The causes on how they contacted the TB have not been determined but likely, and must be due to some contact with the TB patients. All have been reported to have no direct contact with the 6. Then how could they possibly get into close contact or proximity with the 6? One likely possibility must be the lifts, in instances when one of the 6 was using the lift and the unaware went in after them.
The other higher possibility areas must be the trains or the offices they were working in. But these are unlikely the case for those screened positive in this exercise. But this does not rule out the 2 positive cases spreading in the trains or in their offices, or the 6 that may have travelled in trains and their work areas.
So far never heard of screenings in the work areas of the affected TB patients. It is almost impossible to screen commuters who happened to take the same trains. Would the Ministry attempt to screen those working in the same offices, using the same toilet cubicles or pantry?
This is not the end of the Ang Mo Kio cluster and the people that may be affected or infected through other means of contact could be out there. We are so lucky that there is no widespread of TB in the island when the jam packed trains are so conducive contraptions for the spread of communicable diseases like TB and what else.