(09-02-2020, 12:00 AM)magnus Wrote: So says a study from Iceland
https://www.nejm.org/doi/full/10.1056/NEJMoa2026116
I'm not fully comprehending the information at this time of day but perhaps others here would find the study interesting.
Ah, something about the COVID-19 disease rather than the effect on sports or politics or economy! It's been a while on this board.
Actually, they say that some levels were stable and some weren't:
Quote:Antibody levels measured with both pan-Ig antibody assays increased over the first 2 months after qPCR diagnosis and remained at a plateau over the next 2 months of the study. IgM anti-N antibody levels increased rapidly soon after diagnosis and then fell rapidly and were generally not detected after 2 months. IgA anti-S1 antibodies decreased 1 month after diagnosis and remained detectable thereafter. IgG anti-N and anti-S1 antibody levels increased during the first 6 weeks after diagnosis and then decreased slightly.
Some things that I found interesting:
Quote:Of the preexisting conditions, and after adjustment for multiple testing, we found that body-mass index, smoking status, and use of antiinflammatory medication were associated with SARS-CoV-2 antibody levels. Body-mass index correlated positively with antibody levels; smokers and users of antiinflammatory medication had lower antibody levels. With respect to clinical characteristics, antibody levels were most strongly associated with hospitalization and clinical severity, followed by clinical symptoms such as fever, maximum temperature reading, cough, and loss of appetite. Severity of these individual symptoms, with the exception of loss of energy, was associated with higher antibody levels.
Quote:By April 30, a total of 20,766 Icelanders had been placed in quarantine. Of the 1797 Icelanders who tested positive by qPCR, 1088 (61%) were in quarantine when tested. Despite substantial qPCR testing of persons in quarantine, 2.3% of persons in quarantine who did not receive qPCR-positive result (i.e., a diagnosis of infection) developed SARS-CoV-2 antibodies. Household exposure was more likely to lead to infection than other types of exposure, which suggests that people who share a household with an infected person should not have contact during quarantine and that contacts of household members should be quarantined.
(Italics mine)
61%... In Santa Clara County, tracing is still only reporting about 1/3 of the cases related to other cases. I continue to be astonished by that number, considering the (presumed) likelihood of infection within a household.
They hint that 19 of the qPCR-positive individuals that tested negative for antibodies twice (multiple assays each time) may have had a false positive on their qPCR. They had 2102 samples and 1237 people, so at most 865 had two samples. So, 19/865 qPCR positives might have been false. There were 1797 recovered cases, so one could estimate 19 * 1797/865 = 39.4 total false positives. Out of 54,436 people tested. 54436 - 1797 = 52,639 (approx true) negatives. 39.4/52639 = 0.075% FP rate
