NCoV-19 Coronavirus vaccine

"The vaccine (COVID-19) can be offered to a breastfeeding woman who is part of a group recommended for vaccination (e.g. health workers); discontinuing breastfeeding after vaccination is currently not recommended". ^{(WHO 2021/01/25)}

Several types of vaccines are currently in development against COVID-19, among those in production there are ^{(WHO 2021/01/26)}:

• Messenger ribonucleic acid vaccines (mRNA): BNT162b2-Tozinameran-Comirnaty (Pfizer-BioNTech), MRNA-1273 (Moderna & NIH) and CVnCoV (Cure Vac). This type of vaccine uses portions of mRNA replicated from coronavirus n-19 to induce the synthesis and production of coronavirus n-19 surface proteins from muscle cells located at the site of injection that then act as triggers for the production of antibodies against the COVID-19 virus by the immune system.
• Viral vector-based vaccines: AZD1222-Vaxzevria Oxford-AstraZeneca vaccine (Covishield in India), Gam-COVID-Vac (Gamaleya-Sputnik V), Cansino vaccine and Ad26.COV2.S-Janssen COVID-19 Vaccine (Johnson & Johnson). These vaccines use a non-pathogenic strain of human adenovirus that has been modified to contain genetic material that resembling a portion of coronavirus 2019-nCoV that can induce the immune system to react in a way similar to what was previously described with mRNA vaccines.
• Inactivated virus vaccines: Coronavac from Sinovac, Covaxin (BBV152-Bharat Biotech) and Sinopharm vaccines.These vaccines are manufactured with dead viruses that do not have the capacity to reproduce or infect. These vaccines cause our immune system to react and start the production of specific antibodies against the COVID-19 virus.

Currently breastfeeding women have been excluded from all pre-marketing clinical trials. ^{(Palacios 2020, Costantine 2020, CDC 2020/12/15, ABM 2020/12/14)}

There were no significant differences between nursing mothers and non-lactating women in terms of side effects and the rate of antibodies generated after the COVID-19 vaccine. ^{(Romero 2022/03, Falsaperla 2021/10, Perl 2021/04, Gray 2021/03)} 

COVID vaccines cause rare and minimal adverse effects in breastfeeding or nursing infants.^{(Romero 2022/03, Falsaperla 2021/10,} ​​​​^{​​Low 2021/10, McLaurin 2021/06)} Infants of vaccinated mothers did not present any serious problems attributable to vaccination. ^{(Low 2021/10, Perl 2021/04, Gray 2021/03)}  Few cases of transient increase or decrease in milk production, change to a blue-green color of the milk and irritability-insomnia have been published in the infant, more frequent after the second dose of vaccine.^{(Lamers 2022/04, Bertrand 2021/09)}

As expected ^{(Baird 2021/02, InfantRisk 2020/12, ABM 2020/12)} as after vaccination against other viruses, in the milk of lactating mothers vaccinated against COVID-19 appear high positivity rates for IgA and IgG antibodies generated by the vaccine, which would protect the infant from COVID-19. ^{(Whited 2022/03, Falsaperla 2021/10, Valcarce 2021/08, Collier 2021/05, Perl 2021/04, Kelly 2021/03, Gray 2021/03)} 

The IgA and IgG antibody response in breast milk is greater and more frequent with mRNA-m vaccines (Pfizer and Moderna) than with adenovirus-vectored vaccines (AstraZeneca and Janssen). ^{(Selma 2022/04, Juncker 2022/03)}

The longer breastfeeding (> 23 months) there is a higher rate of IgG and IgA antibodies in breast milk among lactating women vaccinated with the COVID19 vaccine. ^{(Ramírez 2021/08)}

It is highly improbable that any of the components that are part of the vaccines produced against COVID-19 could be excreted through human breastmilk, and even in this could happen, they would all be digested in the gastrointestinal tract of the breastfeeding child ^{(InfantRisk 2020/12)} After vaccination, no COVID-19 vaccine-related messenger RNA has been detected in breast milk.^{(Golan 2021/10)}

Neither of the types of vaccines currently in development against COVID-19 contain live viruses within their components and therefore cannot provoke the disease or cause any alterations to the genetic material of their host. ^{(CDC 2020/12/18 y 2020/12/13)} Except for three live attenuated virus vaccines (small pox, yellow fever and oral polio-Sabin) that are known to rarely bring about negative effects on breastfeeding children, all vaccines are to be regarded as safe for use during lactation and therefore can be prescribed to breastfeeding women. ^{(CDC 2020/02)} 

Breastfeeding women are not considered to be a high-risk group for COVID-19, specially since they tend to be young and usually healthy and therefore until now there are no specific reasons that would warrant the use of the vaccine in this group. Several Health institutions, medical societies and also expert consensus have suggested that the vaccine should be prescribed for breastfeeding women if they would also belong to a high-risk group such as healthcare workers or people afflicted by a chronic disease or condition known to be a risk factor. ^{(Mayo 2021/03, Davanzo 2021/02, Saus 2021/02, Chervenak 2021/02, WHO 2021/01, Sax 2021, IHAN 2021, AELAMA 2021, NHS 2021, HIFN 2020, MS España 2020/12, ACOG 2020/12, CDC 2020/12 y 2020/12)} 

Vaccinating against COVID-19 should not be an impediment to begin lactation nor a cause for its interruption. ^{(Terezia 2023, Davanzo 2021/02, Chervenak 2021/02, ACOG 2020/12)} At the end of the year 2020; AstraZeneca, Moderna and Pfizer withdrew from their respective drug leaflets the previous recommendation of not administering their vaccines to lactating mothers. ^{(Moderna 2021, AstraZeneca 2021, Pfizer 2020)} 

As it may happen with other vaccinations, after the COVID-19 vaccination, palpable axillary lymph nodes may appear on the same side of the vaccine injection. A clinical follow-up of the nodes would be enough to rule out a presumed malignancy at the level of the breast. Costly and unnecessary complementary examinations should be avoided.^{(Low 2021/10, Edmonds 2021, Mehta 2021)} This is a transitory side effect that usually does not disrupt the continuity of breastfeeding.

See below the information of this related product:

• Maternal Coronavirus 2019-nCoV infection (COVID-19) (Safe substance and/or breastfeeding is the best option.)