RT Journal A1 PREBLUD SR, NIEBURG PI, BRANDLING-BENNETT A, HINMAN AR, HERRMANN KL T1 RUbella vaccination JF American Journal of Diseases of Children JO American Journal of Diseases of Children YR 1979 FD November 1 VO 133 IS 11 SP 1202 OP 1202 DO 10.1001/archpedi.1979.02130110110026 UL http://dx.doi.org/10.1001/archpedi.1979.02130110110026 AB Sir.—We wish to comment on the recent article in the Journal by Balfour and Amren (132:573-577, 1978) and the subsequent commentary by Dudgeon (132:748-750, 1978) regarding rubella vaccine-induced immunity. The rubella geometric mean titers (GMTs) of seropositive persons reported by Balfour and Amren are lower than those usually seen in vaccine recipients.1.2 This fact plus the unusually high rate of seronegativity, which they acknowledge, suggest that the antibody assay system they used was relatively insensitive. Were the results obtained when the sera were sent to Cincinnati similar to those obtained locally in incidence of seronegativity and in GMT?We agree with Balfour and Amren that "the critical issue is whether the seronegative girls are truly susceptible to rubella." We do not believe, however, that "the only way" to find out is to challenge them with wild rubella virus. Instead, we agree with the suggestion made previously by these