Persistence of rubella antibody 8-18 years after vaccination.

1043 have been due to direct trauma or haematoma around an aberrantly coursing hypoglossal nerve, we still consider high puncture of the internal jugular vein to be a useful approach. Immunity induced by rubella vaccines must persist throughout the childbearing years, a period of about 30 years. We have reported persistence of rubella antibody at values exceeding 15 000 IU/l in 89 4% of volunteers vaccinated six to 16 years earlier.' We now present the results of retesting these vaccinees two years later. Methods and results Serum samples were obtained between March and June 1983 from 93 of the 123 vaccinees previously tested.' Sixty three volunteers had been vaccinated with RA27/3, HPV77-DE5, Cendehill, or a Japanese vaccine To-336 eight to 10 years previously while student nurses at St Thomas's Hospital, London. Thirty volunteers had been vaccinated with either RA27/3 or Cendehill vaccine 13-18 years previously while student nurses at The Hospital for Sick Children, London. Eight of these 93 vaccinees had low antibody values (< 15 000 IU/1) when tested in 1981 and were subsequently revaccinated with RA27/3 by the intranasal route.2 Sera were tested for rubella antibodies by single radial haemolysis3 and for rubella specific IgG by radioimmunoassay.4 Sera were compared with the standard serum containing 15 000 IU rubella antibody per 1, which is accepted as indicating a satisfactory level of immunity.3 Tests of significance were carried out using unpaired t tests. Of the 93 vaccinees tested, two were seronegative (no zone) by single radial haemolysis (table), although both had antibodies by radioimmunoassay (titres 20 and 320). One of these women had been among the group of eight with antibody values below 15 000 IU!I who had been challenged with RA27/3 intranasally in 1981. The remaining seven had antibody values exceeding 15 000 IU/I by both single radial haemolysis and radioimmuno-assay when tested two years after challenge. Eight to 10 years after vaccination the geometric mean titre of To-336 vaccinees measured by radioimmuno-assay was higher than that of the other vaccine groups (table) but this difference was not significant (p > 0 05). Although volunteers given Cendehill vaccine 13-18 years previously had a lower geometric mean titre than those given the vaccine eight to 10 years before, this difference was not significant (p >0-05). The two groups of RA27/3 vaccinees had a similar geometric mean titre. Comment We were reassured to find that antibodies (>15 000 IU/1) had …