key: cord-0871523-xw1pes2u authors: Barasheed, Osamah; Alfelali, Mohammad; Tashani, Mohamed; Azeem, Mohammad; Bokhary, Hamid; El Bashir, Haitham; Rashid, Harunor; Booy, Robert title: No evidence of MERS‐CoV in Ghanaian Hajj pilgrims: cautious interpretation is needed date: 2015-04-14 journal: Trop Med Int Health DOI: 10.1111/tmi.12513 sha: 38ca1193d5cae70c2d050255e0daf0ba31430192 doc_id: 871523 cord_uid: xw1pes2u nan The study by Annan et al. recently published in the Tropical Medicine and International Health is, to our knowledge, the first attempt to describe the epidemiology of respiratory infections including Middle East respiratory syndrome coronavirus (MERS-CoV) among African Hajj pilgrims [1] . The study sample was representative of the Ghanaian Muslim population. However, there are limitations to the interpretation of their findings. Intense crowding, close contact and shared accommodation amplify the risk of transmission of respiratory infections among Hajj pilgrims [2] . Emergence of MERS-CoV during 2012 in Saudi Arabia and neighbouring countries has raised concern about the risk of global spread of MERS-CoV from Hajj [3] . In 2013, the virus spread to a number of countries, including by Umrah performers/returnees [4, 5] . There were several surveillance studies performed at Hajj 2013, referenced by Annan et al., but others not been cited even though they add to our understanding [6, 7] (Table 1) . Studies conducted at Hajj 2013 varied in their methods, study population and sample size, perhaps influencing outcomes. Memish et al. [8] and Annan et al. [1] recruited, respectively, 5235 and 839 people but provided only airport-based surveillance data. In contrast, studies by Barasheed et al. [7] and Benkouiten et al. [6] were conducted at the main Hajj locations (Makkah and Mina) during the peak period of Hajj with daily follow-up. Benkouiten et al. followed one Hajj travel group (n = 129) from Marseille, France, and studied an array of microorganisms including bacteria and uncommon viruses, whereas Barasheed et al. selected participants from several travel groups who developed respiratory symptoms; they were closely followed up in a large trial (n = 1038) involving Saudi Arabian, Australian and Qatari pilgrims. All these 2013 studies involved testing nasopharyngeal or nasal samples for MERS-CoV (Benkouiten et al. additionally obtained throat swabs), which are less sensitive in detecting MERS-CoV (Table 1) ; lower respiratory tract samples such as bronchoalveolar lavage and tracheal aspirates result in higher yields [9] ; therefore, Annan et al.'s notion that there is 'no evidence of MERS-CoV in Hajj pilgrims returning to Ghana, 2013' sounds overenthusiastic [1] . Most studies reported participants' respiratory symptoms; the most commonly reported symptoms were cough, sore throat and fever. Barasheed et al. [7] and Benkouiten et al. [6] reported the prevalence of influenzalike illness (ILI) among their participants to be 11% and 47%, respectively, but Annan et al. [1] did not provide the prevalence of ILI. One caveat is that the definition of ILI differed between the studies ( [12] . By contrast, during the subsequent Hajj season, the attack rate of RSV was very low (0.7%) among UK pilgrims and zero among Saudi pilgrims [13] indicating that the circulation of RSV is dependent on various factors such as seasonality, geographical original of the pilgrims and their close association with children. Absence of MERS-CoV in nasal or nasopharyngeal samples of pilgrims does not rule out risk of the disease at Hajj. A recent estimate suggests that MERS-CoV has a basic reproduction number (R0) similar to that of SARS, that is 2-6.7 [14] , but mathematical modelling studies indicate that the risk of an outbreak is low [15] . Considering the increasing number of Umrah pilgrims in the forthcoming months when the likelihood of a MERS-CoV upsurge is high due to the seasonal pattern of the disease [16] , surveillance must continue. Accordingly, we continued our study in 2014 and recruited over 2000 pilgrims from Gulf countries and Australia. Preliminary findings suggest that of 298 Australian pilgrims, only two (0.7%) had symptoms of severe respiratory infection, but none had pneumonia. Virological testing will provide further data on the epidemiology of respiratory viruses among Hajj pilgrims. Ongoing active surveillance is mandatory to better understand transmission dynamics of MERS-CoV. High prevalence of common respiratory viruses and no evidence of Middle East Respiratory Syndrome Coronavirus in Hajj pilgrims returning to Ghana Prevention of influenza at Hajj: applications for mass gatherings Emerging respiratory viral infections: MERS-CoV and influenza Has Hajj-associated Middle East Respiratory Syndrome Coronavirus transmission occurred? The case for effective post-Hajj surveillance for infection Middle East respiratory syndrome coronavirus (MERS-CoV): prevention in travelers Respiratory viruses and bacteria among pilgrims during the Viral respiratory infections among Hajj pilgrims in 2013 Prevalence of MERS-CoV nasal carriage and compliance with the Saudi health recommendations among pilgrims attending the Respiratory tract samples, viral load, and genome fraction yield in patients with Middle East respiratory syndrome From the Hajj: it's the flu, idiot Influenza and RSV among returning travellers Influenza and respiratory syncytial virus infections in British Hajj pilgrims Viral respiratory infections at the Hajj: comparison between UK and Saudi pilgrims Estimation of MERS-coronavirus reproductive number and case fatality rate for the Spring 2014 Saudi Arabia outbreak: insights from publicly available data Estimating potential incidence of MERS-CoV associated with Hajj Pilgrims to Saudi Arabia The pattern of Middle East respiratory syndrome coronavirus in Saudi Arabia: a descriptive epidemiological analysis of data from the Saudi Ministry of Health The study conducted by our team [7] was made possible by a National Priorities Research Program grant from the Qatar National Research Fund (a member of Qatar Foundation).