A multicentre, randomized controlled trial using a two factorial design. Eighty patients will be randomly assigned to receive either Pneumovax (or Pneumo23 according to standard use at site) or heptavalent pneumococcal conjugate vaccine (Prevnar) prior to reconstitution of the immune system or will have immunization delayed until their CD4 count is greater than 200 cells/mm3 after the introduction of antiretroviral therapy. Randomization will be stratified by study centre. Variable block sizes will be used to try to prevent study personnel from guessing the next allocation. Random allocation lists will be generated by computer.