Question

When two live vaccines are not given at the same visit, the ideal minimum time gap between them is:

• A. 2 weeks
• B. 4 weeks
• C. 8 weeks
• D. 12 weeks

Hint:

If not given the same day, space two live vaccines by at least a month.

Answer 1

The Correct Option is B

Step 1: Recall the spacing rule for live vaccines - they may be co-administered on the same day, but if missed together they cannot be given just a few days apart. Step 2: The standard recommendation is to wait at least 4 weeks (28 days) before giving the second live parenteral or intranasal vaccine, which corresponds to option B. Step 3: The biological basis is transient interferon production triggered by the first live virus, which can blunt the replication and therefore the immunogenicity of a second live vaccine given within a few weeks. Step 4: Therefore 2 weeks is too short and 8 or 12 weeks exceeds the needed minimum; the ideal minimum gap is 4 weeks. \[\boxed{4\ \text{weeks}}\]