Virus content of smallpox scabs

Log titres of smallpoxvirus (pock-forming units per 0.1 g of scab) were estimated in scabs from 5 patients from the 13th to the 24th days of illness. They were found to vary from 3.72 to 6.54 with no diminution as convalescence progressed, and they were not related to the primary vaccination status of the patient or the clinical severity of the disease.