A quick note on masks and CDC guidance...
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Masks
A post or two ago I mentioned a meta-analysis about masks and forgot to include a hyperlink to the study. I know many of you are looking for it, so here it is. In short, the authors pooled 72 studies to assess how different public health mitigation measures (like masks, socially distancing, handwashing, etc.) impacted COVID19 infection. They found that some public health measures don’t really work. But, mask wearing reduced COVID19 infection by 53%. (For the record, this isn’t the only publication that shows masks work. For example, here are three studies that show they work well in schools.)
Mask effectiveness is certainly dependent on the type of mask, though. This is why a layered approach (vaccine, mask, ventilation, testing) is crucial, especially in light of Omicron. The Wall Street Journal published a great graphic earlier this week comparing the protection of different types of masks:
For those of you looking for masks, I’m a big fan of Aaron Collins who calls himself the “Mask Nerd”. He is mechanical engineer with a background in aerosol science. Since the beginning of the pandemic he has been testing, documenting, and reviewing the best masks he could find (in his free time). He has a YouTube channel and an incredible database. I will say, though, the adult database is overwhelming. The kids database is much better. His video on masks for kids under 12 was fantastic, too.
CDC guidance
The CDC guidance for isolation is beyond confusing. And I’m incredibly disappointed in their lack (or complete disregard) of scientific communication. I was going to put together a flow chart about what the guidance actually says. But, I found that the Maine CDC put together a fantastic one already:
Here is what you need to do if you’re in close contact of someone who has tested positive for COVID19:
Here is what you need to do if you test positive for COVID19:
I hope these evidence-based tools are helpful for making decisions in this ever evolving and confusing landscape we are forced to navigate.
Love, YLE
“Your Local Epidemiologist (YLE)” is written by Dr. Katelyn Jetelina, MPH PhD— an epidemiologist, biostatistician, professor, researcher, wife, and mom of two little girls. During the day she has a research lab and teaches graduate-level courses, but at night she writes this newsletter. Her main goal is to “translate” the ever-evolving public health science so that people will be well-equipped to make evidence-based decisions. This newsletter is free thanks to the generous support of fellow YLE community members. To support the effort, please subscribe here:
Katelyn, I may be late to the party on this one but did not see other comments about an omission in the Maine algorithm on positive tests. After a positive test, the next block should addressing "resetting the clock" if a positive test came first and symptoms developed in the subsequent 5 days. Otherwise, it is very well done and clearly shows why "testing out" at Day 5 is unnecessary in most cases.
For the mask chart - what are the parameters of people's exposure with these varying levels of protection? For example, are they indoors? Well ventilated, or not? How far apart are they from each other? I'm hoping to understand the context better, because this chart fuels either "everyone needs K/N 95" or "masks don't work".