<unk>  (VISP) is the phenomenon wherein a person who has received a vaccine against a disease would thereafter give a positive or reactive test result for having that disease when tested for it, despite not actually having the disease. This happens because many vaccines encourage the body to produce antibodies against a particular disease, and blood tests often determine whether a person has those antibodies, regardless of whether they came from the infection or just a vaccination. VISP is especially a concern in vaccine trials for HIV vaccine research because people who give a positive result in an HIV test, even if that result is because of a vaccine and not because of an infection, may face discrimination because of HIV infection.
Vaccine-induced seropositivity
Subclinical infection
Immunization during pregnancy
Latent iron deficiency
Vaccine-associated enhanced respiratory disease
Vaccine resistance
Non-specific effect of vaccines
Intentional contagion of infection