Antibiotic use for respiratory infections among Hajj pilgrims: A cohort survey and review of the literature

Travel-related respiratory symptoms and infections in travellers (2000-22): a systematic review and meta-analysis

BACKGROUND

Respiratory tract infections (RTIs) are common in travellers due to the year-round or seasonal presence of respiratory pathogen and exposure to crowded environments during the itinerary. No study has systematically examined the burden of RTI infections among travellers. The aim of this systematic review and meta-analysis is to evaluate the prevalence of RTIs and symptoms suggestive of RTIs among travellers according to risk groups and/or geographic region, and to describe the spectrum of RTIs.

METHODS

The systematic review and meta-analysis was registered in PROSPERO (CRD42022311261). We searched Medline, Embase, Scopus, Cochrane Central, Web of Science, Science Direct and preprint servers MedRxiv, BioRxiv, SSRN and IEEE Xplore on 1 February 2022. Studies reporting RTIs or symptoms suggestive of RTIs in international travellers after 1 January 2000 were eligible. Data appraisal and extraction were performed by two authors, and proportional meta-analyses were used to obtain estimates of the prevalence of respiratory symptoms and RTIs in travellers and predefined risk groups.

FINDINGS

A total of 429 articles on travellers' illness were included. Included studies reported 86 841 symptoms suggestive of RTIs and 807 632 confirmed RTIs. Seventy-eight percent of reported respiratory symptoms and 60% of RTIs with available location data were acquired at mass gatherings events. Cough was the most common symptom suggestive of respiratory infections, and the upper respiratory tract was the most common site for RTIs in travellers. The prevalence of RTIs and respiratory symptoms suggestive of RTIs were 10% [8%; 14%] and 37% [27%; 48%], respectively, among travellers. Reporting of RTIs in travellers denoted by publication output was found to correlate with global waves of new respiratory infections.

INTERPRETATION

This study demonstrates a high burden of RTIs among travellers and indicates that travellers' RTIs reflect respiratory infection outbreaks. These findings have important implications for understanding and managing RTIs among travellers.

Respiratory pathogens among ill pilgrims and the potential benefit of using point-of-care rapid molecular diagnostic tools during the Hajj

We investigated respiratory pathogens among ill Hajj pilgrims from Marseille. We also discuss the potential role of point-of-care (POC) rapid molecular diagnostic tools for this purpose. Clinical data were collected using a standardised questionnaire. Influenza A and B viruses, human rhinovirus and human coronaviruses, Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae and Klebsiella pneumoniae were investigated using real-time PCR in respiratory samples obtained during travel, at the onset of symptoms. 207 participants were included. A cough, expectoration, rhinitis and a sore throat were the most frequent respiratory symptoms, followed by loss of voice and dyspnoea. 38.7% and 25.1% of pilgrims reported a fever and influenza-like symptoms, respectively. 59.4% pilgrims received antibiotics. Rhinovirus (40.6%) was the most frequent pathogen, followed by S. aureus (35.8%) and H. influenzae (30.4%). Virus and bacteria co-infections were identified in 28.5% of participants. 25.1% pilgrims who were positive for respiratory bacteria did not receive antibiotic treatment. In the context of the Hajj pilgrimage, it is important to detect infections that can be easily managed with appropriate treatment, and those that can affect prognosis, requiring hospitalisation. POC rapid molecular diagnostic tools could be used for patient management at small Hajj medical missions and to rationalise antibiotic consumption among Hajj pilgrims.

Transmission of Antimicrobial Resistant Bacteria at the Hajj: A Scoping Review

BACKGROUND

The Hajj is an annual religious mass gathering event held in Makkah, Saudi Arabia. With millions of participants from across the globe attending the Hajj, the risk of importation, transmission, and global spread of infectious diseases is high. The emergence of antimicrobial resistant (AMR) bacteria is of worldwide concern and the Hajj poses a serious risk to its dissemination. This review aims to synthesize published literature on AMR bacteria acquisition and transmission associated with the Hajj.

METHODS

We searched electronic databases to identify literature published between January 1990 and December 2021. The search strategy included medical subject headings and keyword terms related to AMR bacteria and the Hajj.

RESULTS

After screening 2214 search results, 51 studies were included in the analysis. The review found 6455 AMR bacteria transmissions related to the Hajj. Thirty predominantly enteric or respiratory disease-causing AMR bacterial species were reported with isolates identified in cases on five continents. Most were male, aged above 50 years and were diagnosed in Makkah. Most cases were identified through hospital-based research; few cases were detected in community or primary health care settings.

CONCLUSIONS

This review provides a contemporary account of knowledge related to AMR transmission at the Hajj. It emphasizes the need for the enhancement of surveillance for AMR bacteria globally.

Carriage of Neisseria meningitidis Among Umrah Pilgrims: Circulating Serogroups and Antibiotic Resistance

Background

Meningococcal disease and outbreaks are a risk during mass gatherings such as the Umrah religious pilgrimage to the Kingdom of Saudi Arabia (KSA). We aimed to investigate the carriage of Neisseria meningitidis among the 2019 Umrah pilgrims and determine the circulating serogroups and their antibiotic susceptibility profiles.

Methods

We conducted a cross-sectional study among adult Umrah pilgrims from 17th to 29th April 2019 in Mecca city, KSA. A questionnaire was administered to each participant, and an oropharyngeal swab was obtained. Microbiological techniques were used to isolate, identify and serogroup N. meningitidis from the swabs. E-tests were used to determine the susceptibility of the isolates to nine antibiotics.

Results

The study enrolled 616 pilgrims from 17 countries with a mean age of 53.8 years (±13.1, range = 19–91) and a male-to-female ratio of 1.1:1. Nearly 39% of the respondents had no formal education, 32.5% declared having an underlying health condition and 17.2% were current or past smokers. During their Umrah stay, most pilgrims reported sharing accommodation (98.5%) and never using a face mask (98.5%). Also, 34.6% reported suffering from influenza-like symptoms and 11.8% used antibiotics. N. meningitidis was isolated from three pilgrims (carriage rate of 0.49%), two were serogroup A and one was serogroup B. Antibiotic susceptibility results were available for one isolate (serogroup B) which showed resistance to ciprofloxacin and decreased susceptibility to trimethoprim-sulfamethoxazole.

Conclusion

Carriage of N. meningitidis among Umrah pilgrims was low. However, invasive serogroups were identified, including an isolate resistant to ciprofloxacin used for chemoprophylaxis. Meningococcal disease preventive measures for Umrah should be regularly reviewed and updated accordingly to reduce the risk of the disease and future pilgrimage-associated outbreaks.

Meningococcal Disease and Immunization Activities in Hajj and Umrah Pilgrimage: a review

Invasive meningococcal disease (IMD) outbreaks associated with Hajj and Umrah pilgrimage events in the Kingdom of Saudi Arabia (KSA) are well recognized. Past outbreaks have been associated with substantial intercontinental spread of specific Neisseria meningitidis serogroups. The emergence of meningococcal serogroup W (MenW) was a global concern following the 2000/2001 Hajj outbreaks. Broader compulsory meningococcal serogroups A, C, W and Y (MenACWY) immunization strategies for pilgrims were introduced in response to these events and led to substantial declines in IMD cases associated with these mass gatherings. However, there remains potential for future outbreaks either within KSA during the Hajj or in local populations via pilgrim meningococcal transmission on their return. While the annual Hajj involves pilgrims from over 185 countries, two-thirds of these arrive from 13 countries, chiefly from across South-East Asia, the Middle East and North African (MENA) regions; for which we review the relevant epidemiology of IMD and meningococcal carriage. While disease surveillance is limited and data are often lacking, MenB is an important serogroup associated with IMD and carriage in a number of countries. Available literature suggests that most pilgrims receive polysaccharide MenACWY vaccines (which do not impact carriage and onward transmission) and incomplete compliance with visa/entry immunization regulations is reported. Existing preventative approaches for visiting pilgrims require continued oversight. More complete compliance and switching to the conjugated MenACWY vaccine can provide more robust and broader protection for pilgrims. Additional immunization options could also be considered.

Evaluation of the rate, pattern and appropriateness of antibiotic prescription in a cohort of pilgrims suffering from upper respiratory tract infection during the 2018 Hajj season

Hajj is associated with an increased risk of the transmission of infectious diseases including upper respiratory tract infections (URTIs). It can be a focal point for the emergence, persistence and dissemination of antimicrobial-resistant (AMR) bacteria. The overuse of antibiotics during Hajj can promote the development of antimicrobial resistance. Little information is known regarding the true appropriateness of prescribing antibiotics for treating URTIs during Hajj. Here we studied the rate, patterns and appropriateness of antibiotic prescription among a cohort of pilgrims who were treated for URTIs during the 2018 Hajj season. Adult pilgrims who sought medical services for URTIs [presenting with coryza, runny nose, nasal irritation, nasal congestion, cough, sore throat, headache or fever (even if subjective)] within the Holy sites were enrolled in this study and consented to provide swabs and medical information. A total of 121 pilgrims were enrolled, with the majority (60.3 %) originating from North African Arab countries. Most were male (89.3 %) with a median age of 45 years. Bacterial infections were detected in 7.3 % (n=9) of the URTI cases. The identified bacteria included Haemophilus influenzae (n=6, all resistant to ampicillin), Streptococcus pneumoniae (n=2), Staphylococcus aureus (n=1, resistant to oxacillin) and Moraxella catarrhalis (n=1, resistant to ampicillin and trimethoprim/sulfamethoxazole). The antibiotic prescription rate was 52.1%, most of which was amoxicillin (81 %). The data demonstrated that the proportion of appropriate practices in treating bacterial URTIs in this cohort was 45.5 %. This study highlights the need for implementing laboratory identification of the aetiological agents and related AMR profiles when treating URTIs in Hajj, rather than relying on clinical assessment alone.

Pattern of utilization, disease presentation, and medication prescribing and dispensing at 51 primary healthcare centers during the Hajj mass gathering

Background

The majority of pilgrims seeking healthcare during Hajj are seen at primary healthcare centers (PHCCs). Data on the utilization of these facilities during Hajj can aid in directing optimal health services delivery and allocation of resources during the pilgrimage.

Method

We investigated the pattern of disease presentation, caseload, and medication prescribing and dispensing at 51 PHCCs during the 2019 Hajj. Data on patients’ demographics, diagnoses, and prescribed medications were retrieved from each PHCC’s electronic records and analyzed. Data were also used to calculate six of the World Health Organization (WHO) indicators for drug use at these facilities.

Results

Data were captured for 99,367 patients who were mostly Hajj pilgrims (95.4%), male (69.1%) from the Eastern Mediterranean (60.8%) and had a mean age of 46.6 years (SD = 14.9). Most patients (85.2%) were seen in Mina and towards the end of Hajj. The majority of patients (96.0%) had a single diagnosis; most commonly, respiratory (45.0%), musculoskeletal (17.2%), and skin (10.5%) diseases. Patients were prescribed 223,964 medications, mostly analgesics (25.1%), antibacterials for systemic use (16.5%), anti-inflammatory and antirheumatic products (16.4%), and cough and cold preparations (11.9%). On average, 2.25 (SD = 0.94) medications were prescribed per consultation, with low (1.3%) prevalence of polypharmacy. An antibiotic and an injectable were prescribed in 43.6 and 2.67% of patient encounters, respectively. Most (92.7%) of the prescribed drugs were actually dispensed, in an average time of 8.06 min (SD = 41.4). All PHCCs had a copy of the essential drugs list available, on which all the prescribed drugs appeared.

Conclusion

Respiratory illnesses are the main reason for PHCCs visits during Hajj, and analgesics and antibiotics are the most common medications prescribed to pilgrims. Our results, including the calculated WHO drug use indicators, contribute to evidence-based optimization of primary healthcare services during Hajj.

A Longitudinal Study Regarding the Health Profile of the 2017 South African Hajj Pilgrims

The Hajj mass gathering annually attracts over two million Muslim pilgrims worldwide to the Kingdom of Saudi Arabia (KSA). We aimed to establish demographics and health profiles for the South African pilgrims performing the 2017 Hajj. Methods: This is a longitudinal survey-based study conducted on 1138 adult South African pilgrims in two phases (during and post-Hajj). Data on demographics, vaccination status, underlying health conditions, pre-Hajj training, health promotion, travel history, and health issues during and post-Hajj were collected using pre-designed questionnaires. Results: Participants had a mean age of 49.2 years (SD = 13.3; range 18–81), with a male: female ratio of 1.2:1. The majority of pilgrims were married (88.2%), of Indian/Asian background (73%), and literate (>99%). Nearly all pilgrims were vaccinated against meningococcal disease and yellow fever, but only 23.7% were vaccinated against Influenza. Hypertension, diabetes, and elevated cholesterol levels were the most common underlying health conditions reported by 22.6%, 13.2%, and 11.5% of pilgrims, respectively. One month after return to South Africa, nearly 65% of pilgrims reported illness during Hajj, while 40% reported falling ill post event upon return to South Africa. Nevertheless, only a few were admitted to hospitals (12 during Hajj and 15 post-Hajj). Among ill pilgrims, respiratory symptoms were the most commonly experienced symptoms during (70.2%) and post-Hajj (82.2%). Other symptoms such as walking-related symptoms include symptoms directly related or mainly caused by walking (e.g., leg pain, sore feet, blisters on the feet), dehydration, and gastrointestinal tract symptoms reported during Hajj. Medication to treat respiratory symptoms and antibiotics were the most commonly used medications during and post-Hajj. Having an underlying health condition was an independent predictor of falling ill during or post Hajj. Conclusion: Our study indicates that a sizable proportion of South African pilgrims are elderly with underlying health conditions and most contract respiratory tract infections during and post Hajj. Our study highlights the need for systematic collection of prospective pilgrims’ demographics and health data and more attention to post-Hajj health follow-ups of pilgrims.

The Emergence, Persistence, and Dissemination of Antimicrobial-Resistant Bacteria in Environmental Hajj Settings and Implications for Public Health

The emergence of antimicrobial resistance is causing the loss of what was once considered the miracle cure. The transmission of antimicrobial resistance during mass gathering is a potential threat in addition to other infectious diseases. Here, we review the English language literature on the rate and the acquisition of antimicrobial resistance during the Hajj. There is a variable incidence of methicillin-resistant Staphylococcus aureus, Escherichia coli, and Enterobacteriaceae. There had been no report of multi-drug-resistant Mycobacterium tuberculosis. Continued surveillance of antimicrobial resistance coupled with public health measures are needed to decrease the rate of emergence of resistance.

Recent development of antibiotic detection in food and environment: the combination of sensors and nanomaterials

In recent years, the abuse of antibiotics has led to the pollution of soil and water environment, not only poultry husbandry and food manufacturing will be influenced to different degree, but also the human body will produce antibody. The detection of antibiotic content in production and life is imperative. In this review, we provide comprehensive information about chemical sensors and biosensors for antibiotic detection. We classify the currently reported antibiotic detection technologies into chromatography, mass spectrometry, capillary electrophoresis, optical detection, and electrochemistry, introduce some representative examples for each technology, and conclude the advantages and limitations. In particular, the optical and electrochemical methods based on nanomaterials are discussed and evaluated in detail. In addition, the latest research in the detection of antibiotics by photosensitive materials is discussed. Finally, we summarize the pros and cons of various antibiotic detection methods and present a discussion and outlook on the expansion of cross-scientific areas. The synthesis and application of optoelectronic nanomaterials and aptamer screening are discussed and prospected, and the future trends and potential impact of biosensors in antibiotic detection are outlined.Graphical abstract.

Hajj and Umrah Mass Gatherings and COVID-19 Infection

Purpose of Review

We discuss the risk of COVID-19 in religious mass gathering events including Hajj and Umrah pilgrimages.

Recent Findings

The risk of transmission of respiratory viruses including COVID-19 is particularly high due to the overcrowding conditions at the Hajj and Umrah. The profile of the Hajj pilgrims who tend to be older and with multiple comorbidities corresponds to that of individuals at risk for severe COVID-19. In order to avoid a COVID-19 outbreak with potential spreading to many countries through returning pilgrims, Saudi Arabia suspended the Umrah, and access to the 2020 Hajj was very limited.

Summary

A clear relation between early suspension of religious mass gatherings and lower occurrence of COVID-19 transmission in countries that took such measures promptly was noticed. There are lessons to national and international health organizations for other mass gatherings in the context of the pandemic.

Dynamics and genetic diversity of Haemophilus influenzae carriage among French pilgrims during the 2018 Hajj: A prospective cohort survey

BACKGROUND

To investigate the genetic diversity of Haemophilus influenzae positive samples among French pilgrims attending the 2018 Hajj pilgrimage.

METHOD

After screening by qPCR, multilocus sequence typing was performed for all H. influenzae-positive samples. The following housekeeping genes were amplified and assigned: adk, atpG, frdB, fucK, mdh, pgi and recA.

RESULTS

121 pilgrims were included. H. influenzae was positive in 35.5% pre-Hajj samples, 12.4% at day five post-arrival, 15.7% at day 12 post-arrival, and 43.0% post-Hajj. Of the 129 positive swabs for H. influenzae, only one sample at D12 was negative for all seven genes amplified by standard PCR. The adk, atpG, frdB, mdh, pgi, recA and fucK genes were positive in 123, 107, 122, 70, 127, 118 and 69 samples, respectively. One sequence of atpG and two of recA genes were not possible to assign. None of the sequences of fucK gene was successfully obtained. Consequently, a complete sequence type characterisation was not possible. Of the 128 obtained strains, 111 had distinct patterns of alleles.

CONCLUSION

H. influenzae genotypes acquired were completely different from those present at pre-Hajj. We observed a great biodiversity and a lack of clonality of H. influenzae among French pilgrims during the 2018 Hajj. Further studies aiming at studying the genome of Hajj-acquired H. influenzae isolates are needed to define the clinical burden of H. influenzae infection during Hajj and to evaluate the potential interest of vaccination in Hajj pilgrims.

Gastrointestinal symptoms and the acquisition of enteric pathogens in Hajj pilgrims: a 3-year prospective cohort study

The acquisition of enteric pathogens and risk factors for Hajj-associated diarrhea in Hajj pilgrims is poorly documented. Pilgrims from Marseille participating in the Hajj in 2016-2018 underwent successive systematic rectal swabbing before and after their travel. Carriage of the main enteric pathogens was assessed by real-time PCR. Baseline demographics, adherence to individual preventive measures, gastrointestinal symptoms, and treatments were recorded. A total of 376 pilgrims were included. The median age was 62.0 years. During the Hajj, 18.6% presented at least one gastrointestinal symptom, 13.8% had diarrhea, and 36.4% had acquired at least one enteric pathogen. Enteropathogenic Escherichia coli (EPEC) and Enteroaggregative E. coli (EAEC) were the pathogens most frequently acquired by pilgrims (17.6% and 14.4%, respectively). Being female was associated with increased frequency of gastrointestinal symptoms during the pilgrimage (aOR = 2.38, p = 0.004). Enterohemorrhagic Escherichia coli (EHEC) acquisition was associated with a four-fold higher risk of reporting at least one gastrointestinal symptom and diarrhea (aOR = 3.68 and p = 0.01 and aOR = 3.96 and p = 0.01, respectively). Pilgrims who suffered from diarrhea were more likely to wash their hands more often (aOR = 2.07, p = 0.03) and to be either overweight (aOR = 2.71, p = 0.03) or obese (aOR = 2.51, p = 0.05). Enteric bacteria such as E. coli that are frequently associated with traveler's diarrhea due to the consumption of contaminated food and drink were frequently found in pilgrims. Respecting strict measures regarding food and water quality during the Hajj and adherence to preventive measures such as good personal hygiene and environmental management will help reduce the burden of gastrointestinal infections at the event.

Medication utilization pattern among outpatients during the Hajj mass gathering

Background

The Kingdom of Saudi Arabia (KSA) provides free healthcare, including medications, for the over 2 million Muslim pilgrims who attend Hajj every year. Information on drug utilization patterns at the Hajj is important to strengthen the supply chain for medicines, avert stock-outs, identify inappropriate use, and support public health planning for the event.

Method

We investigated drug utilization pattern among outpatients in eight seasonal Holy sites hospitals in Makkah, KSA, during the 2018 Hajj. Data on medication prescribed and dispensed were retrieved from the hospitals' electronic records. Data were also used to calculate six of the WHO indicators for drug use at these facilities.

Results

A total of 99,117 medications were prescribed for 37,367 outpatients during 37,933 encounters. Outpatients were mainly older males and originated from 134 countries. Twenty medications accounted for 72.8% of the 323 different medications prescribed. These were mainly nonsteroidal anti-inflammatory drugs, analgesics and antipyretics, and antibacterial medicines for systemic use. Outpatients were prescribed an average of 2.6 (SD = 1.2) drugs per consultation and polypharmacy (≥5 medications) was observed in 4.8% of the encounters. Antibiotics and an injection were prescribed in 46.9% and 6.5% of encounters, respectively. Nearly 90% of the prescribed drugs were actually dispensed. On average, medications were dispensed 16.4 (SD = 119.8) minutes from the time they were prescribed for the patient. All hospitals had a copy of the essential drugs list available and all of the prescribed drugs appeared on that list.

Conclusion

Nonsteroidal anti-inflammatory drugs, analgesics and antibiotics are the most common medications prescribed to outpatient during Hajj. Our results, including the calculated WHO drug use indicators, can form a basis for further investigations into appropriate drug use at the Hajj and for planning purposes. These results could also guide the development of reference values for medications prescribing and use indicators at mass gatherings.

Senegal's Grand Magal of Touba: Syndromic Surveillance during the 2016 Mass Gathering

The Grand Magal of Touba (GMT) is an annual 1-day Muslim religious event that takes place in Touba in Senegal. The city of Touba swells from 800,000 to four million people during the GMT. All patients who attended one of the 154 dedicated medical care public healthcare structures of the medical region of Diourbel during the GMT were included in a cross-sectional survey from November 16 to November 21, 2016. Demographic, morbidity, and mortality data were collected on a daily basis using a standardized article form that allows data to be recorded in a free-text format. Data were obtained from a total of 20,850 healthcare encounters, and 30.9% patients were aged ≤ 15 years. The most frequent conditions were gastrointestinal and respiratory diseases. Most frequent gastrointestinal symptoms were abdominal and gastric pain, nausea and vomiting, and diarrhea, suggesting that most patients suffered gastroenteritis. The predominance of cough, rhinitis, influenza-like illness, and sore throat among patients with respiratory symptoms suggests that most patients suffered from upper respiratory tract infections. Other frequent symptoms were headaches and pain in various organs. Three percentage of patients were considered to have malaria, 29.8% of patients were prescribed antibiotics and 2.6% antimalarial drugs, and 1.5% of patients were hospitalized. Only one death was recorded. Preparedness of the medical infrastructure should target these syndromic features, in terms of diagnostic tools and specific treatments, including pediatric formulations. It is also essential to improve the quality and rapid availability of data to enable real-time analysis of medical events at the GMT and to implement a rapid response, if necessary.

Pilot Survey of Knowledge, Attitudes and Perceptions of Hajj Deployed Health Care Workers on Antibiotics and Antibiotic Prescriptions for Upper Respiratory Tract Infections: Results from Two Hajj Seasons

Antimicrobial resistance (AMR) is a global public health issue. Upper respiratory tract infections (URTIs) are common illnesses during Hajj, for which antibiotics are often inappropriately prescribed. Hajj healthcare workers' (HCW) knowledge, attitudes and perceptions (KAP) about AMR and antibiotic use for URTIs are not known. We conducted a survey among HCWs during Hajj to explore their KAP regarding antibiotic use for URTIs in pilgrims. Electronic or paper-based surveys were distributed to HCWs during the Hajj in 2016 and 2017. A total of 85 respondents aged 25 to 63 (median 40) years completed the surveys. Most participants were male (78.8%) and were physicians by profession (95.3%). Around 85% and 19% of respondents claimed to have heard about AMR and antimicrobial stewardship programs, respectively, among whom most had obtained their knowledge during their qualification. Implementation of URTI treatment guidelines was very low. In conclusion, HCWs at Hajj have significant knowledge gaps regarding AMR, often do not use standard clinical criteria to diagnose URTIs and display a tendency to prescribe antibiotics for URTIs.

The dynamics and interactions of respiratory pathogen carriage among French pilgrims during the 2018 Hajj

We conducted this study to describe the dynamics of the acquisition of respiratory pathogens, their potential interactions and risk factors for possible lower respiratory tract infection symptoms (LRTI) among French pilgrims during the 2018 Hajj. Each participant underwent four successive systematic nasopharyngeal swabs before and during their stay in Saudi Arabia. Carriage of the main respiratory pathogens was assessed by PCR. 121 pilgrims were included and 93.4% reported respiratory symptoms during the study period. The acquisition of rhinovirus, coronaviruses and Staphylococcus aureus occurred soon after arrival in Saudi Arabia and rates decreased gradually after days 5 and 6. In contrast, Streptococcus pneumoniae and Klebsiella pneumoniae carriage increased progressively until the end of the stay in Saudi Arabia. Haemophilus influenzae and Moraxella catarrhalis carriage increased starting around days 12 and 13, following an initial clearance. Influenza viruses were rarely isolated. We observed an independent positive mutual association between S. aureus and rhinovirus carriage and between H. influenzae and M. catarrhalis carriage. Dual carriage of H. influenzae and M. catarrhalis was strongly associated with S. pneumoniae carriage (OR = 6.22). Finally, our model showed that M. catarrhalis carriage was negatively associated with K. pneumoniae carriage. Chronic respiratory disease was associated with symptoms of LRTI. K. pneumoniae, M. catarrhalis-S. aureus and H. influenzae-rhinovirus dual carriage was associated with LRTI symptoms. Our data suggest that RTIs at the Hajj are a result of complex interactions between a number of respiratory viruses and bacteria.