Reducing the Dose of Smallpox Vaccine Reduces Vaccine‐Associated Morbidity without Reducing Vaccination Success Rates or Immune Responses

Robert B. Couch, Patricia Winokur, Kathryn M. Edwards, Steven Black, Robert L. Atmar, Jack T. Stapleton, Jennifer M. Kissner, Henry Shinefield, Thomas N. Denny, Michael J. Bybel, Frances K. Newman, Lihan Yan
2007 Journal of Infectious Diseases  
Background. When the decision was made to prepare for a deliberate release of smallpox, the United States had ∼15 million doses of Wyeth Dryvax vaccine, which was known to induce significant morbidity when used undiluted; Sanofi Pasteur, Inc., later identified ∼85 million additional doses in storage. Methods. Eleven vaccine-dose groups, each with 30 vaccinia-naive subjects, were given diluted Dryvax vaccine or 1 of 2 lots of Sanofi Pasteur smallpox vaccine and were evaluated for vaccination
more » ... for vaccination success rates, morbidity, and immune responses. Results. Estimated doses of 10 6.6 -10 8.2 pfu of virus/mL induced major reactions (or "takes") in 93%-100% of subjects in each dose group. No differences in vaccination take rates, lesion size, erythema, and induration or in serum neutralizing-antibody response were detected between the groups. However, systemic reactogenicity and missed activities were significantly lower for the vaccine groups given doses of 10 6.6 -10 7.2 pfu/mL than for those given doses of 10 7.6 -10 8.2 pfu/mL. Conclusions. These findings support the use of a higher dilution of Wyeth Dryvax vaccine and Sanofi Pasteur smallpox vaccine, given that the resulting morbidity should be significantly lower without loss of vaccine effectiveness. A plan for use of higher dilutions would create an enormous stockpile of vaccine.
doi:10.1086/511828 pmid:17299712 fatcat:2q4o2w4gabh55gfxpjw4y7yglm