Carrageenan Nasal Spray and Probiotic Lozenges to Prevent Flu-Like Illness in Healthcare Workers: A Pragmatic Field Study at the Arbaeen Mass Gathering

Ghanei, Ali; Eslami Mahmoodabadi, Mostafa; Abdolrashidi, Mahdi; Peypar, Mohammad Hossein; Rashidi, Mohammad Hamed; Nikkhah, Alireza; Ghanei, Mostafa; Bagheri, Hassan; Salesi, Mahmood

doi:10.30491/ijtmgh.2026.578763.1525

Carrageenan Nasal Spray and Probiotic Lozenges to Prevent Flu-Like Illness in Healthcare Workers: A Pragmatic Field Study at the Arbaeen Mass Gathering

Document Type : Original Article

Authors

Ali Ghanei ¹

Mostafa Eslami Mahmoodabadi ²

Mahdi Abdolrashidi ²

Mohammad Hossein Peypar ²

Mohammad Hamed Rashidi ²

Alireza Nikkhah ²

Mostafa Ghanei ³

Hassan Bagheri ⁴

Mahmood Salesi ⁴

¹ Research Center for Health Management in Mass Gathering, Red Crescent Society of the Islamic Republic of Iran, Tehran, Iran.

² Student Research Committee, Baqiyatallah University of Medical Sciences, Tehran, Iran.

³ Chemical Injuries Research Center, Systems Biology and Poisonings Institute Baqiyatallah University of Medical Sciences, Tehran, Iran

⁴ Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.

10.30491/ijtmgh.2026.578763.1525

Abstract

Background: The Arbaeen pilgrimage is among the world’s largest mass gatherings and is associated with a high burden of respiratory and gastrointestinal infections. Practical, low-cost prophylactic measures suitable for crowded, resource-constrained settings are needed. Oral probiotics and nasal barrier agents may offer a feasible approach.
Methods: We conducted a pragmatic, open-label field intervention study across 10 health centers (Mawkibs) in Najaf, along the Najaf–Karbala walking route, and in Karbala during Arbaeen 2023. Healthcare workers aged 16–70 years received carrageenan nasal spray, Streptococcus salivarius lozenges (K12/M18), the combination, or no intervention (control), according to operational feasibility at each site. Self-reported gastro-respiratory symptoms (GIRS: fever, cough, sore throat, runny nose, diarrhea, vomiting) were collected by telephone on day 25 to capture symptoms within the Arbaeen target period. Analyses used Chi-square/Fisher’s exact tests, Kruskal–Wallis, and age- and sex-adjusted logistic regression (two-sided p≤0.05).
Results: A total of 222 participants were included and analyzed (control n=106; intervention n=116: lozenge n=19, spray n=60, combination n=37). Mean reported product use was 5.36 days. Compared with control, the combination arm showed lower odds of fever (OR 0.114; 95% CI 0.045–0.291), cough (OR 0.183; 95% CI 0.075–0.446), and sore throat (OR 0.174; 95% CI 0.074–0.406). Diarrhea and vomiting were not significantly different. No serious adverse events were reported.
Conclusions: In this real-world setting, combined carrageenan spray and S. salivarius lozenges were associated with lower odds of flu-like symptoms among healthcare workers. Findings are exploratory and should be confirmed in larger placebo-controlled studies.

Keywords

Mass gathering

Arbaeen

Infection prevention

Field intervention

Respiratory infection

Travel medicine