CHARACTERIZATION OF MEASLES VIRUSES ISOLATED AFTER MEASLES VACCINATION

Seven measles virus (MV) strains were isolated from children who devel oped clinical signs of fever and rash 3-9 days after measles vaccinati on. The nucleotide sequence of the H gene, the molecular size of the H protein, the haemadsorption activity on African green monkey red bloo d cells, and antigenicity as determined by virus neutralization reveal ed that one strain was of the vaccine type and the remaining six were the wild virus type, Isolation of the virus directly from patients sus pected of a vaccine-induced side-reaction and subsequent characterizat ion of such isolated virus may be useful in differentiation between va ccine-induced side-reactions and natural measles.