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. 2025 Oct;91(4):106558.
doi: 10.1016/j.jinf.2025.106558. Epub 2025 Jul 21.

Umrah- and travel-associated meningococcal disease due to multiple serogroup W ST-11 sub-strains pre-Hajj 2024

Jay Lucidarme  1 , Ala-Eddine Deghmane  2 , Shalabh Sharma  3 , Courtney Meilleur  4 , Lorraine Eriksson  5 , Paula Mölling  5 , Heike Claus  6 , Nina M van Sorge  7 , Célia Bettencourt  8 , Paula Bajanca-Lavado  8 , Raymond S W Tsang  4 , Dominique A Caugant  9 , Paola Stefanelli  10 , Arianna Neri  10 , Georgina Tzanakaki  11 , Aiswarya Lekshmi  12 , Helen Campbell  13 , Stephen A Clark  12 , Emma J Heymer  13 , Sonia Ribeiro  13 , Laura Willerton  12 , Lloyd Walsh  12 , Xilian Bai  12 , Thiên-Trí Lâm  6 , Basanta R Wagle  14 , Vishakh Walia  14 , Rebecca L Howie  3 , John Neatherlin  3 , Amy Rubis  3 , Madhura Vachon  3 , Lucy A McNamara  3 , Shamez N Ladhani  15 , Muhamed-Kheir Taha  2 , Ray Borrow  12
Affiliations
Free article

Umrah- and travel-associated meningococcal disease due to multiple serogroup W ST-11 sub-strains pre-Hajj 2024

Jay Lucidarme et al. J Infect. 2025 Oct.
Free article

Abstract

Objectives: Collectively, the Hajj and Umrah pilgrimages draw >30 million pilgrims to the Kingdom of Saudi Arabia (KSA) each year. Before Hajj 2024 (14 to 19 June), the meningococcal serogroup W ST-11 complex (W:cc11) Hajj-strain sublineage caused multiple international cases of invasive meningococcal disease (IMD) associated with travel to the Middle East and Asia. Here we identify and characterise the strains responsible.

Methods: All Hajj strain sublineage genomes on PubMLST.org underwent core genome MLST comparisons (PubMLST.org).

Results: Isolates from 30 cases, across seven countries, formed five phylogenetic clusters within two distinct strains. Travel histories included KSA, other Middle Eastern countries, India, Mauritius, Kenya via Turkey, and no known associated travel. The prevalent strain, representing four clusters, had no African, and limited Middle Eastern, representation. The geo-temporal distribution of available genomes indicated Eastern Europe as a possible source.

Conclusions: The rapid expansion of Umrah/travel-related W:cc11 IMD cases in early 2024 was due to multiple strains/sublineages. Despite the involvement of non-KSA travel-destinations, the coincidence of cases with the busy month of Ramadan, and the abrupt cessation during Hajj (when vaccine compliance is maximal), suggest that Umrah was a key driver and highlight the need to reinforce mandatory vaccination whilst maintaining global vigilance.

Keywords: Hajj; Hajj strain sublineage; Meningococcal serogroup W; Outbreak; ST-11 clonal complex; Umrah.

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Conflict of interest statement

Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: JL, AL, SAC, LW, LlW, XB, and RB perform contract work on behalf of UKHSA for GSK, PATH, Pfizer and Sanofi. SNL performs contract work on behalf of St. George’s University of London for vaccine manufacturers. The Immunisation and Vaccine Preventable Diseases Division at UKHSA (authors EJH, HC, SR and SNL) has provided vaccine manufacturers with post-marketing surveillance reports on meningococcal, Haemophilus influenzae, and pneumococcal infections, which the companies are required to submit to the UK Licensing Authority in compliance with their risk management strategy. A cost recovery charge is made for these reports. M-K. Taha performs contract work for the Institut Pasteur funded by GSK, Pfizer and Sanofi and has a patent NZ630133A Patent with GSK “Vaccines for serogroup X meningococcus” issued. AD, SS, CM, LE, PM, HCl, NMvS, CB, PBL, RSWT, DAC, PS, AN, GT, TTL, BRW, VW, RLH, JN, AR, MV, LAM, declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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