What type of vaccine requires a booster for long-term immunity?

Inactivated vaccines are designed from pathogens that have been killed or inactivated so that they can no longer cause disease. Because these vaccines do not replicate in the host, they tend to produce a weaker immune response compared to live-attenuated vaccines. As a result, they usually do not provide long-lasting immunity and often require booster doses to maintain sufficient protective antibody levels.

For example, inactivated vaccines are commonly used for diseases such as rabies and certain strains of influenza. The immune system is less stimulated by these vaccines, and over time, the effectiveness wanes, necessitating that boosters be administered at specified intervals to ensure continued immunity.

In contrast, live-attenuated vaccines replicate in the host and usually elicit a stronger, longer-lasting immune response, often leading to lifelong immunity after just one or two doses. Recombinant vaccines utilize pieces of the pathogen to stimulate immunity without the risks associated with live pathogens. mRNA vaccines are designed to instruct cells to produce a protein that triggers an immune response, and they have shown the ability to confer strong immunity as well, often not requiring as frequent boosters as inactivated vaccines.