Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. e222 | www.pidj.com The Pediatric Infectious Disease Journal •  Volume 34, Number 9, September 2015 REVIEW ARTICLE Abstract: Pertussis has reemerged as a problem across the world. To bet- ter understand the nature of the resurgence, we reviewed recent epidemio- logic data and we report disease trends from across the world. Published epidemiologic data from January 2000 to July 2013 were obtained via PubMed searches and open-access websites. Data on vaccine coverage and reported pertussis cases from 2000 through 2012 from the 6 World Health Organization regions were also reviewed. Findings are confounded not only by the lack of systematic and comparable observations in many areas of the world but also by the cyclic nature of pertussis with peaks occur- ring every 3–5 years. It appears that pertussis incidence has increased in school-age children in North America and western Europe, where acellu- lar pertussis vaccines are used, but an increase has also occurred in some countries that use whole-cell vaccines. Worldwide, pertussis remains a serious health concern, especially for infants, who bear the greatest dis- ease burden. Factors that may contribute to the resurgence include lack of booster immunizations, low vaccine coverage, improved diagnostic methods, and genetic changes in the organism. To better understand the epidemiology of pertussis and optimize disease control, it is important to improve surveillance worldwide, irrespective of pertussis vaccine types and schedules used in each country. Key Words: pertussis, epidemiology, acellular vaccines, whole-cell vaccine (Pediatr Infect Dis J 2015;34:e222–e232) P ertussis is vaccine-preventable, and 2 types of vaccines exist: whole-cell pertussis (wP), containing the entire inactivated Bor- detella pertussis organism, and acellular pertussis (aP). The aP vaccines were developed because of concerns about adverse reac- tions associated with wP vaccines. Since the 1980s, aP vaccines have replaced wP vaccines in many industrialized countries; however, in developing countries wP vaccines are still used for primary vaccination doses, mainly because of their lower cost. Despite routine and widespread vaccination, pertussis remains a significant public health issue. Moreover, in some countries with high vaccination coverage, a resurgence in pertussis has occurred. 1,2 Many hypotheses for the resurgence are postulated, including improved surveillance, diagnostic methods and disease awareness, but also incomplete vaccination, waning vaccine- induced or natural infection-induced immunity and the adapt- ability of the bacteria to immunity conferred by the vaccines. 1–8 Worldwide, infants bear the greatest disease burden and mor- tality, so preventing pertussis is an important public health goal. 9 Because optimal vaccination recommendations are predicated on accurate epidemiologic data, and in light of the recent resurgence, our goals in this article are to (1) review published epidemiologic data from January 2000 to July 2013 and report disease trends across the world, and (2) present data on vaccine coverage and reported per- tussis cases between 2000 and 2012 from the 6 World Health Organi- zation (WHO) defined regions (Africa, the Americas, the eastern Mediterranean, Europe, southeast Asia and the western Pacific). SEARCH STRATEGY AND COLLECTION CRITERIA Data were identified from PubMed searches and open- access websites. The predefined PubMed search criteria were employed not only to assure that the articles would be generated in an objective manner but also to guarantee that a manageable num- ber of relevant articles would be identified. The PubMed search used the keywords in the following format: (pertussis[Title] AND prevalence[Title]) OR (pertussis[Title] AND incidence[Title]) OR (pertussis[Title] AND epidemiology[Title]) AND (“2000/01/01”[PDat]: “2013/06/17”[PDat]) NOT Review. Only articles published between January 1, 2000, and July 13, 2013, containing data from 2000 onward were included. Articles were excluded if the data contained within were published before 2000, or if the content was not directly related to epidemiology. After the search, a lack of data from certain countries was noted and subsequent country-specific searches were conducted; in addition, country-specific sources were added from the authors. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0891-3668/15/3409-e222 DOI: 10.1097/INF.0000000000000795 Pertussis Across the Globe Recent Epidemiologic Trends From 2000 to 2013 Tina Tan, MD,* Tine Dalby, PhD,† Kevin Forsyth, MD,‡ Scott A. Halperin, MD,§ Ulrich Heininger, MD,¶ Daniela Hozbor, MD,║ Stanley Plotkin, MD,** Rolando Ulloa-Gutierrez, MD,†† and Carl Heinz Wirsing von König, MD,‡‡ Accepted for publication June 8, 2015. *Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL; †Department of Immunology, Microbiology, and Molecular Biol- ogy, Statens Serum Institut, Copenhagen, Denmark; ‡Department of Pediatrics, Flinders University, Adelaide, Australia; §Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada; ¶Department of Pediatrics, University Children’s Hospital (UKBB), University of Basel, Basel, Switzerland; ║Depart- ment of Pediatrics, Laboratorio VacSal, Instituto de Biotecnología y Biología Molecular (IBBM), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT-CONICET La Plata, Argentina; **Department of Pediatrics, Uni- versity of Pennsylvania, Philadelphia, PA; ††Department of Pediatrics, Hospital Nacional de Niños de Costa Rica “Dr. Carlos Sáenz Herrera,” San José, Costa Rica; and ‡‡Labor:Medizin Krefeld MVZ, Krefeld, Germany. T.T. has received grants from Merck & Co. and Sanofi Pasteur, personal fees from GlaxoSmithKline Biologicals and Sanofi Pasteur, and fees for participating in data safety monitoring boards from Pfizer Wyeth and Biota. S.A.H. has received grants, speaker honoraria, and personal fees for conducting clinical trials and participating in advisory boards from Sanofi Pasteur Inc, GlaxoS- mithKline Biologicals, Merck & Co., Novartis Vaccines and Diagnostics, and Pfizer Canada Inc. R.U.G. has received honorary fees for attending pertus- sis-related conferences and advisory boards from Sanofi Pasteur and Glax- oSmithKline. S.P. is a paid consultant to Sanofi Pasteur, Merck & Co, and GlaxoSmithKline Biologicals. C.H.W.v.K. has received honoraria for attend- ing meetings sponsored by Sanofi Pasteur, GlaxoSmithKline Biologicals SA, and Novartis Vaccines. K.F. has received grants from Sanofi Pasteur. T.D. and D.H. have nothing to disclose. U.H. has received personal fees from both Sanofi Pasteur and GlaxoSmithKline Biologicals SA. Medical writing support was funded by Sanofi Pasteur. The Global Pertussis Initiative is supported by Sanofi Pasteur SA and was established in 2001 to evaluate the on-going prob- lem of pertussis worldwide and to recommend appropriate pertussis control strategies. Sanofi Pasteur continues to fund this important initiative to provide a forum for scientific and policy-based discussions. The views and opinions expressed in this publication, which could include use of Sanofi Pasteur prod- ucts that is inconsistent with current labeling or licensed indication, are solely those of the authors and do not reflect the position of Sanofi Pasteur SA. Address for correspondence: Tina Tan, MD, Ann & Robert H. Lurie Children’s Hospital, 225 E. Chicago Ave, Box 20, Chicago, IL 60611. E-mail: ttan@ northwestern.edu.