Thank you for your inquiry.
As you know, the maximum antibody titer after immunization with Pneumovax usually is reached by four weeks. It is possible that, should you redraw blood now, you might therefore see a significant rise in the intervening two to three weeks you have before the maximum titer is normally reached. I would therefore redraw the titers as soon as feasible.
You also, of course, would be able to assess whether this child was reacting normally by assessing the number of antigens showing a protective level of anti-pneumococcal titers. A protective or adequate response to a pneumococcal polysaccharide serotype is defined as a titer of 1.3 mcg/ml or higher. In a child from 24 months to 5 years of age, this protective level should be present in at least 50% of the serotypes evaluated (1).
Thank you again for your inquiry and we hope this response is helpful to you.
1.Ballow M. Use of vaccines in the evaluation of presumed immunodeficiency. Annals of Allergy, Asthma, and Immunology 2013 (September); 111(3):163-166.
Phil Lieberman, M.D.