9 ms·

Sorry, but this doesn't sound like "no strong evidence": Without adjustments for other variables, the two intervention groups had about a 10% reduction in over

by llukas 6y ago

Sorry, but this doesn't sound like "no strong evidence": Without adjustments for other variables, the two intervention groups had about a 10% reduction in overall ILI incidence over the 6 weeks compared with the control group, but this was not statistically significant. However, when the researchers analyzed the ILI rates for each week of the study and adjusted for other variables (age, sex, ethnicity, baseline hand washing practices, sleep quality, alcohol use, flu vaccination), they found that the FMHH group had significantly lower rates than the controls in weeks 4, 5, and 6 (35%, 44%, and 51%, respectively). The adjusted rates for the mask-only group also were lower than those of the control group in weeks 4, 5, and 6, with reductions ranging from 28% to 42%, but this did not meet the authors' significance criterion of P<.025. The authors say several factors may explain why a significant reduction in ILI was found only during the second half of the intervention period. One is that recruitment of students continued through the first 2 weeks of the intervention, increasing the sample size by 11%. Also, the proportion of FMHH participants who wore their masks more than the average 3.5 hours a day increased in the later weeks of the study, and confirmed flu cases on campus peaked in weeks 4 and 5.

marcell 6y ago
Well, it depends on what you think is "strong" evidence. A 10% reduction doesn't seem very compelling, and when you introduce the more advanced statistical analysis, that hurts the case in my eyes. There are probably less disruptive ways to get a 10% reduction. I found that study from this meta study here: https://pubmed.ncbi.nlm.nih.gov/20092668/ https://pubmed.ncbi.nlm.nih.gov/20092668/ which reviews a lot of these studies for influenza. Note, however, that most of the studies only look at if the masks protect the individual, not whether masks stop the spread of influenza, but the evidence seems pretty inconclusive.
- llukas 6y ago
  I agree that 10% reduction is not much in normal situation but not when ICU are at capacity or economy is shut down. Results from weeks 4, 5 and 6 are interesting. Another study could see if this can be reproduced.

by llukas 6y ago

marcell 6y ago

Well, it depends on what you think is "strong" evidence. A 10% reduction doesn't seem very compelling, and when you introduce the more advanced statistical analysis, that hurts the case in my eyes. There are probably less disruptive ways to get a 10% reduction. I found that study from this meta study here: https://pubmed.ncbi.nlm.nih.gov/20092668/ https://pubmed.ncbi.nlm.nih.gov/20092668/ which reviews a lot of these studies for influenza. Note, however, that most of the studies only look at if the masks protect the individual, not whether masks stop the spread of influenza, but the evidence seems pretty inconclusive.

llukas 6y ago
I agree that 10% reduction is not much in normal situation but not when ICU are at capacity or economy is shut down. Results from weeks 4, 5 and 6 are interesting. Another study could see if this can be reproduced.