Media and Ministry reports are filtering in from many different countries that their Hajj pilgrims have been safely returning from their pilgrimage.
To date there have been no reports of Middle East respiratory syndrome (MERS) disease in any pilgrim.
I presume this is all observational diagnosis? It would be very interesting to read whether any actual laboratory testing is occurring in any of these States. If it is, are the pilgrims PCR-negative?
What observation alone cannot tell us is whether a pilgrim infected but not showing signs.
Self-reporting of mild disease without overt signs, can be problematic and may bias away from capturing all cases in the absence of laboratory testing. If cases do enter a State "under the radar" they may still shed virus to others in their new locale. Some of those others may be older males with comorbidities; the MERS coronavirus's (MERS-CoV) highest impact population.
Of course we don't really know if mild and asymptomatic cases can transmit effectively. We might if there was more widespread testing. Since we haven't seen that level of testing coming from the site of most MERS-CoV infections, the Kingdom of Saudi Arabia, perhaps there is an opportunity for other States to step up and test not just returning pilgrims but their families and other contacts and see whether their upper respiratory tract's are free of MERS-CoV RNA?
These media reports also don't tell us what definitions are used by each State to define a pilgrim as being free of MERS-free. It may be the absence of any sign of any respiratory disease, or it be just absence of severe signs and symptoms, or perhaps a combination of signs and symptoms e.g. fever+cough or cough+difficulty breathing.
Too many knowledge gaps.