Language
Country/Area
No result found
The immune system's best friend: Why do live, attenuated vaccines provide ultra-long-lasting protection?
Vaccine development plays a pivotal role in today's public health advancements. Live Attenuated Vaccines (LAV), in particular, have shown great potential in providing long-term immune protection. These vaccines attenuate the pathogens so that they are no longer pathogenic, but they can still activate the body's immune system and promote the production of antibodies and immune memory cells to protect the body from infection.
Live attenuated vaccines can more effectively simulate natural infections and stimulate the body's strong immune response to specific pathogens.
The development process of live attenuated vaccines
The production of live attenuated vaccines mainly depends on the transmission process of pathogens. This process usually occurs by transmitting viruses or bacteria into foreign hosts such as eggs, animals, or tissue cultures. For example, when viruses reproduce repeatedly through foreign hosts, they gradually adapt to the new host environment, thereby reducing their pathogenicity in the original host. This process is also called "propagation".
When a virus successfully adapts to a new host, it will no longer cause harm to the original host, allowing the immune system to more effectively eliminate pathogens and build immune memory.
Mechanism of live attenuated vaccines
The working principle of this type of vaccine is based on activating the body's two immune responses: cellular immunity and humoral immunity. Live attenuated vaccines promote the production of CD8+ and CD4+ T lymphocytes and antibodies, cells and molecules that help prevent or reduce infection. In contrast, inactivated vaccines are generally less effective than live, attenuated vaccines.
B cell activation can be T-cell dependent or independent, both of which can effectively strengthen the immune response.
Safety and side effects
Most live attenuated vaccines are considered relatively safe, but in some cases, certain groups of people, such as people with severely compromised immune systems or pregnant women, may be at higher risk. Although live attenuated vaccines provide long-lasting immune protection, they may still cause potential health problems when the immune system fails to respond appropriately.
According to WHO data, serious adverse reactions to live attenuated vaccines are very rare, but attention still needs to be paid to certain high-risk groups.
The history and evolution of live attenuated vaccines
The history of vaccines begins in the 18th century, when Edward Jenner invented the cowpox vaccine to combat smallpox. Subsequently, scientists such as Louis Pasteur carried out further expansion and developed a variety of live attenuated vaccines, such as measles, mumps, rubella, etc. These historical milestones have laid a solid foundation for modern vaccine research and development.
Advantages and disadvantages of live attenuated vaccines
Advantages
- Effectively simulates natural infection and stimulates a strong immune response.
- Can achieve long-term or lifelong immunity.
- Usually only one or two doses are needed.
- The cost is relatively low and it has a rapid immune effect.
Disadvantages
- In some rare cases, a live attenuated virus may evolve back into its pathogenic form.
- Use is generally not recommended for pregnant women and those with extremely compromised immune systems.
- It needs to be kept in a specific environment to ensure the activity of the vaccine, and the transportation cost is relatively high.
Summary
Live attenuated vaccines are undoubtedly in a unique position among vaccine types in that they not only effectively simulate the infection process but also stimulate long-term defensive stress on the immune system. However, how to manage the use of live attenuated vaccines while maintaining public health still requires further exploration and thinking?
