Research on mRNA COVID-19 Vaccines and Breastmilk Transmission
Introduction to COVID-19 Vaccines
Recent studies are exploring whether the mRNA from COVID-19 vaccines can be transmitted to infants through breastmilk. The introduction and distribution of SARS-CoV-2 vaccines have played a crucial role in reducing COVID-19 transmission globally. Among the first approved vaccines were mRNA vaccines, which leverage mRNA from the SARS-CoV-2 spike protein to help the immune system identify and combat the virus without causing COVID-19 infection. Currently, the two mRNA vaccines authorized for use are BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna). Research indicates that both vaccines are highly effective, with BNT162b2 demonstrating a 95% effectiveness rate and mRNA-1273 showing a 94.1% effectiveness rate. Furthermore, studies suggest that both vaccines possess an excellent safety profile, with a low likelihood of serious adverse effects.
Safety of mRNA Vaccines for Breastfeeding Women
Lactating women are encouraged to receive both the Pfizer and Moderna vaccines, as recommended by the World Health Organization (WHO). This guidance is also supported by major health organizations, including the Academy of Breastfeeding Medicine and the Centers for Disease Control and Prevention (CDC), which assert that there is no significant risk of the vaccine affecting breastmilk or tissues. This conclusion is based on several factors: the mRNA vaccines do not contain live virus, the mRNA does not alter DNA within the nucleus, and the mRNA is rapidly broken down in the body. Studies involving pregnant animals showed no safety concerns for either the mothers or their offspring. However, ethical considerations have limited clinical trials involving pregnant and lactating women, resulting in a lack of data on the safety of mRNA vaccines for breastfeeding individuals.
Detection of mRNA in Breastmilk
A study aimed to investigate whether mRNA from the COVID-19 vaccines could be found in human breastmilk. Researchers collected 13 milk samples from seven breastfeeding mothers within 48 hours post-vaccination. The average age of participants was 37.8 years, with their children’s ages ranging from one month to three years. The milk samples were immediately frozen for preservation and tested using polymerase chain reaction (PCR) for the mRNA types present in the Pfizer and Moderna vaccines. Test results were compared with samples from four participants taken before vaccination.
The study did not detect mRNA from the vaccines in any of the breastmilk samples. This finding suggests that, within this small participant group, mRNA from the vaccines was not transmitted to breastmilk or infants. However, it is important to recognize the study’s limited sample size, which may affect the broader applicability of the results. Further research involving larger populations is necessary to ascertain whether vaccine-associated mRNA can be passed through breastmilk.