McCollum ED, Nambiar B, Deula R, Zadutsa B, Bondo A, King C, Beard J, Liyaya H, Mankhambo L, Lazzerini M, Makwenda C, Masache G, Bar-Zeev N, Kazembe PN, Mwansambo C, Lufesi N, Costello A, Armstrong B, Colbourn T. Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Clinical and Hypoxemic Childhood Pneumonia over Three Years in Central Malawi: An Observational Study. PLoS One 2017;12(1):e0168209.