▎ WuXi AppTec content team editor
new coronavirus infection usually starts in the nasal cavity or pharynx. The infection has taken root in the nasal cavity or pharynx before the systemic immunity begins. Therefore, a nasal spray vaccine that can produce both systemic immunity and local immunity has better preventive effects.
The main goal of the
COVID-19 vaccine is to protect vaccinated persons from serious illness and death from infection with the new coronavirus. But the more important goal is to prevent the spread of disease. Although it is not yet clear, most vaccine candidates under development can do this. Some scientists believe that this problem can be solved by vaccination through nasal spray.
▲ Dr. Frances Lund, Dean of the Department of Microbiology, University of Alabama at Birmingham School of Medicine (Image source: University of Alabama at Birmingham official website)
University of Alabama at Birmingham School of Medicine Charles H. McCauley Chair Professor and Director of the Department of Microbiology, Dr. Frances Lund, said that most vaccines, including all vaccines currently undergoing clinical trials, are administered by intramuscular injection. The intramuscular injection site is usually the upper arm deltoid . Intramuscular vaccination often produces a strong immune response. Therefore, most vaccine development agencies focus on intramuscular vaccines. Although intramuscular vaccination can produce a systemic immune response through the blood circulatory system, it cannot produce a local response.
For respiratory viruses such as the new coronavirus, the infection usually starts in the nasal cavity or pharynx, and the infection has taken root in the nasal cavity or pharynx before the systemic immunity begins. Intramuscular injection of the vaccine can protect the vaccinated from serious diseases, but the vaccinated may still carry the virus in the nasal cavity and spread it to others. The nasal spray vaccine can provide another kind of immunity, which mainly exists in the cells of the nasal cavity and pharynx. If inoculated through the nasal cavity, in addition to obtaining systemic immunity, it also increases a local immunity, which cannot be achieved with intramuscular vaccines. Systemic immunity can prevent vaccinators from getting sick, while local immunity means that it will be more difficult for the virus to start infection in the nasal cavity-the virus in the "infected bag" in the nasal cavity can easily be spread to others through breathing or sneezing. Dr. Lund is working with Altimmune to develop such a vaccine.
If the new vaccine is completely effective and everyone is vaccinated, there is no need to worry about vaccinated people exhaling the virus to infect others, but this situation is difficult to achieve. Dr. Michael S. Diamond, Herbert S. Gasser Chair Professor of Medicine, Molecular Microbiology, Pathology, and Immunology at the University of Washington, said that with the exception of those who have not been vaccinated, some people will not have enough vaccine responses, which means these The human body does not produce antibodies that protect the vaccinated person.
▲ Dr. Michael S. Diamond, Herbert S. Gasser Chair Professor of Medicine, Molecular Microbiology, Pathology and Immunology, University of Washington (Image source: University of Washington official website)
: Reference [1]
Diamond said that although nasal spray vaccines are not common at present, there are vaccines for other diseases, such as the Fl currently in use.umist flu vaccine. Dr. Diamond hopes to use the existing nasal spray technology.
is similar to this strategy. On August 21, the journal Nature Communications published a report from Dr. Ling Chen from the State Key Laboratory of Respiratory Diseases, Dr. Zhiming Yuan from the Wuhan Institute of Virology, Chinese Academy of Sciences, and Guangzhou En A signed paper by Dr. Guan Suhua of Baosteel Biosciences reported an adenovirus vaccine (Ad5-S-nb2) that carries a gene sequence encoding a spike protein, and the sequence has been codon optimized. Intramuscular injection of Ad5-S-nb2 in mice and rhesus monkeys can cause systemic spike protein-specific antibodies and cell-mediated immunity (CMI) responses. Intranasal vaccination can cause systemic and lung antibody responses, but the CMI response is weak. After 30 days of intramuscular injection or nasal spray inoculation of rhesus monkeys with Ad5-S-nb2 vaccine, it has a protective effect against SARS-CoV-2 challenge.
We expect that a nasal spray COVID-19 vaccine that can produce both systemic immunity and local immunity and better preventive effects will come out soon.
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Reference:
[1] Ahmed O. Hassan, Natasha M. Kafai1, Igor P. Dmitriev, et al. A single-dose intranasal ChAd vaccine protects upper and lower respiratory tracts against SARS-CoV-2. Cell, August 19 , 2020 DOI: https://doi.org/10.1016/j.cell.2020.08.026
[2] Joe Palca. What A Nasal Spray Vaccine Against COVID-19 Might Do Even Better Than A Shot. Aug 28, 2020. Retrieved Aug 29, 2020 from https://health.wusf.usf.edu/post/what-nasal-spray-vaccine-against-covid-19-might-do-even-better-shotstream/0
[3] Liqiang Feng, Qian Wang, Chao Shan, et al. An adenovirus-vectored COVID-19 vaccine confers protection from SARS-COV-2 challenge in rhesus macaques. Nat Commun. 2020 Aug 21;11(1):4207. doi: 10.1038/s41467- 020-18077-5
[4] WuXi AppTec's content team. "Nature" magazine: A spray in the nose is expected to produce protection? The new coronavirus vaccine demonstrates positive results. Aug 22, 2020. Retrieved Aug 22, 2020 from https://tech.sina.com.cn/d/i/2020-08-22/doc-iivhvpwy2301519.shtml
Note: This article aims to introduce the progress of medical and health research, not to recommend treatment options. If you need guidance on treatment plans, please go to a regular hospital for treatment.
