Respiratory infections among pilgrims at the Grand Magal of Touba: A comparative cohort controlled survey.

Goumballa, Ndiaw; Hoang, Van Thuan; Perieres, Lauren; Anh Ly, Tran Duc; Gaye, Papa Mouhamadou; Diouf, Fatou Samba; Parola, Philippe; Sokhna, Cheikh; Gautret, Philippe

BACKGROUND The Grand Magal of Touba (GMT) is a large event gathering around 4-5 million participants every year. A pilot study conducted in 2017 among GMT pilgrims showed that 41.8% of participants reported respiratory symptoms, mostly due to rhinovirus (13.0%), coronaviruses (16.0%) and adenovirus (4.6%). METHODS A PCR-based prospective cohort study was conducted among GMT pilgrims and controls (who did not participate to the event) in two rural villages in South Senegal, in 2019. RESULTS 93 pilgrims and 84 controls were included in the study. There were no significant differences between pilgrims and controls regarding demographic characteristics and chronic conditions. 60.2% of pilgrims reported respiratory symptoms during their stay in Touba, or soon after their return. By contrast, only 8.3% of controls reported respiratory symptoms after the GMT. The acquisition of rhinovirus, coronaviruses, Streptococcus pneumoniae and Moraxella catarrhalis was 22.6%, 6.5%, 17.2% and 6.8% respectively in pilgrims and was significantly higher than in controls (3.6%, 0%, 4.8% and 1.2% respectively). Respiratory symptoms post-GMT were five times more frequent in S. pneumoniae carriers (aOR = 5.18, 95%CI = [1.98 - 13.57]). CONCLUSION This study demonstrates that individuals who participated in the GMT were at higher risk of suffering from respiratory symptoms and that this was linked to the acquisition of S. pneumoniae.