Malawi shifts vaccine strategy to boost herd immunity against pneumonia

This study in Blantyre, Malawi, compares two schedules of the pneumococcal conjugate vaccine (PCV13): the current 3-dose schedule without a booster (3+0) versus a 2-dose schedule with a booster at 9 months (2+1). The goal is to see if the booster reduces carriage of vaccine-type pneumococcal bacteria in children and adults, thereby improving herd immunity. Over 3,500 participants, including children and HIV-infected adults, will have nasopharyngeal swabs taken to measure bacterial carriage. Results will help Malawi's health officials decide whether to change the national vaccine schedule.