1/ The major #covid19 outbreak from @BrighamWomens where I work is now published in @AnnalsofIM — definitely worth a read. Phenomenally detailed work here from many smart people.

The index patient tested negative twice, but soon became positive after.
https://www.acpjournals.org/doi/full/10.7326/M20-7567

2/ “The virus was likely introduced into the facility by a symptomatic patient who tested negative twice on admission but in retrospect was contagious from at least hospital day 3 and infected staff and patients for at least a week before detection” #covid19

3/ The infection control team & overall program at our hospital is awesome. They are among the smartest people I know. And despite all of the protective measures in place, transmission & a serious #covid19 cluster still happened.

4/ Among staff cases that responded re their use of personal protective equipment, 23/23 responded that they wore surgical masks at all times; 0/23 reported wearing N95 at all times.

5/ Why? Because we have a universal masking policy for surgical masks + eye protection. And we only wear N95 masks if the patient is on enhanced respiratory precautions. The index case, after two neg tests, despite ongoing symptoms, was removed from these precautions. #covid19

6/ We have had subsequent outbreaks even after this, albeit smaller; it was one of the main reasons why I chose to wear N95s in almost all patient rooms for a time- and had the rest of our medicine team also do that back in December. It’s easy to do- low hanging fruit here.

7/ The authors note that while it was hard to always isolate the circumstances of transmission, there were two definitive cases infected from the patient while wearing surgical masks and eye protection

Read this section. The patient was masked whole time in one, partly in other

8/ So here we now have a case of #covid19 transmission between patient & staff despite both wearing surgical masks; and the staff also wearing eye protection. And as the authors point out, it is exceedingly difficult to isolate this bc usually have many confounding contacts

9/ Now look at the recommendations section.

Surgical masks & eye protection may not provide adequate protection during close encounters esp if patient cannot wear a mask.

Many patients we care for cannot/do not consistently wear masks- if you’ve been on the wards you know this.

10/ I understand that if all parties are wearing surgical masks - which remember are still 3 layers w/ a meltblown layer similar to N95 (cc @larmbrust) that transmission is less likely (although still happened even here).

Now imagine

11/ This is a big reason why we been pushing for #BetterMasks — even if these don’t end up being N95s or equivalents although that would be *ideal* for all indoor poorly ventilated crowding where not everyone has a mask on

Those who want better protection deserve access to it

12/ & even before this cluster was published- why have we been pushing for enhanced personal protection despite limited evidence? Bc it’s another low hanging layer of protection that should be easy to achieve at scale, & evidence generation takes valuable time that we don’t have

13/ Conflating the absence of evidence w/ the evidence of absence is a mistake made early on when some said we don’t need community level masking at all bc we lacked definitive data one way or the other. Let’s not do the same w/ #BetterMasks

14/ We know in laboratory settings that better fitted, better filtering masks do better than regular cloth masks. We are in the process of generating more real world data (here it was surgical masks- if N95s were used consistently, could this outbreak have been prevented?)

15/ & we know in the real world, it’s rare that all parties are consistently wearing any type of masks throughout all encounters all the time. Depending on where in the country you live, it’s increasingly unlikely. We need more people to wear any mask + better masks too #covid19