Attenuated virus

Attenuated virus refers to a virus that has been modified, or "attenuated", in a laboratory to weaken its virulence and reduce its ability to cause disease. This process is often used in the creation of vaccines, where the attenuated virus is used to stimulate an immune response without causing the full-blown disease.

History

The concept of using an attenuated virus for vaccination purposes dates back to the work of Louis Pasteur in the 19th century. Pasteur developed a method for attenuating the rabies virus by drying the spinal cords of infected rabbits. This weakened version of the virus was then used to create the first successful rabies vaccine.

Process of Attenuation

The process of attenuation involves reducing the virulence of a virus while maintaining its ability to induce an immune response. This is typically achieved through a process of serial passage, where the virus is grown in a series of cell cultures or host animals. With each passage, the virus adapts to the new host and loses its ability to cause disease in the original host organism.

Use in Vaccines

Attenuated viruses are used in many different types of vaccines, including those for measles, mumps, rubella, and polio. These vaccines are often referred to as live attenuated vaccines (LAVs). LAVs are highly effective because they elicit a strong and long-lasting immune response, similar to that produced by a natural infection.

Risks and Limitations

While attenuated virus vaccines are generally safe and effective, they are not without risks. In rare cases, the attenuated virus can revert to its virulent form and cause disease. This is a particular concern for individuals with weakened immune systems, who may not be able to fight off the infection. Additionally, attenuated virus vaccines often require careful storage and handling to maintain their effectiveness, which can pose challenges in resource-limited settings.

See Also

• Vaccine
• Virus
• Immunology
• Public Health