RE:RE:ANALYSIS OF SAUDI VAC RESULTSMikeyH wrote: This is a fair post, and I don't disagree with the theory. But the company will need a much larger study to prove it; 3/3 to claim a 100% sensitivity is statistically unacceptable in a clinical setting.
If the FDA award EUA on the back of this Saudi study, it will come with stringent user guidance (just like the Abbott test). I guess Sona will then go away and, in addition to trying to start selling the test as a standard symtomatic tool, attempt a larger study to prove true effectiveness in asymptomatic patients. This will be a lengthy and challenging clinical effort; as someone else mentioned recruiting enough individuals at the correct stage of infection is very time consuming.
The company needs to be very careful it doesn't fall between the cracks here. I absolutely agree with everyone that if the test picks up asymptomatic cases the opportunity is HUGE, but they will need to provide absolute clinical proof to the regulators. The specitivity data from the clinical study (90%) is also slightly concerning; a test of this sort should generally never return a false positive. 1/10 false positives isn't great.
I know many on here don't appreciate my posts, and to be honest I couldn't care less. My goal here is to provide scientific balance to the 'we're going to the moon' tools who are simply here to pump the stock. I want the test to succeed
MikeyH,
you make some valid points but I think that these can be addressed as follows:
1. "3/3 to claim sensitivity is statistically unacceptable." First all it was part of an overall study in which the overall Sensitivity was 84.6% which is within FDA Guidelines. Secondly there were only 3 Asymptomatic positives and they identified them all. It identified the only 3 positives out of a sample of 40 ,you can´t ask for more than that and it IS statistically acceptable (or significant as is the correct term).
2. " it will come with stringent user guidance ( just like the Abbott test)." The advice on the Abbott test is that Asymptomatic testing is not allowed because they have ZERO evidence on the Asymptomatic. They however are allowed to test on all Symptomatic patients, both Low Viral Load as well as High Viral Load, despite the fact that Low Viral Load patients formed only 17% of their Testing Population. In contrast Asymptomatic patients represented 40% of the Sona Test Population. If the FDA is consistent who is to say that they definately won´t allow an Asymptomatic Approval? Time will tell.
3. Not in this post but in a later one you continue to insist that the 96/96 Sensitivity and Specificity was from killed-virus In-House Sona studies when it has been clearly shown that MRI Global replicated these numbers on live virus cultures in their 3rd Party Validation. After this was proved you failed to respond but now come back with the same old false argument.
4. "Specificity is also slightly concerning .1/10 false positives isn´t great". OK, first of all the Specificity in the Asymtomatic group was 100% and that in a sample of 37 patients. That is Great and that is the group that we are most concerned about. Secondly all the false positives were in the group of patients who were hospitalised, for who knows how long, and where other complicating factors may be present eg. antibody and T-cell formation, medication, treatment drug reactions etc etc that may have played a part.
Thirdly Specificity is not nearly as important as Sensitivity in Screening. Take the following scenario: 400 passengers want to board a plane. It is likely that possibly up to 40 may be +ve, leaving 360 negatives. If we say that out of these 36 (10%) are false positives (although as I say I am sure that the figure will be much lower for the reasons above) that means you have 76 +ve tests which you repeat 15-20 minutes later. Out of the original 36 false positives only 3-4 will again be a false positive and will not be allowed to fly. That means that 3-4 people miss their flight unfairly. A small price to pay to allow 356 passengers to board the flight, and the same will be multiplied many times over at schools, workplaces etc. In any event I think that the 10% is very probably and that the prolonged hospitalisation of some patients has caused this misinterpretation. To get the world back on a normal footing we need to do lots of rapid and repeat Antigen testing and yes a few will be wrong but the repeat nature and the speed of the response of the testing will bring the Pandemic under control. It is now becoming generally accepted that this is the ONLY way forward nd it needs to be SOON.
5. You also forget that the FDA is not the only game in town. The Saudis clearly feel the evidence is there to use in their own Screening Programme and others will follow.