Breastfeeding during the COVID-19 pandemic – a literature review for clinical practice

The publications have been reviewed for the characteristics of COVID-19 in the perinatal period, the potential of transmission from infected mother to her breastfeeding infant and proposed management of healthy, exposed and infected mother-infant dyads. The findings were synthesised and a clinical guide with rationale for each suggestion provided (see Table 1) and algorithms for both healthcare providers (Additional file 1) and mothers (Additional file 2) were designed.

SARS-CoV-2 is a beta coronavirus, which cause the COVID-19 disease [11]. Currently the mode of transport of SARS-CoV-2 suggests person-to-person transmission which occurs when in close contact with an infected person. The virus is transferred via respiratory droplets produced when coughing and sneezing. Droplets can either land on a healthy individual close to a cavity in the facial area or be inhaled into the lungs of persons in close proximity. It is important to note that the airborne transmission over long distances is unlikely.

In a recent study published in The Lancet, it was stated that all the information available on pneumonia caused by the 2019 novel coronavirus disease was based on information from the general population [2]. The conclusion drawn by Qiao was that the SARS-CoV-2 may have similar pathogenesis to the SARS-CoV1 and therefore we can draw on the management of these previous epidemics to inform current practice guidelines [12].

Vertical transmission refers to the passage of a pathogen from mother to infant during the period before and after birth, including via placental blood during pregnancy, via the birth canal during labour, delivery and during postpartum feeding [1]. In their study Zhu et al. found no evidence of such vertical transmission [1]. In addition, in a retrospective review of clinical records of nine pregnant women by Chen, Guo et al., the authors found limited data available to support the transmission potential of SARS-CoV-2 from mother to child via breastmilk. They assessed the evidence of intrauterine vertical transmission by testing for the presence of the virus in amniotic fluid, cord blood, neonatal throat swab samples and breastmilk samples collected and tested from patients after the first lactation [5]. Although some case studies of infants infected with COVID-19 have been reported, it can be noted that these studies did not test for the presence of the virus in amniotic fluid, cord blood, neonatal throat swabs or breastmilk [7, 13‐15] and included only three infants in total, indicating further investigation is needed. A few case studies were published from Spain [16], Vietnam [13], China [15] and USA [17], and none of these reported transmissions of the SARS-CoV-2 via breastmilk. A systematic review by Duran et al. and a study by Lu and Shi also reported that breastmilk does not appear to be a method of transmission of the virus [18, 19]. Samples of breastmilk from 18 women infected with SARS-CoV-2 were evaluated and although SARS-CoV-2 RNA was detected in one sample of milk, the follow-up culture of the same sample was negative. It is likely that the SARS-CoV-2 RNA that was found does not contain replication-competent virus and so is unlikely to infect an infant [20]. Findings from this group of cases suggest that there is currently no evidence to show that respiratory viruses can be transmitted through breast milk.

Breastfeeding protects neonates, infants and children against morbidity and death [21, 22]. The protective effect is particularly strong against infectious diseases, due to the direct transfer of antibodies as well as anti-infective factors and long-lasting transfer of immunological competence and memory [23].

Breastfeeding has both short and long-term benefits for the mother and her infant. To benefit from the protective factors in breast milk, every effort should be made to support and enable early and immediate initiation of breastfeeding. Not only does the early initiation decrease neonatal deaths, but together with frequent breastfeeding, ensures that the breastfeeding dyad are not separated. Early initiation of breastfeeding significantly increases the breastfeeding rates in healthy term infants at one to 4 month’s age by stimulating hormones and facilitating bonding [24‐26]. The Lancet Breastfeeding Series (2016) reported that scaling up breastfeeding could prevent around 823,000 child deaths annually [21]. Breastfeeding reduces 64% of morbidity and mortality in diarrhoea, 74% in the severity of RSV and its hospitalization with 72% [22]. This demonstrates the protective benefits of breastfeeding, which pertain to COVID-19 pandemic.

The neonate has an immature immune system and colostrum, a powerful immune booster, protects infants from infections by means of bioactive factors and secretory IgA antibodies. Breast milk with its abundant source of immunoglobulins, lactoferrin, lysozyme and cytokines play an important role in absorbing and engulfing harmful micro-organisms and targeting specific bacteria and providing protection by regulating the immune response [27]. Human milk oligosaccharides, abundant in human milk, shape the microbiome, provide probiotics and modulate the developing immune system also displaying anti-adhesive effects for bacterial antigens [28‐30]. All the above are compelling reasons for every infant to receive only breast milk and preferably their own mothers’ milk.

The best way to promote successful breastfeeding, is to ensure that the mother-infant dyad is kept together, and skin-to-skin contact is supported and encouraged [31]. Skin-to-skin is the safest and best transition for mothers and their infants to a new life together. Ensuring it happens immediately after birth, the infant’s microbiome can develop from the mother’s flora, so beneficial during a pandemic [32]. Skin-to-skin also increases blood glucose levels 75–90 min after birth, improves cardiorespiratory stability [26] and significantly reduces stress levels in the infant and mother [33]. Keeping mother and infant together can reduce birth stress and even prevent neurodevelopmental disorders in the infant. The smell, touch and voice of the mother naturally calms the infant [34].

It should be noted that the WHO interim guidance documents on the management of COVID-19 has been informed by evidence-based guidelines also published by the WHO, such as the Infection prevention and control of epidemic- and pandemic-prone acute respiratory diseases in health care [35], as well as current information on COVID-19. General infection prevention measures should therefore always be taken, in all circumstances, with special attention to droplet protection. Guidance about the need for exposed and infected breastfeeding mothers to practice hand and respiratory hygiene has been given by many organisations internationally and experts in the field [36‐39]. Additional suggestions are provided based on the current knowledge of COVID-19. Based on this information, and her right to choose, the mother can make an informed choice regarding breastfeeding during the pandemic [40]. Measures for expressing breastmilk should also be applied as in normal situations, however, no equipment should be shared between mothers. All equipment used to express milk, should be rinsed with cold water and secondly washed with warm water and soap and thirdly, sterilized. In case of an epidemic it may be advisable to sterilise equipment after each use, instead of once in 24 h [27]. Another additional measure is that if a mother is potentially exposed or tested positive for COVID-19, she should use a dedicated breast pump and not share one with other mothers. She should also express in the area in which she has been isolated. A practical suggestion may be that the mother express in her container in isolation and then decant the expressed milk into a clean container held by a healthy person with appropriate protective clothing, including masks and gloves, to prevent the virus from spreading via the surface of the container. In this manner a clean container can then also be stored/milk frozen for later use without the risk of contaminating other containers with milk [41]. There has been much debate on ways to reduce the risk of the external contamination of expressed human milk containers. Marinelli and Lawrence, advise bottles to be wiped down with a viricidal agent or a dilution of 1:10 diluted bleach (sodium hypochlorite [NaOCl]) and bottles stored in separate bins for each infant in refrigerators [37]. However, concerns were expressed about the necessity to do this as no proof of contamination of bottle surfaces exists [42].

Table 1 provide a synthesis of the evidence supported recommendations for breastfeeding amidst COVID-19, based on the latest evidence as available on 15 June 2020. Information about SARS-CoV-2 transmission is emerging daily, and the latest information should always be considered in clinical decision making.

Based on the evidence presented in Table 1, a visual presentation for quick clinical reference is presented as an algorithm for healthcare professionals (Additional file 1) and mothers (Additional file 2) to support in decision-making regarding breastfeeding practices in the wake of COVID-19.