According to the World Health Organization (WHO, 2022), breastfeeding is essential for child survival and health, yet ‘it is estimated that inadequate breastfeeding is responsible for 16% of child deaths each year’. While the United Nations Children's Fund (UNICEF, 2023) notes that breastfeeding initiation in the UK stands at 81%, Ireland's Health Service Executive (HSE) reported that the breastfeeding initiation rate in maternity hospitals in Ireland is among the lowest in the world at 63.8% (HSE, 2020).
However, Irish researchers are meeting the challenge of increasing breastfeeding rates while also addressing the role of breastfeeding in mitigating the effects of infections like respiratory syncytial virus (RSV) among infants.
Breastfeeding in Ireland
Culturally embedded attitudes such as embarrassment about breastfeeding in public and adherence to deep-rooted societal norms can blunt the beneficial impact of public health initiatives on breastfeeding. But deprivation can also contribute to suboptimal levels of the practice, with Limerick city in the west of Ireland having one of the country's lowest rates of breastfeeding. A team led by consultant paediatrician and neonatologist Professor Roy Philip of University Maternity Hospital Limerick analysed inter alia breastfeeding initiation rates over the last 20 years for Ireland's Mid-West region and established evidence-based priorities to improve Irish breastfeeding rates (Philip et al, 2022).
The team found that the number of infants that initiated breastfeeding rose from 41% in 2001 to 61.4% in 2020, and that both exclusive breastfeeding and combined feeding (breastfeeding and formula feeding) upon hospital discharge increased from 35% to 45.5% and from 6% to 13.5%, respectively. However, the percentage of infants who had any breastfeeding at discharge (either exclusive or combined) was consistently lower than the percentage that had begun breastfeeding immediately or soon after birth, indicating discontinuation of breastfeeding during the in-patient period.
Philip et al (2022) proposed 10 priorities to increase breastfeeding initiation rates in Ireland, which include advocating the advantages of breastfeeding; establishing cross-cultural peer support groups; implementing breastfeeding awareness and observation into primary and secondary education curriculums; and instituting a state-funded advertising campaign for breastfeeding.
Breastfeeding and RSV
Citing RSV as the principal global cause of acute lower respiratory infections (ALRI) among infants, and an important cause of morbidity, hospitalisation and mortality, University of Limerick researchers undertook a separate study to review the association of breastfeeding with the frequency and severity of RSV-associated ALRI among infants (Mineva et al, 2023). They evaluated 19 peer-reviewed studies that included 16 787 infants from 31 (including 8 middle-income) countries and found ‘that non-breastfeeding practices pose a significant risk for severe RSV-associated ALRI and hospitalisation. Exclusive breastfeeding for >4–6 months significantly lowered hospitalisation, length of stay, supplemental oxygen demand and admission to intensive care units’ (Mineva et al, 2023).
Report co-author Professor Colum Dunne – Foundation Chair and Director of Research at the University of Limerick's School of Medicine – told Practice Nursing that although the promotion of the many advantages conferred by breastfeeding has been broadly successful internationally, with rates of breastfeeding mothers increased significantly. However, ‘beyond general statements regarding immune enhancement there are rarely examples of specific risks provided to mothers or, indeed, healthcare professionals. This study does provide that in the context of RSV infection risk, which was prominent during last winter but occurs annually.’
How breastfeeding mitigates RSV infection
Mineva et al (2023) cite evidence to show that breastfeeding enhances the immune response against RSV-derived inflammation in airway epithelial and peripheral blood mononuclear cells (PBMC). It is also known that disease severity in viral bronchiolitis is linked to innate immunity and that the concentrations of PBMC interleukin (IL)-15 and serum IL-15 have been correlated with severity of illness in bronchiolitis. Further, it has been shown that reduced neutrophilic airway infiltration among breastfed infants lowers disease severity compared to formula-fed infants; and breast milk increases the concentration of interferon-α among RSV-infected infants ‘and decreases [the] concentration of immune modulators, such as airway chemokines and IL-8’ (Mineva et al, 2023).
Their review, says Prof Dunne, ‘underpins the message for mothers that breastfeeding confers protection of their babies against infections, some of which can have severe effects. This study and its outcomes,’ he adds, ‘may provide an understandable and easy-to-convey message for healthcare professionals, and especially nurses providing guidance to new mothers, that it is worthwhile attempting breastfeeding initially even if only for a relatively short period’.
‘Exclusive breastfeeding for >4–6 months significantly lowered hospitalisation, length of stay, supplemental oxygen demand and admission to intensive care units.’
Breastfeeding and RSV hospitalisation
Citing four studies demonstrating that breastfeeding is significantly associated with decreased rates of RSV-associated ALRI admission to hospitals, Mineva et al (2023) note the results of an Italian multicentre study that included 2154 newborns from 30 centres across the country, and reported that infants aged less than 12 months ‘faced a probability of hospitalisation for bronchiolitis of 4% in breast-fed [infants] and greater than 8% among those never fed with breast milk.’ And a further 15 peer-reviewed articles concluded that ‘breastfeeding is associated with lower risk of hospitalisation for polymerase chain reaction-confirmed RSV bronchiolitis among infants’ (Mineva et al, 2023).
RSV prophylaxis
In the absence of a widely accessible RSV vaccine, Mineva et al (2023) note that the currently available RSV-specific monoclonal antibody palivizumab is only indicated for high-risk populations, and therefore unobtainable for most susceptible infants, especially those from low- and middle-income countries. The development of prophylactic drugs that are effective against RSV is welcome, says Prof Dunne, ‘however, availability is not universal, with disparities between the developed and developing world. This inequity raises interesting questions regarding rates of breastfeeding internationally and association of RSV (and other illness) incidence and severity when corrected for breastfeeding levels.’
One such question, suggests Dunne, is whether prophylactic medicines like palivizumab ‘would be required if optimal rates of breastfeeding were achieved. This question is speculative, but the topic warrants some exploration of data from regions with high breastfeeding rates versus those with low breastfeeding rates as RSV infection will remain a recurring annual public health risk’.
Conclusion
The unseasonal post-COVID-19 epidemiological behaviour of RSV, suggest Mineva et al (2023), should provide fresh impetus to promote the value of human milk ‘against RSV disease through global initiatives, in order to harness the bioactive and immunological value of one of the most environmentally friendly primary prevention — breastfeeding’.