Re: “Validating Tools to Detect and Inactivate Monkeypox Virus in Human Milk” by Clark et al.

Dear Editor:

We would like to share an idea on the publication “Validating Tools to Detect and Inactivate Monkeypox Virus in Human Milk. ¹ ” The purpose of this investigation was to see whether monkeypox virus (MPXV) was present in human milk (HM) and whether normal Holder pasteurization could inactivate the virus. The researchers used quantitative polymerase chain reaction to examine HM samples containing heat-inactivated MPXV. They also subjected HM samples containing infected MPXV to various settings such as freeze–thaw, room temperature incubation, and Holder pasteurization.

The findings demonstrated that both research and clinical nucleic acid tests could detect MPXV in HM, but with lower sensitivity than samples in viral transport medium. MPXV introduced to HM remained infectious after a freeze–thaw cycle or 1 hour of room temperature storage. Holder pasteurization, on the other hand, effectively reduced the infectious virus to undetectable levels, showing a considerable decrease in viral titer.

One potential weakness in the study could be the use of only one cycle of freeze–thaw or 1 hour of room temperature storage to determine the virus's stability in HM. These circumstances may not fully match real-world scenarios in which HM may go through several freeze–thaw cycles or be stored for prolonged periods of time at different temperatures. These circumstances may not correctly reflect viral breakdown or inactivation in HM, limiting the generalizability of the results. In addition, additional control groups and temperature and storage period adjustments might be advantageous to provide a more comprehensive understanding of the virus's stability in HM. Quality control is a basic rule for any test on milk samples. ²