Live attenuated vaccines

Definition

Live attenuated vaccines are a type of vaccine created from pathogens that have been weakened or attenuated so they can no longer cause disease in healthy individuals. These vaccines work by stimulating a strong immune response without causing illness, making them effective in preventing viral infections. They mimic natural infections closely, promoting long-lasting immunity and often requiring fewer doses compared to other vaccine types.

5 Must Know Facts For Your Next Test

1. Live attenuated vaccines can elicit both humoral and cell-mediated immunity, providing a comprehensive immune response.
2. Examples of live attenuated vaccines include those for measles, mumps, rubella (MMR), and yellow fever.
3. These vaccines often require careful storage conditions, such as refrigeration, to maintain their effectiveness.
4. While generally safe, live attenuated vaccines may not be suitable for immunocompromised individuals due to the risk of causing disease in these populations.
5. The use of live attenuated vaccines has significantly reduced the incidence of many viral infections worldwide.

Review Questions

• How do live attenuated vaccines compare to inactivated vaccines in terms of immune response?
  • Live attenuated vaccines typically generate a stronger and longer-lasting immune response compared to inactivated vaccines. This is because they closely mimic natural infections, allowing the immune system to mount a comprehensive response that includes both antibody production and cell-mediated immunity. In contrast, inactivated vaccines usually produce a more limited immune response, often requiring booster doses to maintain immunity.
• What precautions should be taken when administering live attenuated vaccines to vulnerable populations?
  • When administering live attenuated vaccines, it is crucial to screen for individuals who may be at risk, such as those who are immunocompromised or have certain medical conditions. Special considerations must be taken to avoid potential adverse effects, as these individuals may experience complications due to the weakened pathogens present in the vaccine. Health care providers should ensure proper timing and consult with specialists when necessary before vaccination.
• Evaluate the impact of live attenuated vaccines on public health and their role in achieving herd immunity.
  • Live attenuated vaccines play a critical role in public health by significantly reducing the incidence of infectious diseases and contributing to herd immunity. By vaccinating a large portion of the population, these vaccines lower the overall spread of pathogens, protecting those who cannot be vaccinated themselves, such as infants or individuals with certain health conditions. The successful implementation of live attenuated vaccination programs has led to the eradication or near-eradication of diseases like smallpox and polio in various regions, highlighting their importance in global health initiatives.

Related terms

Immunization: The process by which a person becomes protected against a disease through vaccination or natural infection.

Herd immunity: A form of indirect protection from infectious diseases that occurs when a significant portion of a population becomes immune, thereby reducing the overall spread of the pathogen.

Inactivated vaccines: Vaccines made from pathogens that have been killed or inactivated, which cannot cause disease but still stimulate an immune response.