Recently, CanSino Bio (688185.SH, 06185.HK) and the Institute of Biological Engineering of the Academy of Military Sciences jointly developed a recombinant new coronavirus vaccine for inhalation (adenovirus type 5 Ad5-nCoV) that was approved by the National Medical Products Administration. Test approval. The previous 14-day prevention success rate of this vaccine was 68%, while the success rate of preventing serious diseases was as high as 95%, showing good effectiveness.
This nasal spray formulation can quickly achieve immune protection, shorten the vaccination cycle, and achieve herd immunity in the shortest time, and the virus can be stored between 2 to 8 degrees, which is particularly convenient for nasal spray preparations. The market gave a very enthusiastic response. However, looking at it recently, its stock price rose first and then fell, and the capital market raised questions about the formulation of the new nasal spray. So, there are various new dosage forms of the new crown vaccine, which one will usher in the spring of success in the end? This article does an analysis.
Figure 1 The recent market quotations of Cansino shares, first rose and then fell
Is subcutaneous injection the only way to vaccinate?
Under normal circumstances, many of us imagine that getting immunized is like getting a flu vaccine: we will go straight to hospitals at all levels, roll up our sleeves, feel a rapid tingling in our arms, and the new vaccination will be done. This is what is happening in the current vaccination. Most of the current vaccination is directly injected into the arm because the arm muscle has a certain dose slow-release effect, which can slowly release the effective ingredients of the vaccine so that the human body has time to respond. Then slowly the body's immune system produces antibodies against the virus.
However, everyone knows that the new coronavirus is transmitted through the respiratory tract. Therefore, can a corresponding nasal spray vaccine for the respiratory tract be developed? This vaccine will be delivered as a nasal spray directly to the human respiratory tract, where the SARS-CoV-2 virus may invade and reproduce (the lungs and upper respiratory tract, etc.) directly stimulate an immune response. A paper published in Science showed that the new nasal lipopeptide may be an ideal choice to prevent the global spread of the new coronavirus. This method of administration is stable in transportation, convenient to use, and can be widely used.
Figure 2 Science reports that nasal medication can combat the new coronavirus
In addition to the nasal cavity of the vaccine, oral mucosal administration is also a new way
In theory, this site-specific strategy may provide stronger protection against COVID-19 coronavirus disease than vaccination, because it is closer to natural COVID-19 infection and is at the key position where the virus enters. Produce antibodies and immune cells.
Also, vaccine components that use bacteria as carriers can deliver antigens directly to the mucosal tissues of the nose and oral cavity. The antigen is a vaccine component that can trigger an immune response. Mucosal vaccines should be effective because mucosal vaccines can induce immunity when the virus enters and control early infections before it becomes a definite systemic infection. Utilize some unique and powerful components in the mucosal tissues of the human immune system. The b cells in the mucosa produce immunoglobulin A and interferon, which are the body's strong first-line defense against intestinal and respiratory pathogens. Mucosal tissue is also rich in memory. T cell cells can "remember" specific antigens after they cross the mucosal tissue for the first time so that they can produce a faster and stronger immune response the next time they cross.
The new crown vaccine is administered through the mucous membrane, which has obvious advantages
If the new crown vaccine uses mucosal administration, it must use viruses or bacteria as carriers. For example, the nasal spray preparation studied by Cansino is the adenovirus vector used. This carrier is generally active. The use of active viral or bacterial vectors has at least 4 advantages. First of all, as a live virus or active bacteria that can be used in the human body, it is generally safe and acceptable to the human body. Secondly, it can also be transplanted to mucosal sheets, which means that it lives and reproduces harmoniously with other bacteria in the airway. This situation will cause the protective effect of the new vaccine to last longer and reduce the number of times individuals need to be vaccinated. In the end, you may only need to spray the nose once and it will be effective for 3 months. Thirdly, thanks to the modern genetic engineering production process, the production cost of bacteria or live viruses is relatively low, and it is very feasible to produce SARS-CoV-2 antigen through genetic engineering of bacteria. Finally, compared with other vaccines, the equipment cost of mucosal vaccines is low. On the one hand, it can skip the expensive and difficult antigen purification process. On the other hand, spraying does not require needles and does not require well-trained medical staff, which greatly saves money. Human and social resources.
summary
In short, due to the widespread of the global new crown virus, we can know that the new crown vaccine will not be the only one in the future, but will be in a state of contention. Because the products of a single manufacturer cannot cover the world, only the combined vaccines (nasal mucosa, intramuscular injection, intravenous injection, etc.) can be used to ensure global coverage. At present, the pandemic of the new crown epidemic is not expected to subside in a short period of time. At the same time, as the new crown virus continues to mutate, people in different countries also need different vaccines, which are constantly replaced and cross-immunized.
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