Pasteurising breast milk at 63 degrees Celsius for about half-an-hour can inactivate the novel coronavirus SARS-CoV-2 — the virus that causes COVID-19 — researchers have found. The finding reaffirms that milk banks across the world, which provide donor human milk to vulnerable infants at the risk of a potential vertical transmission of the virus, are following a safe process.
The study was recently published in the Journal of Paediatrics and Child Health. It was a partnership between University of New South Wales (UNSW), Sydney, and a multidisciplinary team from Australian Red Cross Lifeblood Milk.
The study also found that cold storage of human milk having the virus (either at 4°C or −30°C) did not significantly impact infectious viral load over a 48-hour period.
The journal advised women with COVID-19 to continue breastfeeding their infants.
The World Health Organization (WHO) also recommends that mothers with suspected or confirmed COVID-19 should be encouraged to continue to breastfeed. Mothers should be counselled that the “benefits of breastfeeding substantially outweigh the potential risks for transmission,” it added.
The WHO also recommends feeding donated breast milk when the mother’s own milk is not available, to reduce the risks of some health challenges premature babies can face.
According to Greg Walker, lead author and PhD candidate at UNSW Medicine:
“While there is no evidence that the virus can be transmitted through breast milk, there is always a theoretical risk. We’ve seen in previous pandemics that pasteurised donor human milk (PDHM) supplies may be interrupted because of safety considerations.”
Walker added the researchers are “confident about the results of the study” for the amount of virus they used in milk for research was much higher than what would be found in breast milk.
Kirby Institute researcher and study co-author, Stuart Turville, claimed the study was the first of its kind.
“We’ve been working in real time to grow and make tools against this new pathogen, which has been an exponential learning curve for everyone involved. This work and many others that are continuing tell us how we can be safe at the front line working with this virus in the real world,” Turville said.
The researchers added that SARS-CoV-2 was stable in refrigerated or frozen human milk, and the same could help inform guidelines around safe storing of milk from COVID-19 infected mothers.