The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) has advised that no breastfeeding woman should receive the Pfizer-BioNTech covid-19 vaccine. NHS Trusts have interpreted this as a blanket-ban. The decision disregards an individual’s particular level of exposure to the virus or her likelihood of developing a severe form of the disease. The MHRA’s stance, and associated restrictions around pregnancy, could undermine efforts to achieve high levels of vaccination, and worsen the UK’s already low breastfeeding rates.
Breastfeeding women have been excluded from the Pfizer, AstraZeneca and Moderna vaccine trials. To date, no plausible biological mechanism for how an inactivated, recombinant vaccine would cause harm to a breastfed baby has been proposed.  However, any data gap leaves open a possibility of risk. Yet men who are trying to conceive can be vaccinated, even though no data exists about the vaccine’s effect on spermatogenesis. Regarding lactation, theoretical risk must be weighed against the established benefits of acquiring immunity to covid-19 and of continued breastfeeding.
The Green Book, which provides information on vaccines in the UK, does not offer further explanation for the MHRA’s decision, merely stating that the licensor has “advised vaccination should not be given whilst breastfeeding.”  Refusal to vaccinate those who are breastfeeding is an attempt to protect women and infants, The Green Book authors suggest, who conclude that the MHRA has taken “a very precautionary approach.” But in our view, the approach is not cautious; it is reckless to insist on exposing these women, their families and—in the case of healthcare workers—their patients, to a potentially lethal virus.
Surely the number of doctors, nurses, and carers at work who are breastfeeding is vanishingly small? This seems to be the assumption made by the MHRA. That several thousand doctors and healthcare workers are breastfeeding while caring for patients may come as a surprise to many. But it shouldn’t. Guidelines from the NHS and WHO strongly support breastfeeding until an infant is two years of age and beyond. It is often wrongly presumed that these targets apply only to women in developing countries and that for mothers in the UK, breastfeeding ceases to be worthwhile after six months. No wonder breastfeeding rates in the UK are some of the lowest in the world, with 8 out of 10 women stopping before they want to. 
To support breastfeeding beyond the first few months is a public health priority which policy makers cannot afford to ignore. Healthcare workers feel overlooked by the MHRA’s guidance, which reinforces society’s perception of breastfeeding as a lifestyle choice. This belies the effort and expense incurred by those who breastfeed, a physically and emotionally demanding commitment which does not come naturally to many infants or their mothers. The benefits of breastfeeding extend beyond a source of calories, and the milk’s immunological components increase with age.  Many women cite the importance of breastfeeding for their mental health, and as a powerful way to reconnect with their baby after a day’s separation. Any woman should be enabled to continue breastfeeding for valid reasons of maternal and infant comfort, health promotion or medical necessity.
The US approach to the Pfizer-BioNTech vaccine has been quite different. Recommendations from The Advisory Committee on Immunization Practices (ACIP), approved by the Centers for Disease Control (CDC), conclude that breastfeeding women may choose to receive the vaccine. The American College of Obstetricians and Gynecologists (ACOG) released a Practice Advisory and its message is clear: “vaccines should not be withheld from lactating individuals who otherwise meet criteria for vaccination.” Even the more cautious wording of the vaccine’s Emergency Use Authorization (EUA) recommends a discussion between a breastfeeding woman and her healthcare provider, which leaves open the option of vaccination.  Breastfeeding women in the UK should also be given the choice to accept or decline the vaccine.
Women on the NHS frontline currently face three unthinkable options: accept the vaccine and stop breastfeeding before they or their baby are ready; be denied the vaccine and continue to breastfeed; or accept the vaccine but “fail to disclose” they are nursing. The first assumes that benefits of the vaccine outweigh those of breastfeeding. Stopping feeding abruptly is not like cancelling a subscription: it is associated with negative emotions, known as breastfeeding grief, risk of engorgement and mastitis, as well as being a sudden physical and emotional transition for a child.  Women who choose to continue to breastfeed, who want to get vaccinated but cannot, and who work in high-risk settings, are unwillingly exposed to infection.  Being so-called “unvaccinated by choice” drags women into workplace tensions around the staffing of “hot zones”, debates about professionalism and patient safety, resentment about required periods of isolation, and some even fear discrimination when they apply for a future promotion or locum work. Lying about breastfeeding continuation puts a healthcare worker in breach of her duty to act with honesty and integrity.  Nevertheless, many doctors feel personally and professionally conflicted, and have told us they would be prepared to lie in order to receive the vaccine.
Allowing breastfeeding women to receive a covid-19 vaccine should not set a precedent for condoning gaps in evidence. Robust data on the vaccines’ safety in breastfeeding must be an urgent priority. Currently no European trials are underway in humans to collect such data, thereby blocking the route to correct this inequality. There is willingness among many breastfeeding healthcare workers to be vaccinated and studied. On one UK-based Facebook group alone, over 400 breastfeeding doctors stated their enthusiasm to be vaccinated, to share their data and even donate milk samples for analysis. But until any formal data becomes available, regulators must recognise a breastfeeding woman’s agency to be responsible for her own choice about receiving the vaccine.
This data gap is not an anomaly. It is the result of a system of researching and licensing drugs that routinely discriminates against women, excludes them from the evidence base, and denies them the right to make informed risk-benefit decisions about their own health. We implore the MHRA to change its position.
Helen Hare is an Acute Medicine CT2 working in Emergency Medicine and is breastfeeding an 18-month-old.
Kate Womersley is an Academic FY2 and is breastfeeding a 9-month-old.
Competing interests: None declared
1. Unlike the Pfizer vaccine, the AstraZeneca Covid-19 vaccine contains a live adenovirus vector, but this virus is not replicating and does not cause infection in the recipient.
5. GPs are already overwhelmed. The feasibility of consultations on an individual basis in the NHS is questionable, and in the absence of further data, it’s not clear what their expertise would add.
7. This is especially relevant for women with pre-existing conditions or from minority ethnic groups who are at increased risk of severe covid-related illness. https://www.nhs.uk/conditions/coronavirus-covid-19/people-at-higher-risk/whos-at-higher-risk-from-coronavirus/