Detection of Messenger RNA COVID-19 Vaccines in Human Breast Milk

Authors: Nazeeh Hanna, MD1Ari Heffes-Doon, MD1Xinhua Lin, PhD2et alClaudia Manzano DeMejia, MD2Bishoy Botros, BS2;  Ellen Gurzenda, BS2Amrita Nayak, MD1 JAMA Pediatric Published online September 26, 2022. doi:10.1001/jamapediatrics.2022.3581

Vaccination is a cornerstone in fighting the COVID-19 pandemic. However, the initial messenger RNA (mRNA) vaccine clinical trials excluded several vulnerable groups, including young children and lactating individuals.1 The US Food and Drug Administration deferred the decision to authorize COVID-19 mRNA vaccines for infants younger than 6 months until more data are available because of the potential priming of the children’s immune responses that may alter their immunity.2 The Centers for Disease Control and Prevention recommends offering the COVID-19 mRNA vaccines to breastfeeding individuals,3 although the possible passage of vaccine mRNAs in breast milk resulting in infants’ exposure at younger than 6 months was not investigated. This study investigated whether the COVID-19 vaccine mRNA can be detected in the expressed breast milk (EBM) of lactating individuals receiving the vaccination within 6 months after delivery.

Methods

This cohort study included 11 healthy lactating individuals who received either the Moderna mRNA-1273 vaccine (n = 5) or the Pfizer BNT162b2 vaccine (n = 6) within 6 months after delivery (Table 1). Participants were asked to collect and immediately freeze EBM samples at home until transported to the laboratory. Samples of EBM were collected before vaccination (control) and for 5 days postvaccination. A total of 131 EBM samples were collected 1 hour to 5 days after vaccine administration. Extracellular vesicles (EVs) were isolated in EBM using sequential centrifugation, and the EV concentrations were determined by ZetaView (Analytik) (eMethods in the Supplement). The presence of COVID-19 vaccine mRNA in different milk fractions (whole EBM, fat, cells, and supernatant EVs) was assayed using 2-step quantitative reverse transcriptase–polymerase chain reaction. The vaccine detection limit was 1 pg/mL of EBM (eMethods in the Supplement).

Results

Of 11 lactating individuals enrolled, trace amounts of BNT162b2 and mRNA-1273 COVID-19 mRNA vaccines were detected in 7 samples from 5 different participants at various times up to 45 hours postvaccination (Table 2). The mean (SD) yield of EVs isolated from EBM was 9.110 (5.010) particles/mL, and the mean (SD) particle size was 110.0 (3.0) nm. The vaccine mRNA appears in higher concentrations in the EVs than in whole milk (Table 2). No vaccine mRNA was detected in prevaccination or postvaccination EBM samples beyond 48 hours of collection. Also, no COVID-19 vaccine mRNA was detected in the EBM fat fraction or the EBM cell pellets.

Discussion

The sporadic presence and trace quantities of COVID-19 vaccine mRNA detected in EBM suggest that breastfeeding after COVID-19 mRNA vaccination is safe, particularly beyond 48 hours after vaccination. These data demonstrate for the first time to our knowledge the biodistribution of COVID-19 vaccine mRNA to mammary cells and the potential ability of tissue EVs to package the vaccine mRNA that can be transported to distant cells. Little has been reported on lipid nanoparticle biodistribution and localization in human tissues after COVID-19 mRNA vaccination. In rats, up to 3 days following intramuscular administration, low vaccine mRNA levels were detected in the heart, lung, testis, and brain tissues, indicating tissue biodistribution.4 We speculate that, following the vaccine administration, lipid nanoparticles containing the vaccine mRNA are carried to mammary glands via hematogenous and/or lymphatic routes.5,6 Furthermore, we speculate that vaccine mRNA released into mammary cell cytosol can be recruited into developing EVs that are later secreted in EBM.

The limitations of this study include the relatively small sample size and the lack of functional studies demonstrating whether detected vaccine mRNA is translationally active. Also, we did not test the possible cumulative vaccine mRNA exposure after frequent breastfeeding in infants. We believe it is safe to breastfeed after maternal COVID-19 vaccination. However, caution is warranted about breastfeeding children younger than 6 months in the first 48 hours after maternal vaccination until more safety studies are conducted. In addition, the potential interference of COVID-19 vaccine mRNA with the immune response to multiple routine vaccines given to infants during the first 6 months of age needs to be considered. It is critical that lactating individuals be included in future vaccination trials to better evaluate the effect of mRNA vaccines on lactation outcomes.

References

1.Van Spall  HGC.  Exclusion of pregnant and lactating women from COVID-19 vaccine trials: a missed opportunity.   Eur Heart J. 2021;42(28):2724-2726. doi:10.1093/eurheartj/ehab103PubMedGoogle ScholarCrossref

2.US Food and Drug Administration. Coronavirus (COVID-19) update: FDA authorizes Moderna and Pfizer-BioNTech COVID-19 vaccines for children down to 6 months of age. Released June 17, 2022. https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-authorizes-moderna-and-pfizer-biontech-covid-19-vaccines-children

3.Centers for Disease Control and Prevention. COVID-19 vaccines while pregnant or breastfeeding. Accessed March 8, 2021. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/pregnancy.html.

4.European Medicines Agency. Assessment report: COVID-19 vaccine Moderna. Published March 11, 2021. http://www.ema.europa.eu/en/documents/assessment-report/spikevax-previously-covid-19-vaccine-moderna-epar-public-assessment-report_en.pdf.

5.Pardi  N, Tuyishime  S, Muramatsu  H,  et al.  Expression kinetics of nucleoside-modified mRNA delivered in lipid nanoparticles to mice by various routes.   J Control Release. 2015;217:345-351. doi:10.1016/j.jconrel.2015.08.007PubMedGoogle ScholarCrossref

6.Bansal  S, Perincheri  S, Fleming  T,  et al.  Cutting edge: circulating exosomes with COVID spike protein are induced by BNT162b2 (Pfizer-BioNTech) vaccination prior to development of antibodies: a novel mechanism for immune activation by mRNA vaccines.   J Immunol. 2021;207(10):2405-2410. doi:10.4049/jimmunol.2100637PubMedGoogle ScholarCrossref

Detection of Messenger RNA COVID-19 Vaccines in Human Breast Milk

Authors: Nazeeh Hanna, MD1Ari Heffes-Doon, MD1Xinhua Lin, PhD2et al JAMA Pediatr. Published online September 26, 2022. doi:10.1001/jamapediatrics.2022.3581

Vaccination is a cornerstone in fighting the COVID-19 pandemic. However, the initial messenger RNA (mRNA) vaccine clinical trials excluded several vulnerable groups, including young children and lactating individuals.1 The US Food and Drug Administration deferred the decision to authorize COVID-19 mRNA vaccines for infants younger than 6 months until more data are available because of the potential priming of the children’s immune responses that may alter their immunity.2 The Centers for Disease Control and Prevention recommends offering the COVID-19 mRNA vaccines to breastfeeding individuals,3 although the possible passage of vaccine mRNAs in breast milk resulting in infants’ exposure at younger than 6 months was not investigated. This study investigated whether the COVID-19 vaccine mRNA can be detected in the expressed breast milk (EBM) of lactating individuals receiving the vaccination within 6 months after delivery.

Methods

This cohort study included 11 healthy lactating individuals who received either the Moderna mRNA-1273 vaccine (n = 5) or the Pfizer BNT162b2 vaccine (n = 6) within 6 months after delivery (Table 1). Participants were asked to collect and immediately freeze EBM samples at home until transported to the laboratory. Samples of EBM were collected before vaccination (control) and for 5 days postvaccination. A total of 131 EBM samples were collected 1 hour to 5 days after vaccine administration. Extracellular vesicles (EVs) were isolated in EBM using sequential centrifugation, and the EV concentrations were determined by ZetaView (Analytik) (eMethods in the Supplement). The presence of COVID-19 vaccine mRNA in different milk fractions (whole EBM, fat, cells, and supernatant EVs) was assayed using 2-step quantitative reverse transcriptase–polymerase chain reaction. The vaccine detection limit was 1 pg/mL of EBM (eMethods in the Supplement).

Results

Of 11 lactating individuals enrolled, trace amounts of BNT162b2 and mRNA-1273 COVID-19 mRNA vaccines were detected in 7 samples from 5 different participants at various times up to 45 hours postvaccination (Table 2). The mean (SD) yield of EVs isolated from EBM was 9.110 (5.010) particles/mL, and the mean (SD) particle size was 110.0 (3.0) nm. The vaccine mRNA appears in higher concentrations in the EVs than in whole milk (Table 2). No vaccine mRNA was detected in prevaccination or postvaccination EBM samples beyond 48 hours of collection. Also, no COVID-19 vaccine mRNA was detected in the EBM fat fraction or the EBM cell pellets.

Discussion

The sporadic presence and trace quantities of COVID-19 vaccine mRNA detected in EBM suggest that breastfeeding after COVID-19 mRNA vaccination is safe, particularly beyond 48 hours after vaccination. These data demonstrate for the first time to our knowledge the biodistribution of COVID-19 vaccine mRNA to mammary cells and the potential ability of tissue EVs to package the vaccine mRNA that can be transported to distant cells. Little has been reported on lipid nanoparticle biodistribution and localization in human tissues after COVID-19 mRNA vaccination. In rats, up to 3 days following intramuscular administration, low vaccine mRNA levels were detected in the heart, lung, testis, and brain tissues, indicating tissue biodistribution.4 We speculate that, following the vaccine administration, lipid nanoparticles containing the vaccine mRNA are carried to mammary glands via hematogenous and/or lymphatic routes.5,6 Furthermore, we speculate that vaccine mRNA released into mammary cell cytosol can be recruited into developing EVs that are later secreted in EBM.

The limitations of this study include the relatively small sample size and the lack of functional studies demonstrating whether detected vaccine mRNA is translationally active. Also, we did not test the possible cumulative vaccine mRNA exposure after frequent breastfeeding in infants. We believe it is safe to breastfeed after maternal COVID-19 vaccination. However, caution is warranted about breastfeeding children younger than 6 months in the first 48 hours after maternal vaccination until more safety studies are conducted. In addition, the potential interference of COVID-19 vaccine mRNA with the immune response to multiple routine vaccines given to infants during the first 6 months of age needs to be considered. It is critical that lactating individuals be included in future vaccination trials to better evaluate the effect of mRNA vaccines on lactation outcomes.

References

1. Van Spall  HGC.  Exclusion of pregnant and lactating women from COVID-19 vaccine trials: a missed opportunity.   Eur Heart J. 2021;42(28):2724-2726. doi:10.1093/eurheartj/ehab103PubMedGoogle ScholarCrossref

2. US Food and Drug Administration. Coronavirus (COVID-19) update: FDA authorizes Moderna and Pfizer-BioNTech COVID-19 vaccines for children down to 6 months of age. Released June 17, 2022. https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-authorizes-moderna-and-pfizer-biontech-covid-19-vaccines-children

3. Centers for Disease Control and Prevention. COVID-19 vaccines while pregnant or breastfeeding. Accessed March 8, 2021. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/pregnancy.html.

4. European Medicines Agency. Assessment report: COVID-19 vaccine Moderna. Published March 11, 2021. http://www.ema.europa.eu/en/documents/assessment-report/spikevax-previously-covid-19-vaccine-moderna-epar-public-assessment-report_en.pdf.

5. Pardi  N, Tuyishime  S, Muramatsu  H,  et al.  Expression kinetics of nucleoside-modified mRNA delivered in lipid nanoparticles to mice by various routes.   J Control Release. 2015;217:345-351. doi:10.1016/j.jconrel.2015.08.007PubMedGoogle ScholarCrossref

6. Bansal  S, Perincheri  S, Fleming  T,  et al.  Cutting edge: circulating exosomes with COVID spike protein are induced by BNT162b2 (Pfizer-BioNTech) vaccination prior to development of antibodies: a novel mechanism for immune activation by mRNA vaccines.   J Immunol. 2021;207(10):2405-2410. doi:10.4049/jimmunol.2100637PubMedGoogle ScholarCrossref

UK Govt Denies ‘Safe Use’ Recommendation for Pfizer Vaccine In Pregnant Women, Says Those Breastfeeding Should NOT Be Vaccinated.

FURTHER STUDIES ARE BEING CONDUCTED TO ASCERTAIN MORE DETAILS ABOUT THE IMPACT OF THE VACCINES.

Authors:  NATALIE WINTERS AUGUST 30, 2022 The National Pulse

The British government has recommended against pregnant and breastfeeding women receiving the Pfizer COVID-19 vaccine, admitting that “sufficient reassurance of safe use of the vaccine” for the demographic “cannot be provided at the present time.”

The findings were revealed in a comprehensive report from the country’s Department of Health and Social Care, “Summary of the Public Assessment Report for COVID-19 Vaccine Pfizer/BioNTech,” last updated on August 16th. The report was published through the government’s Medicines & Healthcare products Regulatory Agency.

The report’s “Toxicity Conclusions” section outlines why the department recommends against pregnant and breastfeeding women receiving the vaccine, noting:

“In the context of supply under Regulation 174, it is considered that sufficient reassurance of safe use of the vaccine in pregnant women cannot be provided at the present time: however, use in women of childbearing potential could be supported provided healthcare professionals are advised to rule out known or suspected pregnancy prior to vaccination. Women who are breastfeeding should also not be vaccinated.

“The absence of reproductive toxicity data is a reflection of the speed of development to first identify and select COVID-19 mRNA Vaccine BNT162b2 for clinical testing and its rapid development to meet the ongoing urgent health need. In principle, a decision on Licensing a vaccine could be taken in these circumstances without data from reproductive toxicity studies animals, but there are studies ongoing and these will be provided when available,” continued the report.

The admission follows controversy over several Western governments’ hasty approvals and, in some cases, mandates of COVID-19 vaccines.

In the U.S., following a massive lobbying campaign by pharmaceutical giants including Pfizer, many jobs, businesses, and schools required COVID-19 vaccination for entry. As a result, companies including Pfizer have enjoyed record-breaking profits throughout the COVID-19 pandemic.

The British government’s report also follows U.S. health agencies such as the Food and Drug Administration (FDA) appearing to slow roll the release of data relevant to the efficacy and long-term health implications of the COVID-19 vaccine.