Effect of Treatment of Thyrotoxicosis on Exophthalmos.

28 days of onset of symptoms, were reported. Residual paralysis was found in only four cases of paralytic poliomyelitis occurring between 5 and 28 days after vaccination, an incidence of 1 in four and a half million doses administered. Three of the four were infants: there was no evidence, as in the United States, of a higher incidence in adults. No particular vaccine batches were implicated. Studies of the age, sex, and geographical distribution of cases and of their vaccination histories did not reveal any important differences between vaccine-associated and other cases. It is considered unlikely that disease was caused by spread of vaccine virus to contacts of vaccinated persons. Type 3 poliovirus was isolated proportionately more often from vaccine-associated than from other cases, but this finding was not unexpected after administration of vaccine containing all three virus types. The frequency of isolation of poliovirus from other cases of paralytic poliomyelitis fell between 1962 and 1963-4, suggesting that a greater proportion of cases diagnosed as poliomyelitis in the later years may not have been due to infection with poliovirus. It is concluded that the risk, if any, of the vaccine causing serious disease was extremely small, and, in view of the benefits conferred by vaccination, it did not justify any change in the present recommendations for the use of oral (Sabin) vaccine. We are indebted to the many medical officers of health, hospital clinicians, general practitioners, and virologists who have co-operated in providing information concerning their patients, and to the Ministry of Health for the statistics on the use of oral vaccine.