Comparison of Severity of Viremia and Antibody Responses between Infants and Children with Measles

Severity of viremia and neutralizing antibody responses were compared between nine young infants ( 10 months) with measles and 18 infants and children ( 11 months) with ordinary measles. Peripheral blood mononuclear cell (PBMC)‐associated viremia was detected between the first day of elevation of fever (day 0) and day 5 of the disease in the former group, whereas PBMC‐associated and cell‐free viremia were detected between day 0 and day 14 in the latter group. The number of infected PBMC during the first 7 days of the disease was 3.22 ± 1.07 (log₁₀, mean ± s.d.) per 10 million PBMC in the former group, which was significantly smaller (P= 0.02) than that of the latter group (4.21 ± 1.18). The former group reached the maximum level of antibody earlier than the latter group.