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Original article

Vol. 151 No. 4950 (2021)

Decline of pertussis in hospitalised children following the introduction of immunisation in pregnancy – results from a nationwide, prospective surveillance study, 2013–2020

  • Jana Zumstein
  • Ulrich Heininger
Cite this as:
Swiss Med Wkly. 2021;151:w30064



AIMS OF THE STUDY: Surveillance of pertussis at a national level is important to collect information on the epidemiology of the disease and to design optimal immunisation strategies. After an initial surveillance period for pertussis in hospitalised children in Switzerland from 2006 to 2010, new recommendations (including immunisation in pregnancy) were implemented in the national pertussis immunisation schedule in 2013. To monitor its effects, surveillance was resumed in 2013 and concluded in 2020.

METHODS: From 1 January 2013 to 31 December 2020, hospitalised children under the age of 16 years with suspected or proven Bordetella pertussis infection were reported to the Swiss Paediatric Surveillance Unit. We analysed epidemiological and clinical characteristics for all patients who fulfilled the clinical case definition of pertussis (physician diagnosis, cough lasting ≥14 days in combination with at least one of the following symptoms: paroxysmal cough, whooping or post-tussive vomiting, or apnoea not otherwise explained in patients under the age of 12 months) with and without laboratory confirmation (polymerase chain reaction, culture or serology). 

RESULTS: 220 of the 306 reported cases met the inclusion criteria. Of these, 214 (97%) were laboratory-confirmed B. pertussis infections: 209 by polymerase chain reaction and 5 by culture from nasopharyngeal specimens. 172/220 (78%) patients were infants under six months of age at the day of hospitalisation. The mean annual hospitalisation rate for pertussis was 27.9 per 100,000 children for infants and 2.1 per 100,000 in all children <16 years of age. Of the 115 cases with precise records of immunisation, 50 (43%) were unimmunised, 3 (3%) were incompletely immunised and 62 (54%) were up to date with their immunisation status according to their age, including 10 (9%) whose next doses were due. However, most patients with an up-to-date immunisation status (85%) were still too young to have completed their primary series, leaving only eight cases of vaccine failure. Only 5 of the 172 infants <6 months of age had mothers who had been vaccinated during pregnancy.

CONCLUSIONS: After the introduction of immunisation in pregnancy in Switzerland, hospitalisation rates in infants declined. However, the remaining cases call for increased efforts towards more complete and timely immunisation of children, those in close contact with children, and pregnant women.


  1. Pertussis vaccines: WHO position paper - September 2015. Wkly Epidemiol Rec. 2015 Aug 28;90(35):433-58. English, French. PMID: 26320265.
  2. Guiso N, Wirsing von König CH. Surveillance of pertussis: methods and implementation. Expert Rev Anti Infect Ther. 2016 Jul;14(7):657–67.
  3. Forsyth KD, Tan T, von König CW, Heininger U, Chitkara AJ, Plotkin S. Recommendations to control pertussis prioritized relative to economies: A Global Pertussis Initiative update. Vaccine. 2018 Nov;36(48):7270–5.
  4. Heininger U, Weibel D, Richard JL. Prospective nationwide surveillance of hospitalizations due to pertussis in children, 2006-2010. Pediatr Infect Dis J. 2014 Feb;33(2):147–51.
  5. Federal Office of Public Health Switzerland. Anpassung der Impfempfehlung gegen Pertussis: für Jugendliche, Säuglinge in Betreuungseinrichtungen und und schwangere Frauen. Bull BAG. 2013 Feb;9:118–23.
  6. Zumstein J, Heininger U ; Swiss Paediatric Surveillance Unit. Clinical and Epidemiologic Characteristics of Pertussis in Hospitalized Children: A Prospective and Standardized Long-term Surveillance Study. Pediatr Infect Dis J. 2021 Jan;40(1):22–5.
  7. Brown LD, Cai TT, DasGupta A. Interval estimation for a binomial proportion. Stat Sci. 2001 May;16(2):101–33.
  8. Swiss Federal Statistical Office [Internet]. Basel: Demographic balance by age. [cited 2021 Apr 27]. Available from:
  9. Federal Office of Public Health Switzerland. Das neue «2 + 1- Impfschema» zur Basisimpfung von Säuglingen gegen Diphtherie, Tetanus, Pertussis, Poliomyelitis, Haemophilus influenzae Typ b und Hepatitis B: eine Dosis weniger. Bull BAG. 2019 Mar;13:18–22.
  10. Kuitunen I, Artama M, Mäkelä L, Backman K, Heiskanen-Kosma T, Renko M. Effect of Social Distancing Due to the COVID-19 Pandemic on the Incidence of Viral Respiratory Tract Infections in Children in Finland During Early 2020. Pediatr Infect Dis J. 2020 Dec;39(12):e423–7.
  11. Adlhoch C, Mook P, Lamb F, Ferland L, Melidou A, Amato-Gauci AJ, et al.; European Influenza Surveillance Network. Very little influenza in the WHO European Region during the 2020/21 season, weeks 40 2020 to 8 2021. Euro Surveill. 2021 Mar;26(11):2100221.
  12. Kitano T. The estimated burden of 15 vaccine-preventable diseases from 2008 to 2020 in Japan: A transition by the COVID-19 pandemic. J Infect Chemother. 2021 Oct;27(10):1482–8.
  13. Federal Office of Public Health Switzerland [Internet]. Basel: Sentinella – Aktuelle Meldungen. [cited 2021 Jul 17]. Available from:
  14. Urwyler P, Heininger U. Protecting newborns from pertussis - the challenge of complete cocooning. BMC Infect Dis. 2014 Jul;14(1):397.
  15. Erb ML, Erlanger TE, Heininger U. Child-parent immunization survey: how well are national immunization recommendations accepted by the target groups? Vaccine X. 2019 Mar;1:100013.
  16. Warfel JM, Zimmerman LI, Merkel TJ. Acellular pertussis vaccines protect against disease but fail to prevent infection and transmission in a nonhuman primate model. Proc Natl Acad Sci USA. 2014 Jan;111(2):787–92.
  17. Amirthalingam G, Andrews N, Campbell H, Ribeiro S, Kara E, Donegan K, et al. Effectiveness of maternal pertussis vaccination in England: an observational study. Lancet. 2014 Oct;384(9953):1521–8.
  18. Skoff TH, Blain AE, Watt J, Scherzinger K, McMahon M, Zansky SM, et al. Impact of the US Maternal Tetanus, Diphtheria, and Acellular Pertussis Vaccination Program on Preventing Pertussis in Infants <2 Months of Age: A Case-Control Evaluation. Clin Infect Dis. 2017 Nov;65(12):1977–83.
  19. Romanin V, Acosta AM, Juarez MD, Briere E, Sanchez SM, Cordoba BL, et al. Maternal Vaccination in Argentina: Tetanus, Diphtheria, and Acellular Pertussis Vaccine Effectiveness During Pregnancy in Preventing Pertussis in Infants <2 Months of Age. Clin Infect Dis. 2020 Jan;70(3):380–7.
  20. Heininger U. Is There a Need for a Stand-alone Acellular Pertussis Vaccine? Pediatr Infect Dis J. 2018 Apr;37(4):359–60.
  21. Heininger U, Klich K, Stehr K, Cherry JD. Clinical findings in Bordetella pertussis infections: results of a prospective multicenter surveillance study. Pediatrics. 1997 Dec;100(6):E10.
  22. Farizo KM, Cochi SL, Zell ER, Brink EW, Wassilak SG, Patriarca PA. Epidemiological features of pertussis in the United States, 1980-1989. Clin Infect Dis. 1992 Mar;14(3):708–19.
  23. Winter K, Zipprich J, Harriman K, Murray EL, Gornbein J, Hammer SJ, et al. Risk Factors Associated With Infant Deaths From Pertussis: A Case-Control Study. Clin Infect Dis. 2015 Oct;61(7):1099–106.

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