Circulating Interferon after Measles Vaccination

LIVE measles vaccine1 given without gamma globulin protects children from the clinical manifestations of natural measles even if given as late as three days after exposure.2 3 4 Krugman et al.5 have suggested that this early protective effect may be an example of viral interference in man. This inhibition of viral replication due to a prior viral infection may be mediated by interferon, an antiviral protein made by animal cells in response to a viral infection. Interferon has been found in the pharyngeal washings of patients with influenza,6 in the spinal fluid of certain patients with viral meningitis7 and occasionally in the . . .