Social & Preventive Medicine Denominator while calculating secondary attack rate following a person with a primary disease is: March 2009 A All the contacts who are exposed to the affected person B All the people in his home C All the people in his family D All the people in his city 💡 Explanation Denominator while calculating secondary attack rate following a person with a primary disease is: March 2009 ✓ Correct Answer: A. All the contacts who are exposed to the affected person