A top health official has said the poison was very potent and “did not degrade quickly.”
“You can assume it is not much different now from the day it was distributed,” Ian Boyd, the chief scientific adviser at the British Department for Environment, Food and Rural Affairs, told Salisbury residents at a meeting on April 19.
Mr. Guthrie said the substrate — which, in a contact poisoning, could be a substance like hand cream or petroleum jelly — may have prevented the nerve agent from entering the victims’ bloodstream in a fatal dose. He said the authorities had released no information about the substrate that was used.
“Clearly, the method of putting it through the skin didn’t kill them,” he said.
Alastair Hay, professor of environmental toxicology at Leeds University, said the exposure “would have killed them if they hadn’t had the right treatment.”
“I have it on good authority that the symptoms were recognized by the medical staff very early, and that enabled them to institute treatment promptly,” he said. He added that the attacker may have expected the two to lose consciousness and die inside the house.
“They wouldn’t have been found if they had stayed inside,” Mr. Hay said.
While the British authorities were quick to state that the Skripals and a third person, Det. Sgt. Nick Bailey, who became ill during the investigation, were poisoned with novichok, the hospital has been more circumspect in describing their recovery.
Ms. Charles-Barks said that the rules regarding patient confidentiality meant that the hospital could not provide “detailed accounts” of how the three had been treated, and she instead offered only vague assessments.
“Treating people who are so acutely unwell, having been poisoned by nerve agents, requires stabilizing them, keeping them alive until their bodies could produce more enzymes to replace those that had been poisoned,” she said.
Lorna Wilkinson, the director of nursing at the hospital, said in a statement that Mr. Skripal’s release was an important milestone in his recovery, which would now continue with outpatient care.