Reducing the dose of smallpox vaccine reduces vaccine-associated morbidity without reducing vaccination success rates or immune responses.
BACKGROUND: When the decision was made to prepare for a deliberate release of smallpox, the United States had approximately 15 million doses of Wyeth Dryvax vaccine, which was known to induce significant morbidity when used undiluted; Sanofi Pasteur, Inc., later identified approximately 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 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.
Duke Scholars
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- Variola virus
- Treatment Outcome
- Smallpox Vaccine
- Microbiology
- Male
- Humans
- Female
- Dose-Response Relationship, Drug
- Chorion
- Chick Embryo
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Variola virus
- Treatment Outcome
- Smallpox Vaccine
- Microbiology
- Male
- Humans
- Female
- Dose-Response Relationship, Drug
- Chorion
- Chick Embryo