Assessment of the prevention of secondary spread of whooping cough in clusters of group morbidity

Relevance. Secondary spread of pertussis in schools is driven by waning immunity by the age of 6–7 years, low clinical vigilance among healthcare workers regarding pertussis in over 5 years old, and close contact within organized groups. The scope and quality of anti-epidemic measures play a key role in the rapid containment of infection outbreaks.

Aims. To evaluate the effectiveness of anti-epidemic measures in cluster outbreaks of pertussis in schools across several regions of the Russian Federation.

Materials and Methods. Data from 36 geographically and temporally unlinked cluster outbreaks of pertussis across 9 regions of the Russian Federation in 2023 (the period of the highest incidence peak in 26 years) were analyzed. Standard reporting forms and custom-developed evaluation tables were utilized, capturing parameters such as outbreak duration, number of cases and contacts, laboratory testing coverage, and the timing and scope of implemented interventions (including the transition to remote learning).

Results. The mean duration of outbreak monitoring was 41 days (range: 21 to 88 days). In all outbreaks, anti-epidemic measures (isolation, medical surveillance, and room ventilation) were implemented promptly. The transition to remote learning was implemented in 14 outbreaks. A positive correlation was found between the number of cases and both the number of classes switched to remote learning (rs = 0.63, p < 0.001) and the timing of this transition (rs = 0.53, p = 0.001). This indicates that remote learning was resorted to out of necessity in large, prolonged outbreaks, when standard containment measures had already failed to yield results.

Conclusions. The prolonged duration and scale of outbreaks indicate a lack of immune protection among schoolchildren. Transitioning to remote learning is effective as an anti-epidemic measure only during the early stages of an outbreak. Monitoring and validation of clear criteria for evaluating the effectiveness of anti-epidemic measures in pertussis outbreaks are required. Medical surveillance and laboratory testing of exposed individuals are critical for the early detection of cases and their prompt removal from the school setting.

1. ECDC. Pertussis – Annual Epidemiological Report for 2024. Stockholm: European Centre for Disease Prevention and Control; 2026

2. Hua C.Z., He H.Q., Shu Q. Resurgence of pertussis: reasons and coping strategies. World Journal of Pediatrics. 2024;20:639–642. DOI: 10.1007/s12519-024-00821-2.

3. SanPiN 3.3686-21. Sanitary and epidemiological requirements for the prevention of infectious diseases. Sanitary and epidemiological rules and regulations : with amendments and additions dated February 11, May 25, 2022, June 25, 2025 : effective from 09/01/2021 Moscow, 2001. Available at: https://base.garant.ru/400342149/ (accessed on 01.05.2026). (In Russ.).

4. McNamara L.A., Skoff T., et al. High post-exposure prophylaxis uptake among household contacts of pertussis patients enrolled in a PEP effectiveness evaluation – United States, 2015–2017. PLOS ONE. 2023;18(5):e0285953. DOI: 10.1371/journal.pone.0285953.

5. UK Health Security Agency. Pertussis: guidelines for public health management. Updated 2024.

6. Minnesota Department of Health. Pertussis in Schools: information for schools and higher education on responding to cases of pertussis. Updated 2026.

7. UK Health Security Agency. Guidance on the management of cases of pertussis in England during the re-emergence of pertussis in 2024. – URL: https://www.gov.uk/government/publications/pertussis-guidelines-for-public-health-management (accessed: 20.07.2026).

8. Klein N.P., Bartlett J., Rowhani-Rahbar A., et al. Waning protection after fifth dose of acellular pertussis vaccine in children. New England Journal of Medicine. 2012;367:1012– 1019. DOI: 10.1056/NEJMoa1200850.

9. Kang H.M., Taek-Jin Lee, Su Eun Park, et al. Pertussis in the post-COVID-19 era: resurgence and changing epidemiology. Infection & Chemotherapy. 2025.

10. Liu Y., Daojun Yu, et al. Global resurgence of pertussis: a perspective from China. Journal of Infection. 2024

11. European Centre for Disease Prevention and Control. Increase of pertussis cases in the EU/EEA, 8 May 2024 Stockholm: ECDC; 2024. European Centre for Disease Prevention and Control, Stockholm, 2024. Catalogue number: TQ-02-24-500-EN-N, ISBN: 978-92-9498-717-4, DOI: 10.2900/831122

12. On the state of sanitary and epidemiological well-being of the population in the Russian Federation in 2024. State report. Moscow. 2025. – 424 p. (In Russ.). Available at: https://www.rospotrebnadzor.ru/upload/iblock/b8a/u6lsxjabw032jkdf837nlaezxu3ue09m/GD_SEB.pdf

13. Babachenko I. V., Nesterova Yu. V. Whooping Cough in Children and Adults in Family Homes. Poliklinika. 2023;5:67–71. (In Russ.).

14. Schwartz K.L., Kwong J.C., Deeks S.L., et al. Effectiveness of pertussis vaccination and duration of immunity. CMAJ. 2016;188(16):E399–E406. DOI: 10.1503/cmaj.160193.

15. СDC. Chapter 16: Pertussis. In: Epidemiology and Prevention of Vaccine-Preventable Diseases. The Pink Book. Updated 2024.

16. Khetsuriani N., Bisgard K., Prevots D.R., et al. Pertussis outbreak in an elementary school with high vaccination coverage. Pediatric Infectious Disease Journal. 2001;20(12):1108–1112.

17. Saul N, Wang K, Bag S, Baldwin H, et al. Effectiveness of maternal pertussis vaccination in preventing infection and disease in infants: The NSW Public Health Network casecontrol study. Vaccine. 2018 Mar 27;36(14):1887–1892. doi: 10.1016/j.vaccine.2018.02.047. Epub 2018 Mar 1. PMID: 29501321.