Evaluation of two kinds of smallpox vaccine: CVI-78 and calf lymph vaccine. I. Clinical and serologic response to primary vaccination.

A comparative study of two smallpox vaccines, standard calf lymph vaccine, and an attenuated vaccine, CVI-78, was performed in 95 children. Primary vaccination with CVI-78 resulted in a more attenuated response than primary vaccination with standard vaccine. Sixty-one percent of those vaccinated with CVI-78 and 96 percent of those vaccinated with standard vaccine developed a major dermal reaction; 16 percent of those vaccinated with CVI-78 and 89 percent of those vaccinated with standard vaccine developed post-vaccination neutralizing antibodies. Twenty-seven percent of the children vaccinated with CVI-78 demonstrated neither a dermal nor serologic postvaccination response, whereas only 2 percent of those vaccinated with standard vaccination demonstrated no postvaccination response.