The search identified 436 citations (figure–1). After reading the titles and abstracts, 47 references met the eligibility criteria and were selected for review of the full text. At the end, 30 studies were eligible for this review. A search was also carried out on documents published by health organizations and governments as guidelines and statements that could answer the research question, 7 guidelines were identified. At the end, 37 citations were included in this review.
We separated the citations into three tables, table 1 shows the characteristics of the 12 studies included in the systematic scope review, most of the selected studies are located in China, among them, cohort studies, cross-sectional studies, case report and cross sectional were found. Table 2 presents the characteristics of 14 guidelines from different regions, including China, Italy, Portugal and London. Table 3, on the other hand, presents other 11 citations included in this study, comments, letters to the editor, protocols and other documents that answered the systematic scope review question. The synthesis of the results was divided into three topics: studies that guide the prevention of breastfeeding, studies that recommend the maintenance of breastfeeding or studies without consensus on guidelines.
It is noteworthy that for the three articles [17–21] of cross-sectional design, cohort and transversal, the risk of bias assessment was performed using the Newcastle-Ottawa scale. In all articles, the final score obtained by NOS was six.
Evidences that guide avoiding breastfeeding
Eleven citations [7, 17, 21–29] guide avoiding breastfeeding in cases of maternal infection confirmed by SARS-CoV–2. It can be seen that, based on the lack of consistent results or studies with high scientific evidence about the vertical transmission of SARS-CoV–2 by breast milk, specialists and authors are concerned to encourage breastfeeding in the current scenario, mainly of mothers suspected or infected with SARS-CoV–2 [7, 22–24, 26].
A Chinese study analyzed the presence of SARS-CoV–2 in breast milk: in two cases of mothers who are infected with SARS-CoV–2  the authors chose to advise avoiding breastfeeding during the disease period, even with negative samples for SARS-CoV–2 in maternal milk, due to the risk of transmission by contact . Additionally, it was recommended to isolate the neonate from the mother for 10 days, until the end of the period of mother’s isolation .
One study  highlighted that vertical transmission cannot be discarded, due to the lack of reliable evidence. In this specific work, mothers with SARS-CoV–2 infection were advised to avoid breastfeeding and that the newborn should receive breast milk through the donation of other women, requiring pasteurization and screening for SARS-CoV–2 in donated milk . In addition, a study  carried out in China, identified a sample of breast milk with the presence of SARS-CoV–2, however, other samples collected, presented a negative result, the author reports that the possibility of vertical transmission through breast milk cannot be excluded, and until larger studies demonstrate the safety of breast milk, it is recommended not to offer breast milk until the mother’s full recovery from infection .
Evidences without consensus on breastfeeding
Fourteen statements [18–20, 30–40] do not present a consensus on breastfeeding in cases of mothers infected with SARS-CoV–2. Two studies [30–31] report that although there are negative data for the presence of the virus in breast milk, the evidence is insufficient to guide breastfeeding, there is no consensus on the indication.
Two researches [19, 32] reported cases of a woman with the infection, however, even with negative samples for the virus in breast milk, the authors contraindicate breastfeeding because of the limitation of the sample. Guidelines have been developed [33)]in Europe to cope with SARS-CoV–2, emphasizing that it is not possible, so far, to prove transmission through breast milk. The author stressed that in China, for safety, newborns are separated from mothers confirmed for SARS-CoV–2 for 14 days, it is not advisable to offer breast milk, however, milking should be encouraged to stimulate lactation and to avoid complications resulting from not breast-feeding. The International Society of Gynecology and Obstetrics  issued guidelines for case management and the study concluded that there was no consensus on breastfeeding, due to the lack of evidence. According to the College of Specialty of Gynecology/Obstetrics of Portugal, the separation of mother and child after childbirth is a controversial issue, as the benefits of breastfeeding do not outweigh the risk of contamination of the newborn. However, he stresses that health institutions make individual decisions, taking into account the mother’s will, the facilities available in the hospital and the availability of health teams. The recommendations are added when there is a mother-child separation, it is recommended to express the milk with pump and its waste until the mother has two negative tests .
In a retrospective cohort study  with women in China, the breast milk was collected from mothers diagnosed with SARS-CoV–2 and all samples showed negative results for the infection. The authors concluded that due to the low sample size, there was not enough evidence on the safety of breastfeeding in this period. Also, a case report  with a woman with SARS-CoV–2, in which the collection of breast milk was performed after delivery, it showed a negative result for the infection in the sample, however the author reported that even with this result, vertical transmission cannot be discarded, requiring further investigation. Finally, a study carried out with a 40-year-old woman and her 8-month-old son, concluded that although two samples of breast milk showed the presence of SARS-CoV–2, the risk of contamination of the sample by the environment or by the mother was not can be discarded; considering the uncertain whether there is a risk of infection with breast milk .
Evidences that guide maintaining breastfeeding
Twelve statements [6, 10, 41–50], advised to maintain breastfeeding in confirmed cases of SARS-CoV–2 infection. WHO (43) issued guidelines on breastfeeding in cases confirmed by SARS-CoV–2, highlighting the effectiveness of breastfeeding against infectious diseases, in addition to strengthening the newborn’s immune system. Therefore, he advised to maintain breastfeeding, with precautions related to transmission, recommending, still, washing hands frequently and wearing masks. The Centers for Disease control and Prevention(CDC)  the Brazilian Ministry of Health (MS) [10, 41–48]. NHS and Royal College of Obstetricians & Gynaecologists, advise breastfeeding with measures to prevent airborne transmission, as the available evidence is insufficient, and the benefits of breastfeeding outweigh the risk.
A study  does not recommend the separation of mother and child, nor contraindicated breastfeeding during the mother’s infection period. However, it stressed that transmission prevention measures must be rigorous, such as hand hygiene.