COVID-19 Vaccines & Medications
Data is limited on using these medications in lactating individuals and their infants. The following information is based on currently available information on vaccines and treatment options for COVID-19.
Two systematic reviews of multiple studies found no serious adverse events have been reported in lactating women or their infants. The available evidence suggested there may be an increase, decrease, or no change in milk production with less than 10% of those studied experiencing decreased milk production. Decreases in milk production were reported to resolve within 3 days.1–3 There is no absolute indication to pump and dump after receiving COVID-19 vaccinations.
mRNA COVID-19 Vaccines
Moderna’s Spikevax and Pfizer’s Comirnaty are both mRNA COVID-19 vaccines approved for use in the United States. Other mRNA vaccinations are available in other countries. While antibodies and T-Cells to SARS-CoV2 are found in human milk after vaccination, mRNA particles are rarely detected in human milk and are gone within 48 hours in available data. mRNA particles from these vaccines have not been detected in infants after vaccination of a lactating parent. There are reports of blue or blue-green discoloration of milk after vaccination. Current literature notes lactating women may experience a decrease in milk production after mRNA vaccination against SARS-CoV2.4 Self-limited infant side effects have been reported, including increased sleepiness, increased fussiness, fever, rash, or self-limiting diarrhea.5 While parents should be counseled on the small risk to milk production, there is no absolute indication to pump and dump.
Novavax COVID-19 Vaccine
Novavax’s COVID-19 vaccine is a monovalent protein adjuvant vaccine approved for emergency use in the United States. There is no data on effects on lactation or breastfeeding infants with the use of this vaccine. However, this is not a live vaccine and is not expected to be present in human milk per the Mother to Baby fact sheet on this vaccine.6 There is no absolute indication pump and dump.
Antivirals used in the management of COVID-19 are generally not an absolute indication to pump and dump except molnupavir.
Nirmatrelvir is a nucleoside analog used in the management of acute COVID-19 in at risk patients. Nirmatrelvir has poor oral bioavailability. Ritonavir has been studied in breastfeeding mothers being treated for HIV infection and is excreted into milk in low concentrations. Low levels of ritonavir have been found in the blood of some breastfed infants though no adverse reactions have been reported. This combination is unlikely to adversely affect the breastfeeding dyad.1 Breastfeeding is not contraindicated during nirmatrelvir-ritonavir therapy in the US and Canada, but cessation of breastfeeding during its use is recommended in Europe. Until more data are available it should only be used with careful infant monitoring for adverse effects. Although there is no absolute indication to pump and dump, shared decision-making is recommended regarding this medication prior to initiating it due to there being limited data on it in lactation.
This drug has poor oral bioavailability and was previously given intravenously to patients with severe COVID-19. Even if the infant ingests this medication, it is unlikely to have significant systemic absorption or effects due to poor oral bioavailability (although studies on oral bioavailability of the active metabolite are unavailable). Infants who received this medication intravenously for Ebola treatment did not have significant adverse effects.1 While there is limited data on this medication in lactation, it has poor oral bioavailability so there is no absolute indication to pump and dump.
Efficacy is only moderate at preventing severe disease and we do not have data on the use of this medication during lactation.1 This medication is now considered an alternative treatment for COVID-19 by the United States National Institutes of Health (NIH) and should only used when Paxlovid and Remdesivir are not available.7 If this medication is used, out of an abundance of caution, lactating parents should pump and dump during treatment and for 4 days after their last dose.
Baricitinib is FDA approved for use in hospitalized patients with Remdesivir to quicken recovery. Although there is no data on milk transfer or risks to the infant, this is a small molecule which is rapidly absorbed so there is concern for high milk transfer. Due to a lack of data on both efficacy and its effects on lactation and milk transfer, barcitinib should be avoided for treatment of COVID-19 in lactating parents. If this medications is necessary for a lactating person, then lactation should be disrupted during therapy and for 4 days after the last dose per the FDA.8
These medications are generally considered safe in lactation due to their high molecular weights, low levels in breastmilk, and poor oral bioavailability with partial destruction of these molecules in the baby’s gastrointestinal tract.1
Monoclonal Antibodies (bebtelovimab, sotrovimab, tocilizumab)
Monoclonal antibodies, such as bebtelovimab, sotrovimab, and tocilizumab, have higher molecular weights and have very low levels in breastmilk. They have poor oral bioavailability and are partly destroyed by the baby’s gastrointestinal tract.1 These are no longer commonly used in the management of COVID-19. There is no absolute indication to pump and dump.
Polyclonal Antibodies (Convalescent Plasma)
The antibodies are obtained from the blood of someone who had COVID-19 previously.1 There is no absolute indication to pump and dump.
Intravenous or oral steroids are used for the management of some COVID-19 infections. High doses, particularly of IV steroids, may cause a decrease in milk production. There is no absolute indication to pump and dump. For more information on the use of steroids during lactation including considerations about milk transfer, see the section on Steroids.
(1) Anderson, P. O. COVID-19 Drugs and Breastfeeding Update. Breastfeeding Medicine 2022, 17 (5), 377–379. https://doi.org/10.1089/bfm.2022.0066.
(2) De Rose, D. U.; Salvatori, G.; Dotta, A.; Auriti, C. SARS-CoV-2 Vaccines during Pregnancy and Breastfeeding: A Systematic Review of Maternal and Neonatal Outcomes. Viruses 2022, 14 (3), 539. https://doi.org/10.3390/v14030539.
(3) Muyldermans, J.; De Weerdt, L.; De Brabandere, L.; Maertens, K.; Tommelein, E. The Effects of COVID-19 Vaccination on Lactating Women: A Systematic Review of the Literature. Front Immunol 2022, 13, 852928. https://doi.org/10.3389/fimmu.2022.852928.
(4) Bertrand, K.; Honerkamp-Smith, G.; Chambers, C. D. Maternal and Child Outcomes Reported by Breastfeeding Women Following Messenger RNA COVID-19 Vaccination. Breastfeed Med 2021, 16 (9), 697–701. https://doi.org/10.1089/bfm.2021.0169.
(5) Montalti, M.; Guaraldi, F.; Di Valerio, Z.; Ragghianti, B.; Tedesco, D.; Mannucci, E.; Monami, M.; Gori, D. Adherence to and Early Adverse Events of COVID-19 Vaccine in a Cohort of 600 Italian Breastfeeding and Pregnant Physicians. Hum Vaccin Immunother 2022, 18 (6), 2106747. https://doi.org/10.1080/21645515.2022.2106747.
(6) COVID-19 Protein Subunit Vaccine (Novavax). In Mother To Baby | Fact Sheets; Organization of Teratology Information Specialists (OTIS): Brentwood (TN), 2024.
(7) Molnupiravir. COVID-19 Treatment Guidelines. https://www.covid19treatmentguidelines.nih.gov/therapies/antivirals-including-antibody-products/molnupiravir/ (accessed 2023-11-27).
(8) Chen, M. J.; Cheema, R.; Hoyt-Austin, A.; Agnoli, A.; Kuhn-Riordon, K.; Kair, L. R. Vaccination and Treatment Options for SARS-CoV2 Infection Affecting Lactation and Breastfeeding. Semin Fetal Neonatal Med 2023, 101425. https://doi.org/10.1016/j.siny.2023.101425.