[MCOH-EH] TB Exposures - AOHC

[Philip Harber]

Another perspective on the "10 minute exposure":

In many situations, the "exposure time" is significantly greater than the
time in which the patient and the HCP are in close physical contact. Even
after the patient is removed from the room, the air contains many aerosol
particles that will remain airborne for significant time. Therefore, if the
x-ray technician remains in the room after the patient left, the technician
will be breathing significantly contaminated air. (Indeed, the risk may be
greater not just because the duration of exposure is so much greater, but
because the suspended particles desiccate and therefore become smaller in
size and more likely to be inhaled and bypass upper airway clearance
mechanisms).

Practical consideration: The room with a highly infectious patient should
not be used for sufficient time to allow particulate clearance. This
depends upon filter efficiency and the ACH rate. (This was commonly
implemented during the peak COVID era).

Dictated to Dragon voice dictation system. I apologize for any overlooked
errors.

phil

Adjunct Prof., Public Health
Adjunct Research Prof., School of Landscape Architecture
University of Arizona
Prof. Emeritus, UCLA

*Philip Harber *

email:  philharber at gmail.com or pharber at arizona.edu
<pharber at email.arizona.edu>

----------------------------------



On Wed, Sep 17, 2025 at 5:00 PM Thanassi, Wendy via MCOH-EH <
mcoh-eh at mylist.net> wrote:

> Hello!
>
>
>
> Thanks for bringing this up, Mary! One of our MCOH members’ hospital
> actually had this case, which I was happy to present. That smear-positive
> patient was up-close and personal with an unmasked radiology team member
> getting the patient situated for the exam.
>
>
>
> Expsosure, as we talked about, deserves its own scoring list. ((all about
> the source, all about the disease, all about the contact)… lots of details
> that can make each exposure different.
>
>
>
> So, at AOHC in Chicago next year, Krithi has a session just on TB exposure
> investigations proposed. In my dream world, we’d build a scoring system to
> help decide who to test and who not. In general, do concentric circles of
> the most exposed first. And use the chart to see who really spent time with
> the patient rather than just “drive-bys.”
>
>
>
> 😊
>
> Happy weekend,
>
> Wendy
>
>
>
> *From:* MCOH-EH <mcoh-eh-bounces at mylist.net> *On Behalf Of *Giovannetti,
> Mary
> *Sent:* Tuesday, September 9, 2025 5:26 AM
> *To:* mcoh-eh at mylist.net
> *Subject:* [EXTERNAL] [MCOH-EH] TB Exposures
>
>
>
> Good morning,
>
> Dr. Thannasi delivered an excellent presentation on TB exposures last
> week. During the session, we discussed a case involving someone who
> converted after just a 10-minute unprotected exposure to a smear-positive
> patient. This has prompted me to revisit our current policy regarding
> post-exposure testing and the amount of time exposed.
>
>
>
> I’d appreciate learning more about your current guidelines:
>
>    - How do you determine the threshold for TB exposure duration?
>    - When do you initiate testing following an unprotected exposure?
>
>
>
>
>
>
>
>
>
> *Mary C Giovannetti, DNP, APRN, FNP*
>
> Director/Nurse Practitioner| Employee Health
>
> Physician's Center, -100 East Wood St., Suite 204 | Spartanburg, SC 29303
>
> o: 864-560-6514 c: 864-497-4087 | f: 864-560-6509
>
> e: mgiovannetti at srhs.com | w: SpartanburgRegional.com
> <http://www.spartanburgregional.com/>
>
>
>
> Have you scheduled your annual assessment in Readyset?
>
> Go to Hub, Applications, MyHealth ReadySet
>
>
>
>
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