This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
Which of the following statements is true regarding peussis ? 
Select and explain. 
A. Neurological complication rate of DPT is I in 50000, B. Vaccine efficacy is more than 95%, C. Erythromycin prevents spread of disease between children, D. The degree of polymorphonuclear Leukocytosis correlates with the severity of cough
C: Erythromycin prevents spread of disease between children
Answer: C: Erythromycin prevents spread of disease between children 
Explanation: Ans. is 'c' i.e., Erythromycin prevents spread of disease between children o Efficacy of Peusis Vaccine - repoed to be from 70-90% o Risk of acute encephalopathy - is 1 in 40, 000 cases following DTP vaccine. o Peusis toxin produces Lymphocytosis & not polymorphonuclear Leukoctyosis. Leukocytosis due to absolute lymphocytosis is characteristic in late catarrhal or paraoxysmal stage. o Prophylactic erythromycin prevents infecting bacteria to become established - prevents spread of disease - Park