@augieray

I was contacted by the local health authorities in Luxembourg after presumed exposure to a case of open tuberculosis on a long haul flight between Bangkok and Paris.

I was twice tested at a 6-month interval and both sets of tests came back negative.

The infected passenger was I believe roughly three meters from where I was seated as there was a woman having repeated coughing fits throughout the entire duration of the flight seated at about that distance from me.

Although the pathogen in the case of TB, Mycobacterium tuberculosis, is orders of magnitude larger than any virus, Covid is spread not by individual viruses floating in the atmosphere but by droplets of body fluids containing a viral load, so I guess the two are comparable.

Apparently, the infected passenger collapsed on arrival at the airport in Paris, was taken to hospital and she was diagnosed with active tuberculosis, hence the medical alert being raised with other passengers.

Initial screening with a Montoux test was violently positive, which scared the life out of me as multi-antibiotic resistant TB is becoming commoner and commoner. Thankfully, they then performed a much more sensitive and discerning test, Quantiferon Gold, that came back totally negative as did a second similar test six months later.

I asked the consultant supervising my case why the original Mantoux Test would have come back so violently positive when the more sensitive tests came back negative and he suggested that I must still have antibodies from my original BCG Vaccine given when I was a teenager about 50 years earlier which can trigger a reaction to a Mantoux test but will not impact the result of a Quantiferon Gold test. He went on to say although it's unusual to retain immunity from the BCG Vaccination for that period of time, it is not unheard of.