Worldwide, the cumulative number of new crown diagnosis has exceeded 20 million, and the number of deaths has exceeded 750000. In many countries and regions, people are looking forward to the new crown vaccine can be launched as soon as possible, so that people have immunity to the virus. However, the protective effects of different vaccines are different. Some vaccines only need to be injected once for life, while others can only provide temporary protection after injection. The influenza vaccine, as we know it, belongs to the latter. In some extreme cases, vaccines vaccinated in early autumn fail before late winter. Today, a paper published online in science, a leading academic journal, explains why the protective effect of many influenza vaccines is not long-lasting. < / P > < p > this study is from the research group of Professor Rafi Ahmed of Emory University. As early as 1996, he helped discover a kind of B cell in bone marrow, bone marrow plasma cell (bmpc). In the event of an infection or vaccination, the cells produce antibodies in an endless stream. In some cases, these cells survive for years, providing long-term protection. However, it is not known whether the influenza vaccine can stimulate the production of these cells, and whether these cells can form long-term protection against influenza. To answer this question, the researchers designed an experiment in which 53 volunteers aged 20-45 were recruited. In the experiment, the volunteers provided scientists with bone marrow and blood samples for weeks or months before and after the flu vaccine. From this, scientists can find the plasma cells that appear only after influenza vaccination. The virus was found in the blood plasma of the influenza vaccine < 4 weeks after inoculation. After a year, however, the new cells disappeared. Correspondingly, although the newly produced antibodies began to increase one month after inoculation, they also began to decrease after one year. On the contrary, those antibodies not brought by the vaccine remained relatively stable over the course of a year. < / P > < p > based on these findings, researchers have figured out why influenza vaccines don’t last long – it’s not enough to have plasma cells that produce antibodies. If they can’t find a place to “settle” in their bone marrow, they won’t last long. Of course, this discovery also leads us to the direction of optimizing the vaccine. For example, there is no adjuvant to enhance the immune response in the current influenza vaccine. The researchers point out that if we add adjuvants to the vaccine in the future, we may be able to extend the effectiveness of the vaccine. < / P > < p > considering that we do not know how long the protective power of the new coronal vaccine is, perhaps this study can give scientists enlightenment to better understand the protection potential of the new crown vaccine, so as to better deal with the global epidemic situation.