Breastfeeding has multiple benefits for both mother and babies. Apart from its richness from the nutritional point of view, the high content of immunoglobulins in colostrum and breast milk is the first and safest ‘vaccine’ that the infant can receive, since it confers protection against multiple infections in the first weeks and months of life.
In the neonatal period, babies are exposed to a myriad of microorganisms, whose main entry point is mucosal barriers. Instead, initially with an immature immune system to be able to cope with pathogens.
Breast milk contains many components of innate – non-specific – and acquired immunity – specific defenses acquired by the mother’s previous experience – which are transmitted to babies, thus generating active and passive protection against infection.
In this sense, breast milk contributes to a reduction important of infant morbidity and mortality, when exclusive breastfeeding is carried out for at least the first six months of the baby’s life.
The current COVID-19 pandemic has caused great concern among nursing mothers for different reasons.
At the beginning of the pandemic, these concerns focused on the possibility of contagion, to the point that in many settings breastfeeding had become contraindicated in women with a positive diagnosis of COVID-19.
However, several studies have already shown that the virus is not transmitted through breast milk and that it also contains specific antibodies against the virus in women who have had the disease. This evidence has led to the recommendation not to interrupt breastfeeding in case of contracting the infection, although it is recommended continue to take extreme measures of protection and hygiene during breastfeeding as far as possible.
Vaccination during breastfeeding
More recently, with the approval of the SARS-CoV-2 vaccines, fears have centered on the potential harmful effects that vaccines could have on infants while breastfeeding.
In this sense, many professionals contraindicate them in the absence of scientific evidence; or they leave the choice of vaccination and / or breastfeeding in the hands of mothers, based on the risk of covid-19 to which they are exposed.
Legislation allows clinical trials in pregnant and lactating women, provided they are of benefit to the woman or the baby
The legislation The current law allows clinical trials with drugs in pregnant and lactating women, provided that these may be of benefit to the woman or the baby. However, the ethical fears and dilemmas this raises are many. So the safety of most drugs during breastfeeding, including vaccines, is limited to monitoring them in the post-marketing period.
Faced with this scenario, professionals from the Sant Joan de Déu Sanitary Park who carry out their work on the front line, who are nursing mothers and wanted to be vaccinated, decided to undertake research in this field.
Thus, with the help of Dr. Erika Esteve, deputy physician of the Infectious Diseases Service of the Sant Boi Hospital, and her entire team, with Dr. Vicens Díaz de Brito at the helm, the LacCOVID study, recently published in the repository medRxiv.
The results show that vaccination with the Pfizer / BioNTech vaccine is safe during breastfeeding and that it also transmits antibodies to breast milk.
The 32 pioneers: sanitary, vaccinated and nursing mothers
Together with Erika, 31 more women, thanks to their courage, have participated in this pioneering work. Although this is a small cohort and the follow-up has not yet been completed – expected at six months – these data suggest that, as with other infectious diseases or with other vaccines, babies breastfed by immunized women could be protected against to covid-19, at least while breastfeeding lasts.
The time period for this transmission of antibodies to breast milk is yet to be determined, but according to the data analyzed, it is expected that it will continue for as long as the levels of antibodies in the blood last.
This cohort includes only women vaccinated with Pfizer / BioNTech, but another study Recent shows that the results can be extrapolated to women vaccinated with Moderna.
In addition, there are other studies underway with vaccines other than the previous two, both based on messenger RNA technology, which will soon offer more data in this field.
Finally, there are other studies underway with different vaccines in nursing mothers that will allow us to determine the levels of immune response and their passage into breast milk. This will contribute to a deeper understanding of the protective role of breast milk against covid-19.