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@gmail.com or pharber@arizona.edu 


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



On Wed, Sep 17, 2025 at 5:00 PM Thanassi, Wendy via MCOH-EH <mcoh-eh@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@mylist.net> On Behalf Of Giovannetti, Mary
Sent: Tuesday, September 9, 2025 5:26 AM
To: mcoh-eh@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@srhs.com | w: SpartanburgRegional.com

 

Have you scheduled your annual assessment in Readyset? 

Go to Hub, Applications, MyHealth ReadySet   

 

 

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