[Suburban Gal]

The evidence is strong that immunity persists for years or for life from vaccines early in life, and the risk of chronic illness is significantly increased with vaccine repetition. So, if someone runs a titer test in place of vaccinating Spot, and Spot’s titer is low, perhaps 6-8 years after his last vaccine, the recommendation is likely to be “Spot needs another round of vaccines to keep him safe.” I’d like to show that this is a wrong line of thinking that will get a lot of animals unnecessarily vaccinated, and therefore, at greater risk for developing chronic disease.

Titer testing only measures one fraction of the entire immune response, the antibodies produced against a particular organism. While their presence indicates protection, there’s no reason for the immune system to keep producing antibodies against an invader forever, so, over time, these levels of antibody will wane. The fight is finished, there’s no more invader showing up, so there’s no need to keep a titer high.

What isn’t measured by the titer test is any part of the cell-mediated immunity, especially the memory cells. So, while antibody levels will wane over time, these long-lived memory cells lie quietly in the recesses of the immune system, awaiting further signals that the invader is back. It’s these cells that are responsible for the duration of immunity that can’t be measured by a titer test.

That said, I think titering is a mistake.

• This reply was modified 10 years, 6 months ago by Suburban Gal.