In the past 50 years, mortality from botulism has fallen dramatically (from about 50% to 8%) because of advances in supportive care, which is the mainstay of treatment. The respiratory failure and paralysis that occur with severe botulism may require a patient to be on a ventilator for weeks, plus intensive medical and nursing care. After several weeks, the paralysis slowly improves. Recovery from botulism takes many weeks.
Although a minority of botulism patients eventually recover their pre-infection health, the majority do not. For those who fully recover, the greatest improvement in muscle strength occurs in the first three months after the acute phase of illness. The outside limit for such improvement appears, however, to be one year. Consequently, physical limitations that still exist beyond the one-year mark are—more probably than not—permanent. Recovery from acute botulism symptoms may also be followed by persistent psychological dysfunction that may require intervention.
According to a recently published study that tracked the long-term outcomes of 217 cases of botulism, a large majority of patients reported “significant health, functional, and psychosocial limitations that are likely the consequences of the illness.” These limitations included fatigue, weakness, dizziness, dry mouth, and difficulty lifting things. The victims also reported difficulty breathing caused by moderate exertions, such as walking or lifting heavy items. They were also more likely to have limitations in vigorous activities, like running or playing sports, climbing up three flights of stairs, or carrying groceries. Summarizing its findings, the study concluded that:
Even several years after acute illness, patients who had botulism were more likely than control subjects to experience fatigue, generalized weakness, dizziness, dry mouth, difficulty lifting things, and difficulty breathing caused by moderate exertion.... In addition, patients... reported worse overall psycho-social status than did control subjects, with patients being significantly less likely to report feeling happy, calm and peaceful, or full of pep.