Pneumococcal vaccine is prepared from -

Ans. is 'b' i.e.. Capsular polysaccharide Pneumaeoccal vaccineo There are two types of pneumococcal vaccines available : -Polyvalent (23 type) polysaccharide vaccineThis polysaccharide vaccine represents the capsular antigen of 23 most prevalent serotypes.It gives 80-90% protection which is long lasting (5 years).It is not meant for general use, but only in persons at enhanced risk of pneumococcal infection such as those with absent or dysfunctional spleen; sickle cell disease, coeliac disease; Chronic liver or renal or lung or cardiac disease, DM, CSF leaks (meningeal disruption: dural tear) and; immunodeficiency including HIV infection. It is not recommended in children under two years of age and those with lymphoreticular malignancies and immunosupprassive therapy.Conjugate vaccineA different pneumococcal vaccine containing pneumococcal polysaccharide coupled (conjugated) to a carrier protein (diphtheria toxoid) has been developed.The vaccine contains the capsular polysaccharide of seven most common pneumococcal serotypes.It can be given to children under the age of 2 years (but more than 6 weeks old).