atypical measles

a·typ·i·cal mea·sles

sometimes severe, unusual clinical manifestation of natural measles virus infection in people with waning vaccination immunity, particularly in those who had received formaldehyde-inactivated vaccine; an accelerated allergic reaction apparently resulting from an anamnestic antibody response, characterized by high fever, absence of Koplik spots, a shortened prodromal period, atypical rash, and pneumonia.

atypical measles

A serious illness that occurred in children immunised with an inactivated vaccine against measles virus in the 1960s, which failed to elicit long-lived protective antibody and a cytotoxic T-lymphocyte response.

Clinical findings
High fever, headache, cough, abdominal pain, followed by rash 1 to 2 days later, often beginning on the limbs, acral oedema; pneumonia is common and may persist for 3 months or more.

Pathogenesis
Post-vaccination exposure to wild-type virus during community outbreaks was associated with immune complex deposition in affected tissues, brisk CD4+ T lymphocyte proliferative responses, and a Th2 bias of the immune response.

a·typ·i·cal mea·sles

(ā-tip'i-kăl mē'zĕlz)

Unusual clinical manifestation of natural measles infection in people with waning vaccination immunity, particularly in those who had received formaldehyde-inactivated vaccine; an accelerated allergic reaction characterized by high fever, absence of Koplik spots, a shortened prodromal period, atypical rash, and pneumonia.