Clinical and immune responses after revaccination of israeli adults with the Lister strain of vaccinia virus.
BACKGROUND
During the winter of 2002-2003, the Israeli health authorities launched a campaign to vaccinate first responders against smallpox.


METHODS
In an open study, 159 healthy, preimmunized adults, 24-52 years old, who participated in the campaign were vaccinated with the Lister strain of vaccinia virus by the multipuncture technique. The safety, immunogenicity, and reactogenicity of the vaccine were assessed.


RESULTS
Successful vaccination rates were 61% and 56%, on the basis of clinical take and seroconversion, respectively. Adverse events among the vaccinees were minor. Seventy-nine (88%) of the 90 vaccinees with clinical take also seroconverted ( kappa =0.779). The level of preexisting antibodies inversely correlated with the rates of clinical take and seroconversion (P</=.0098). In the group of vaccinees with the lowest preexisting levels of antibodies, 89% and 86% developed clinical take or seroconverted, respectively. The time since last vaccination was significantly associated with the rates of clinical take and seroconversion (P</=0.001).


CONCLUSIONS
These rates of successful vaccination in previously immunized individuals are consistent with the historical experience of use of this vaccine in Israel. The rate of occurrence and the severity of local and other reactions in the vaccinees were within the expected range. Levels of preexisting antibodies and the time since last vaccination played a major role in determining success rates.
Orr
Nadav
N
Center for Vaccine Development and Evaluation, Israel Defense Force, and Department of Epidemiology and Preventive Medicine, Tel Aviv University, Ramat Aviv, Israel. naorr@012.net.il.
Forman
Moshe
M
Marcus
Hadar
H
Lustig
Shlomo
S
Paran
Nir
N
Grotto
Itamar
I
Klement
Eyal
E
Yehezkelli
Yoav
Y
Robin
Guy
G
Reuveny
Shaul
S
Shafferman
Avigdor
A
Cohen
Dani
D
D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012900:Smallpox Vaccine / Q000276:immunology*; D014611:Vaccination; D014616:Vaccinia virus / Q000276:immunology*
D000914:Antibodies, Viral; D012900:Smallpox Vaccine