The Department of Health has gotten snippy with Scott Johnson at the Powerline Blog in answering his questions. In the most recent round they basically gave non-answers except to a question about the distribution of PCR test results at the state lab. Results from the last 3 months (why not the whole epidemic, something fishy right there) indicate that out of over 2200 tests 59.5% had a cycle number of 25 or less, so pretty clearly positives (meaning reflecting presence of actual viable virus), 29.4% were a cycle number between 26 and 35, so a mix of very likely positives, ambiguous results and very likely not true positives, and 11.1% were cycle numbers over 35, very unlikely to be true positives.
Now, that wasn’t so hard to share, was it? Unfortunately, you can see that the state lab ran an incredibly small percentage of tests over the last 3 months. The answer said the tests done there are largely for long-term care outbreaks, a population which one would suspect is more likely to have high viral loads. Across a more representative population, the distribution would almost certainly be much more heavily weighted to high cycle number positives. The state lab doesn’t have the incentive that hospital labs do to call every possible test positive so they get more revenue. So it is almost certain that other labs are running even a greater percentage of non-positive positives. But just based on what we are told, I would estimate that 20% of the positives represent non-viable positives, i.e., people who aren’t infectious, maybe aren’t even infected. If it is 20% in the state lab, I would risk a bet that it is at least 30% in the non-state ones. Wonder why DOH doesn’t do an actual study?
Then, of course, we get a couple of paragraphs of gibberish about why we shouldn’t pay too much attention to cycle number. If not, why is the state using it for defining a positive test. Once again, we see pure incompetence and ignorance of the current research, as they say: “Ct values aren’t a direct indicator of more virus (how sick someone is). There are so many variables to why a Ct value is what it is that a physician can’t make a clinical decision on it.” I have lost track of how many studies I have posted on which show a very direct correlation between cycle number and amount of virus and that very specifically recommend that physicians be given Ct numbers because they have clinical utility.
Someone who helps me regularly with data analysis and who was getting fairly regular answers to questions from DOH also was recently told that such help would no longer be available, that DOH didn’t have time for it. They are clearly shutting down and trying to control the messages even more tightly.