Covid Testing Quiz
Which group is currently subject to 3 PCR Covid tests each week?
- All healthcare workers
- Unvaccinated healthcare workers in nursing homes in New York
- Undergraduate students at one Ivy league college
The answer is C. In response to the report of the Nu Xi Omicron variant, Harvard University increased its Covid testing cadence of undergraduate students to three times a week. This measure was taken despite a 97% vaccination rate among Harvard students and employees. In addition, there is a mask mandate. Students must follow safe eating rules:
“Practice ‘Consume & Cover’ — Consume your meal and immediately mask up when done. Use the ‘Quick Sip Rule’ — When drinking, lower your mask, take a sip, and then promptly cover your mouth and nose. If you’re taking your time between bites and sips, put your mask back on.”
Harvard has access to some of the top public health minds, but the student health czar didn’t listen to Dr. Martin Kulldorff, a bio-statistician and Professor of Medicine at Harvard Medical School. He explained in his op-ed The Case Against Covid Tests for the Young and Healthy:
“Testing is intended to save lives, not to detect asymptomatic people who are otherwise healthy. The concept of a “school outbreak” is misleading, because it typically denotes a number of positive tests, not significant illnesses… [On the other hand] it is important to increase testing of hospital and nursing-home staff as well as visitors, so that family members can spend time with their older kin, for whom Covid-19 infection poses an unacceptable mortality risk.”
Instead of listening to a bio-statistician, Harvard took the advice of a doctor who fell asleep during the lecture on Bayes Theorem or just doesn’t comprehend it. Neglect of Bayes Theorem is understandable. I remember the day we had the lecture. Most of the class angrily revolted against the lecturer who tried to engage in an explanation of the probability of picking a certain color ball from a barrel given the previous results. It was just too mathematical and abstract. Bayes Theorem, however, produces important practical results. When doing a test on a group that has a very low likelihood of disease, a positive test is likely to be a false positive.
Applying this theorem to covid testing, we can calculate that 90% of Harvard’s positive covid tests are false positives. You can do the math yourself. First, from the test characteristics 80% sensitivity and 98.5% specificity, calculate the likelihood ratio of a positive test which comes out to 53. Then estimate the pre-test probability of disease using the prevalence in Cambridge (approximately 0.2%). Now, use Fagan’s nomogram to get the post-test probability of disease. Even if the prevalence actually was a very high 0.5%, the false positive rate would still be roughly 70%. Be that as it may, knowing they are false positive does little to console the students sent to Harvard’s Quarantine and Isolation archipelago.
Harvard is a bunch of morons and I don’t know why anyone would think otherwise.
I went to a good local college (then known as Illinois Benedictine College) and got into medical school from there. It’s now known as Benedictine University as they have some Phd programs now so they can be called a “University”.
Those were good years as there were a lot of us who wanted to get into dental and medical school. All of us got in as I was in the class of ’78 and it was getting hard to get into professional school at that time. Those of us who survived the academic program got in. It was a very dicey situation. Thank heavens for the University of Illinois at the time. They had the largest medical school class at the time and I was able to get in there. Got a great education from them too in Peoria, Illinois.
I just go out and put on a mask when I have to shop. My spouse passed in 2019 so I’m back to being a bachelor. I live in a rural area so yeah Covid is around, it kills people but my exposure is limited.
Best regards,
Allen Kurt Savegnago, M.D. (retired)
Canton, Illinois
Excellent post. I’ve always used a 2 x 2 table of 10000 sample population with truth versus test results instead of the nomogram, but the point is spot on.
I’m sure they’re putting those masks back on after every swig of beer at campus parties.