Impact of the Hajj on pneumococcal carriage and the effect of various pneumococcal vaccines

Publication date: Available online 7 August 2017
Source:Vaccine
Author(s): Sophie Edouard, Jaffar A. Al-Tawfiq, Ziad A. Memish, Saber Yezli, Philippe Gautret
BackgroundThe Islamic Hajj pilgrimage is the largest annual mass gathering in the world. The overcrowding of people promotes the acquisition, spread and transmission of respiratory pathogens, including Streptococcus pneumoniae. It is estimated that about 33% of pilgrims are at risk of invasive pneumococcal disease.MethodsWe conducted a methodological review according to the Preferred Reporting Items for Systematic Reviews and meta-Analysis guidelines. The objective was to summarize the available data regarding the prevalence of pneumococcal carriage among Hajj pilgrims and about carriage acquisition and circulation of S. pneumoniae among pilgrims before and after participating in the Hajj according to their vaccination status.ResultsFive articles met eligibility criteria for pneumococcal carriage and impact of pneumococcal vaccination on carriage. All five studies showed a significant increase in nasopharyngeal carriage of pneumococci following the pilgrimage, with acquisition rates ranging from 18% to 36%. Serotypes 3, 19F and 34 are the most common. A significant increase in at least one antibiotic and multiple antibiotic non-susceptible strains was observed following participation in the Hajj. A lower prevalence was found in pilgrims treated with antibiotics, those who used a hand sanitizer, or those who washed their hands more frequently than usual. An increased carriage of pneumococcal serotypes included in pneumococcal vaccines (10-valent pneumococcal conjugate vaccine (PCV10), 13-valent pneumococcal conjugate vaccine (PCV13), 23-valent pneumococcal polysaccharide vaccine (PPV23) was observed following participation in the Hajj. To date, no study has shown a significant reduction in pneumococcal carriage among pilgrims after vaccination with PPV23 or PCVs. In fact, no significant difference was currently observed in the prevalence ratio of pneumococcal carriage between vaccinated and unvaccinated pilgrims.ConclusionThe studies analyzed in this review showed an increased carriage of pneumococcus in post-Hajj pilgrims compared to pre-Hajj pilgrims, including vaccine serotypes. Further studies are needed to investigate the possible relationships between carriage, disease and vaccine in pilgrims.



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