VZV Foundation - A Decade Of Leadership In The Fight Against VZV Infections

	Oral Presentation Abstracts: 21 [21] VACCINATION OF 12-YEAR OLD VARICELLA HISTORY NEGATIVE SCHOOL-CHILDREN WITH VZV-VACCINE CONCOMITANT WITH MMR-VACCINATION IN STOCKHOLM, SWEDEN *P.A.Parment (1), G.Bråkenhielm (2), A.Linde (3), U.Rudén (3), J.Storsæter (4), A.Svahn (3) (1) Department of Communicable Disease Control & Prevention, Stockholm, Sweden; (2) School Health Care, Stockholm, Sweden; (3)Department of Virology, Swedish Institute for Infectious Disease Control, Solna, Sweden; (4)SmithKline Beecham AB, Solna, Sweden In order to investigate the rate of Varicella-Zoster virus (VZV) seronegativity in relation to history in 12-year old school children, and the rate of sero-conversion after VZV vaccination concomitant with MMR booster, the parents of 1231 twelve years old children in Stockholm were asked for VZV history, and if they accepted varicella vaccination (Varilrix®) at the same time as MMR (MMR® II). Serum-samples were obtained before and at 8 weeks after vaccination from VZV-vaccinated children and from a control-group of history positive children given MMR booster only. The presence of VZV antibodies and changes of VZV sero-status were determined in by a commercial IFA (Virgo IF Kit) and by ELISA (Enzygnost, Dade Behring). Of the 1,231 children asked, 190 (15%) lacked VZV-history. Of the 62 history-negative children who allowed sampling, 12 (19%) lacked antibodies, giving a maximum of 3% seronegative children at 12 years of age. All history-positive children had VZV-antibodies. The study was prolonged one year and totally 92 VZV history negative and 184 control children were included. Before vaccination 17/92 (18%) proved VZV seronegative, and 12/17 (71%) seroconverted. The non-responders are currently being reinvestigated for antibodies and T4-memory cells to VZV, as well as revaccinated. The response of the MMR booster was not affected by the VZV-vaccination. Lack of history of varicella can not be used as a criterion for VZV-vaccination for 12-year old children, and blood test for VZV-serology prior to decision for vaccination is cost-effective. The seroconversion rate after one dose of the VZV-vaccine in 12-year old children is similar to that of adults, and two doses of VZV-vaccine seems to be necessary. Corresponding Author: P.A.Parment, M.D., Ph.D., Department of Communicable Disease Control and Prevention, Norrbacka 4th floor, Karolinska Hospital, S-171 76 Stockholm, Sweden

[21]

VACCINATION OF 12-YEAR OLD VARICELLA HISTORY NEGATIVE SCHOOL-CHILDREN WITH VZV-VACCINE CONCOMITANT WITH MMR-VACCINATION IN STOCKHOLM, SWEDEN

*P.A.Parment (1), G.Bråkenhielm (2), A.Linde (3), U.Rudén (3), J.Storsæter (4), A.Svahn (3) (1) Department of Communicable Disease Control & Prevention, Stockholm, Sweden; (2) School Health Care, Stockholm, Sweden; (3)Department of Virology, Swedish Institute for Infectious Disease Control, Solna, Sweden; (4)SmithKline Beecham AB, Solna, Sweden

In order to investigate the rate of Varicella-Zoster virus (VZV) seronegativity in relation to history in 12-year old school children, and the rate of sero-conversion after VZV vaccination concomitant with MMR booster, the parents of 1231 twelve years old children in Stockholm were asked for VZV history, and if they accepted varicella vaccination (Varilrix®) at the same time as MMR (MMR® II). Serum-samples were obtained before and at 8 weeks after vaccination from VZV-vaccinated children and from a control-group of history positive children given MMR booster only. The presence of VZV antibodies and changes of VZV sero-status were determined in by a commercial IFA (Virgo IF Kit) and by ELISA (Enzygnost, Dade Behring). Of the 1,231 children asked, 190 (15%) lacked VZV-history. Of the 62 history-negative children who allowed sampling, 12 (19%) lacked antibodies, giving a maximum of 3% seronegative children at 12 years of age. All history-positive children had VZV-antibodies. The study was prolonged one year and totally 92 VZV history negative and 184 control children were included. Before vaccination 17/92 (18%) proved VZV seronegative, and 12/17 (71%) seroconverted. The non-responders are currently being reinvestigated for antibodies and T4-memory cells to VZV, as well as revaccinated. The response of the MMR booster was not affected by the VZV-vaccination. Lack of history of varicella can not be used as a criterion for VZV-vaccination for 12-year old children, and blood test for VZV-serology prior to decision for vaccination is cost-effective. The seroconversion rate after one dose of the VZV-vaccine in 12-year old children is similar to that of adults, and two doses of VZV-vaccine seems to be necessary.

Corresponding Author: P.A.Parment, M.D., Ph.D., Department of Communicable Disease Control and Prevention, Norrbacka 4th floor, Karolinska Hospital, S-171 76 Stockholm, Sweden