Healthline: What we know about breakthrough monkeypox cases
UC expert says people with certain medical conditions may be less likely to be protected
The World Health Organization announced recently that breakthrough infections have been reported in people who had been vaccinated against monkeypox. Healthline reported there is limited data available on the efficacy of the JYNNEOS shot, so it will take time to understand how effective it is at preventing infection. Data from the 1980s has shown that the vaccine was at least 85% effective, however, some health experts expect that number to change in the current outbreak. One of the experts cited in the Healthline story was Carl Fichtenbaum, MD, of the Division of Infectious Diseases at the UC College of Medicine.
Carl Fichtenbaum, MD, of the Division of Infectious Diseases at the UC College of Medicine/Photo/Joe Fuqua II/UC Marketing + Brand
Fichtenbaum says that the vaccine has not been tested in humans to a large extent, so 85% is really a ballpark estimate.
Healthline reported the strength of people’s immune systems varies and certain individuals may not mount a strong enough immune response to avoid getting sick even if they are fully immunized.
“As always, those with immunosuppression, cancer, transplant patients, and persons with HIV who have a lower CD4+ lymphocyte count below 350 cells/mm3 would be more likely to not respond as well to vaccine and have a breakthrough infection,” Fichtenbaum said.
People older than 60 are also likely to be less protected, Fichtenbaum added.
Fichtenbaum says we are still learning about how common breakthrough infections are, and we don’t have the best track record for preventing the spread of infectious diseases during public health emergencies.
“Time will tell how many breakthroughs occur,” Fichtenbaum said.
Next Lives Here
The University of Cincinnati is classified as a Research 1 institution by the Carnegie Commission and is ranked in the National Science Foundation's Top-35 public research universities. UC's graduate students and faculty investigate problems and innovate solutions with real-world impact. Next Lives Here.
Related Stories
‘Designer drug’ shows early neuroprotective signal in acute ischemic stroke
October 28, 2025
Medscape highlighted new trial results led by the University of Cincinnati's Eva Mistry that found an experimental drug shows promise in protecting injured brain cells for patients with acute ischemic stroke.
Is menstrual fluid ‘the most overlooked opportunity’ in women’s health?
October 27, 2025
The Guardian recently reported that period blood has long been thought of as ‘stinky and useless’, but startups are exploring using the fluid to test for a wide range of health conditions — including endometriosis.
What is squalane, and how does it work to moisturize skin?
October 27, 2025
The University of Cincinnati's Kelly Dobos was featured in a Women's Health article discussing squalane, an ingredient being increasingly used in moisturizing skincare products.