There are two types of vaccines for the ‘pneumonia jab’ Streptococcus Pneumoniae (pneumococcus).  Pneumovax is a vaccine prepared from a mixture of 23 bacterial polysaccharide (sugar) components which is effective in older children and adults. This is used to protect those that have sickle cell disease or have had their spleen removed, to prevent chest and sinus infections. This safe vaccine may be used to test for antibody production as part of the investigation of a suspected immunodeficiency.
Children under the age of two do not respond to the polysaccharide vaccines. To protect this group of high-risk individuals, conjugated pneumococcal vaccines were introduced universally in the UK in 2006. These vaccines are also composed of bacterial components and contain no live organisms; they are safe in immunodeficient patients and may be used to investigate suspected immunodeficiency.
You may also find this IPOPI booklet on vaccines useful.