CDC does not recommend serologic testing for measles, mumps or rubella for employees with two
documented doses of MMR vaccine (past or present). If such employees are inadvertently tested and found to be measles IgG negative or equivocal, CDC recommends
trusting the vaccine history rather than the serologic results, and considering such employees presumptively immune to measles. See:
https://www.cdc.gov/mmwr/preview/mmwrhtml/rr6204a1.htm.
What is important to know, and I don't think is well known, is that commercial measles IgG testing is often not sensitive enough to identify people who would mount an adequate immune response to measles
if they were exposed.
In California, if a HCW (or any other person) is exposed to measles and it is likely that they have received MMR vaccine but they are measles IgG negative or equivocal at a commercial lab, we ask that the blood specimen be sent for retesting at
our state laboratory where it is almost always IgG positive.
If a HCW is actually exposed to measles, we do not consider birth before 1957 adequate proof of immunity, and would want such HCWs tested for measles IgG. Similarly, we would want to retest exposed HCWs with a history of being measles IgG
negative or equivocal after a history of two doses of MMR vaccine. If either category of HCW was then tested at a commercial lab and found to be measles IgG negative or equivocal, we would request retesting at our state lab to determine their true measles
immune status.
In our experience, falsely measles IgG negative or equivocal results are not uncommon, and we don't want to furlough or quarantine people unnecessarily.
Kathleen Harriman
California Department of Public Health
Richmond CA
Today's Topics:
- Measles Prevention in Non-immune Appropriately Vaccinated Healthcare Employees (Leibu, Rachel)
- Re: Measles Prevention in Non-immune Appropriately Vaccinated Healthcare Employees (Lawrence Budnick)
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Message: 1
Date: Mon, 6 May 2019 01:28:20 +0000
Subject: [MCOH-EH] Measles Prevention in Non-immune Appropriately Vaccinated Healthcare Employees
HI Everyone,
With the ever growing measles outbreak, how are you handling those employees who have appropriate proof of vaccination for measles but have a negative measles titer post vaccination. What are you doing for this cohort of employees both prophylactically
and in the event of an actual measles exposure?
Rachel Leibu, MD, MBA, MS, FACOEM
Medical Director Occupational Medicine Services Atlantic Health System
973-829-4277
Message: 2
Date: Mon, 6 May 2019 12:37:08 +0000
Subject: Re: [MCOH-EH] Measles Prevention in Non-immune Appropriately Vaccinated Healthcare Employees
Attached is the guidance document from our state health department. Based on it and measles exposure incidents on our campus in 2013 and 2014, we would give a third dose of vaccine and retiter in 6-8 weeks, to help guide future potential exposures. It
is possible that the negative titer the person had was taken long after the 2nd measles vaccination. In addition, as the state guidance notes several times, "Extra doses of MMR are not harmful" as long as there are no contraindications.
Lawrence D. Budnick, MD, MPH
Professor of Medicine
Director, Occupational Medicine Service
Rutgers University - New Jersey Medical School