so pleasant memory. The arm would be sore for several days, and some people even experienced fever, headache and muscle aches as side effects.Although injections of mRNA vaccines are effective in protecting people from severe illness or death,Its ability to prevent infection is poor,When the virus floods into the nasal cavity, it takes a while for the antibodies in the blood to reach the infection site, leaving an opportunity for the virus to invade.AndmThe protection of the vaccine decreases significantly after 4 months.
In order for humans to get rid of the new crown epidemic, it is necessary to find a way to stop the infection and spread of the virus. The inhaled or nasal spray vaccine came into being. This is a vaccine that works at the first line of defense when the virus enters the body. Compared with mRNA vaccines, nasal spray vaccines are more conducive to cutting off the chain of virus transmission.For example, mRNA is your bodyguard, your most important and last line of defense, andNasal sprayvaccineIt is the security guard patrolling around your home, the first line of defense against uninvited guests.
Why develop a nasal spray vaccine?
There's a reason scientists are working on a nasal spray vaccine that works through the mucous membranes of the nose, mouth and lungs. Covid is a respiratory virus that primarily attacks the cells in the airways, from the nose and throat all the way to the lungs.therefore,Vaccines that act directly on the tissues of the respiratory tract may stop the virus from infecting cells better than those injected into the arm, which typically need to spread throughout the body's circulatory system to be effective.
Dr. Akiko Iwasaki (Source: PNAS)
Dr. Akiko Iwasaki of Yale University said: "If you give the vaccine intranasally, you get a local immune response, which is fundamentally different from what you get with an intramuscular vaccine."The advantage of mucosal vaccination is that it can capture the virus before it enters our body.By limiting the amount of viral replication at points of contact, it also prevents infection and its potential consequences, including COVID-XNUMX sequelae.AsIf you can limit the virus from entering the body, it can also prevent further transmission of the virus to others."
Differences from Injectable Vaccines
Cells in the mucous membrane passages of the nose, mouth, and airways produced a different type of immune response than the type of immune response produced by vaccination in the muscles.The nasal spray vaccine produces an antibody called IgA that the injectable vaccine does not; vaccines injected into a muscle tend to produce more IgG antibodies.It's not that one antibody is better, but the two antibodies have different functions.IgA Antibodies are more localized-They are found in areas such as the respiratory tract, reproductive system, or gut.Produced in the mucous membrane layer in the part of the body where the virus is most likely to invade.IgG antibodies, on the other hand, are systemic and trigger antibodies to inactivate viruses circulating in the blood.When IgG antibodies are produced, they create systemic immunity, and if these viruses or bacteria break through the mucous layer to cause an infection, the body is better able to fight back, preventing severe illness and death.
Whether it is reducing the spread of viruses, increasing respiratory antibodies, or long-term immunity, nasal spray vaccines have their advantages. (Source: lovaltechnology)
animal study results
In a research paper published in June,National Institute of Allergy and Infectious Diseases (NIAID) The researchers found that intranasal inoculation COVID-19 Vaccines significantly reduce the amount of virus detected in the airways of animals."We couldn't find the virus in either the upper or lower respiratory tract, and we found that the intranasal vaccine prevented infection or eliminated it within two days," said Bernard Moss, a distinguished investigator at NIAID and the paper's senior author. )Say.The study also showed that people who had been infected with COVID-19 and recovered tended to have higher levels of IgA in their noses, making them less likely to be reinfected than people who were not infected.This further demonstrates the importance of IgA antibodies in protecting people from infection.
(Source: SCMP)
With the majority of the world's population now having some sort of immunity to COVID-XNUMX (whether acquired through vaccination or infection), Akiko Iwasaki believes it is time to use an inhaled vaccine instead of continuing to get mRNA boosters, which she describes as "Muscle and nasal" (injectable plus nasal spray) strategy.Her latest findings back up this strategy, with her team writing in the journal Science that,Inoculation m Mice that inhaled the nasal spray vaccine after the vaccine developed in the nose and mouth IgA Antibody levels higher than injection alone m vaccine or a dose of nasal spray vaccine.The "muscle and nasal" strategy also produced a robust immune response, including more immune T cells, which outlasted antibodies.however,Immunologist at Case Western Reserve UniversityStephenStephanie LangelMeans,althoughSome studies have shown that protection from nasal vaccines lasts for many months in animals, but there is no guarantee the same will be true in humans.
Lack of large-scale clinical human trials
The current study is limited to animals, and it's unclear whether the nasal spray vaccines will actually reduce infections in people until more people are vaccinated.Post-hoc analysis of whether people who received the nasal spray vaccine were able to fend off infection is the most feasible way to measure whether the vaccine is effective, only after a large number of vaccinations have been administered.It is impossible to answer the question of whether a vaccine works without testing the nasal vaccine on a large scale in humans in clinical trials.
(Picture source : SCMP）
This uncertainty has prevented the US government from investing in mucosal-based vaccines.About a dozen companies in the U.S. have completed or are close to completing initial animal studies of various nasal spray vaccines, but they lack the funding needed to test candidates through clinical trials on humans. “They had no financial support or risk protection, nothing. They were completely alone,” said Dr. Eric Topol, director of the Scripps Research Translational Institute.
US is being overtaken by China and India
The U.S. is losing ground when it comes to inhaled vaccine development. In September, India approved a nasal spray COVID-9 vaccine, and in October, China officially launched a nasal spray vaccine. Both countries are currently leaders in nasal spray vaccines.Both countries have conducted clinical safety and efficacy tests in humans (but complete and up-to-date results have not yet been published).
China is mass vaccinating its citizensNasal spray vaccine (Credit: Getty Images)
U.S. researchers have developed several nasal spray vaccines that have been tested in animals, and some of them look promising.But the rollout of the vaccine in the United States is at least a few years away, as critical human trials are stalled by a lack of funding.
Speed ​​up human testing
IncludeCoalition for Epidemic Preparedness Innovations (CEPI),Wellcome Trust (Wellcome Trust）和Bill & Melinda Gates Foundation (Bill and Melinda Gates Foundation convened a workshop in early November to expedite human testing of the nasal vaccine. CEPI is partnering with the National Institutes of Health to support more basic research on a mucosal COVID-11 vaccine, and in October announced a partnership with Dutch biopharmaceutical company Intravacc to develop a nasal spray vaccine. Forty volunteers are currently testing the company's first nasal spray vaccine, and those results are expected in early 19.
(Source: AP)
Akiko Iwasakiand her teamTwo other nasal vaccine strategies are being explored.One introduces a modified virus spike protein to wake up the immune system, while the other followsmtechnique, but inoculate by nasal spray. "It's a fundamentally different approach, and we need to test it," she said.The approach worked so well in animal studies that Iwasaki co-founded a company called Xanadu Bio to further test the vaccine and find industry partners to test it in humans.
The future may become the key to ending the epidemic
If successful,nasal sprayformulaVaccines can also help increase vaccination rates in resource-poor countries, where/Areas usually do not have the conditions for ultra-low temperature storage, which is not conducive to the vaccination of existing vaccines. Fewer side effects for kids or others who don't want to suffer from needles and the side effects of mRNANasal sprayVaccines are also easier to accept.even one day,Nasal sprayVaccines can be delivered by mail, and you can do it yourself at home.
(Source: SCMP)
Using a vaccine that significantly reduces the spread of the virus is the only way to reduce and ultimately stop the spread of the virus."We are in a constant war against the virus," CEPI chief executive Richard Hatchett said. "The use of an easy-to-administer intranasal vaccine will help reduce transmission and improve vaccine availability worldwide. It is too early to talk about eradicating COVID-19,But if we can't break the chain of transmission, we will never eradicate COVID-19."
参考资料
https://time.com/6226356/nasal-vaccine-covid-19-us-update/
https://www.theatlantic.com/health/archive/2022/12/covid-mucosal-vaccines-protection/672544/
https://www.scmp.com/magazines/post-magazine/long-reads/article/3180098/future-covid-19-vaccines-why-nasal-sprays-not
https://yaledailynews.com/blog/2022/11/10/new-yale-study-finds-promising-results-with-nasal-covid-19-vaccine/
https://www.science.org/doi/10.1126/sciimmunol.add9947
https://cen.acs.org/pharmaceuticals/vaccines/Intranasal-nose-vaccines-stop-COVID/99/i21

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