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Infection testing after vaccination


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This is my first post, and I am no doctor, so please go easy on me

 

What I would like to know know is information on the following scenario :

 

A healthy indivdual is vaccinated. One week afterwards, the individual is tested for the virus (not antibodies) the individual has been vaccined for . Are the test results going to be positive effect or negative for infection?

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If the test only consists of the quantification of the antigen(s) on which the vaccine is based there is a certain chance of positive detection. Most data has been obtained on the Hepatitis B surface antigen, which is used as vaccine as well as for diagnostic purposes. As a rule of thumb the levels drop continuously, until it reaches the (diagnostic) detection limit of standard tests (about two weeks). The rate appears to to vary considerably between individuals and it should be noted that most data has been obtained from hemodialysis patients that are continuously monitored. So it may not perfectly reflect the average population.

 

Many tests use several parameters, which reduces the risk of false positives to some extent (in case of hepatitis the core antibody is normally also tested, for example).

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thx for your answer. to be honest, my question is applied to dogs in my case, but I'm curious for human cases as well.

 

So the answer is, without several parameters, there is a considerable chance of a false positive.

 

the original Scenario was puppies being vaccined, turning up sick a week after vaccination (there is a grace time of 1 week not to expose them to stress after vaccination), then being tested for common viruses (by a third party) which then turn out positive. I do not know exaclty how extensive viral testing is for puppies, I do know there are 2 kinds, a simple swap test with a positive/negative indicator (sort of like a pregnancy test), and a blood test where abnormal values suggest viral infection.

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