Infant Feeding and Risk of a Positive SARS-CoV-2 Test
by Anne Eglash MD, IBCLC, FABM
There has been a great deal in the media about how lactating parents with a history of COVID-19 infection or COVID vaccination generate antibodies in their breastmilk. Although it is hoped and assumed that these antibodies will protect from SARS-CoV-2, we don’t have much data on whether breastfed children have lower rates of symptomatic COVID-19 infection.
If you are reading this, no doubt you know that there are many other factors in human milk that play a role in decreasing the severity of viral and bacterial infections. COVID-19 infection is so much more than a respiratory infection, given that it can also cause significant bodily inflammation such as the multisystem inflammatory disorder in infants and children. Because human milk has many factors that are not only anti-infective but also anti-inflammatory and immune-regulating, one would expect that breastfed infants/children would have a lowered risk of severe symptoms and inflammation from COVID-19.
Today’s article is an analysis of data collected from an ongoing multicenter observational study of clinical and epidemiological features of children who were seen at one of 13 pediatric emergency departments (EDs) in Majorca, Spain during late summer and fall 2020. The authors analyzed the association between infant feeding type, the risk of testing positive for SARS-CoV-2, and associated symptoms of COVID-19.
The study collected a great deal of demographic and past medical history information regarding 691 children who presented to the ED. Each child had their BMI measured in the ED. The breastfeeding data only consisted of one question, ‘Was the child ever breastfed directly at the breast’.
Sixty-eight % of the children, on average 54.6 months of age, ever-breastfed. The 32% who were never breastfed were on average 48 months old.
They found that among all children, 1/25 had a positive test for SARS-CoV-2, but only 1/60 of every breastfed child tested positive for SARS-CoV-2.
- The ever- breastfed children had a lower body mass index (BMI) than the formula fed infants.
- The formula fed infants had a higher rate of acute otitis media (ear infection) as compared to the ever-breastfed children.
- Among the children positive for SARS-CoV-2, those who were formula fed were much more likely to be admitted to the hospital compared to those who were ever-breastfed.
See the Answer
It has been demonstrated that children who had been breastfed remain better protected against various infections, and notably respiratory tract infections, well beyond infancy. Since the role of breastfeeding to explain why children are less affected by COVID-19 has not been studied until now, the aim of this study was to determine whether any history of breastfeeding reduces the incidence rate of COVID-19 in children.
This was a secondary analysis of an observational study on clinical and epidemiological characteristics of pediatric COVID-19 in Majorca. A total of 691 children were recruited during the 5 months of August–December 2020. Eligible participants were children under 14 who were tested for SARS-CoV-2 in pediatric emergency services. The independent explanatory variable was any breastfeeding. Bivariate analyses were conducted through the Chisquare test, the Fisher’s Exact test or the Student’s T test. All children had the same demographic, epidemiological and clinical data collected through a study team member interview and via the participants medical records.
Within the sample of children who visited emergency services with symptoms of potential COVID-19, we found higher prevalence of positive SARS-CoV-2 RT-PCR test results among those who were exclusively formula fed compared with those who were ever breastfed (OR 2.48; 95% CI 1.45, 3.51; P = 0.036).
The present study suggests that ever breastfeeding reduces the risk of COVID-19 among children, as documented for other infections.
The good news is that in general, infants and young children are at much lower risk of severe COVID-19 illness as compared to adults. In this study of 691 children, only 1, age 13, was hospitalized for COVID-19 symptoms. He was not breastfed.
This study does not prove cause and effect between breastfeeding and a positive SARS-CoV-2 test, but the difference in the rate of positivity for SARS-CoV-2 virus is impressive. It is hard to investigate this topic because so few infants and young children develop severe COVID illness. Also, this data was collected before the Delta-variant was widespread. Hopefully more research findings will emerge over time.
Comparing BMI and rates of ear infections among ever-breastfed and formula-fed infants was not an aim of this research, but their results support the myriad of other studies that demonstrate a higher BMI and higher rate of ear infections among never-breastfed children.