Mortality? Maybe I did the math wrong, but it seems that using the description of hits taken from the disease, there's no way a PC can die from it. ...
DA1, Annic Nova: "If the number on the table is rolled or exceeded, the individual has contracted the disease. Immediately roll two dice and subtract the skill level of any attending medic (one medic may attend up to four persons). That number is the immediate damage inflicted. If it exceeds 8, roll again as before, and inflict that number of hits. Continue until the result is less than 8."
Not calculating for age or other variables, health (# hits to kill) of the basic Traveller population, based on sum of three rolls of 2d6, ranges from lowest of 6 (exceedingly frail) to highest of 36, with average of 21; 88% of the population falls between 15 and 27. Higher or lower is possible due to aging, career effects, etc., but that's a fair starting point.
Recalculating ...
Based on a 2d6 damage roll, roll again if 9+, roll again if that roll is 9+, and so forth ...
26/36 chance of getting 8 or less damage. Death occurs to a handful of extremely weak individuals on one roll: 0.03% of the total population die (a bit under half of those feeble folk) at 8 or less, another 0.15% die at 9+ but before you need to bother with rolling that second roll.
10/36 chance of needing to make a second roll (assuming one survived the first). 26/36 chance of getting 8 or less
on that second roll, 10/36 chance of getting 9+ (and therefore needing a third roll). Range of damage 11 to 24. 12.3% of the population dies on that second roll.
7.7% (10/36*10/36) chance of needing to make three rolls. At that point, calculating it gets seriously complicated, but only a small percentage of the population (7.7%) get to that point; however, you've already taken from 18 to 24 hits at that point, and only 12% of the overall population has a health better than 27. The absolute least damage that you will take from that third roll is another 2. Unless you're very hardy, there's a good chance that third roll will kill you if you've gotten that far.
Overall, of those who became infected 72% recovered after the first roll, another 8% recovered after that second roll, 12.49% are dead after two rolls, and 7.51% are heading into a third roll and at serious risk of death, though some will survive. Maybe the total death rate ticks up another three or four percent - 15 or 16 percent.
That's not figuring for career boosts or aging losses. Traveller has anagathics, but only a relatively tiny fraction of the total population have access and can afford them. At any rate, elderly tend to be a small fraction of the overall population. Not everyone gets a career boost to stats, but figure the overall population will be slightly healthier than average as a result, so that 15 to 16 percent comes down a wee bit. Hard to calculate that, though - figuring what percentage of the population gets lucky with a stat gain or two over their various careers is a bit beyond me.
Then there's the medical community: you subtract the skill of your attending. Not everyone will have access to medics - poor folk may not be able to afford one (they always suffer disproportionately in these events), and some communities may be a little lean on medical staff, but most folk will have access to a Medic 1, a lot of them will have access to a Medic 2, a fair portion will have access to a Medic 3. I get a 9.36% death rate with a Medic-1 attending, a 6.75% death rate with a Medic-2 attending, a 4.69% death rate with a Medic-3 attending - and that's for the two rolls; figure the effects of third roll in and they all go up.
Bottom line is: given all the possible variables involved, I'm comfortable with a rough estimate of 7% mortality, though I'm more than willing to quibble it down to 5% or 6%. As is common in such events, the axe falls hardest on the poor and the weak, and especially hard on the kiddies.
Add: by modern standards, this would be considered a rather vicious disease, killing 15 thousand of every million population.