 The two youngest children and the 23-year-old subsequently developed the haemorrhagic form of smallpox and died.The remaining individuals had previously been vaccinated, and all recovered after having an attenuated form of the disease.The high ratio of haemorrhagic smallpox cases in this outbreak, combined with the rate of infectivity and the testimony of General Burgasov, has led to the understanding that an enhanced weaponized strain of smallpox virus was released from Aralsk-7 in 1971.