Development of SARS-CoV-2 specific IgG and IgA antibodies in serum and milk with different SARS-COV-2 vaccines in lactating women.

BACKGROUND: Our main objective was to determine the evolution of IgG and IgA antibodies directed against SARS-CoV-2 protein S in the blood of lactating women and in breast milk. METHODS: A cohort of 110 uninfected and vaccinated breastfeeding women was followed-up for 6 months at the Marqués de Valdecilla University Hospital, Spain, in 2020. An additional group of 23 breastfeeding mothers who had no previously documented infection and had not been vaccinated against SARS-CoV-2 were included as a control group. The antibodies in blood and breast milk and their evolution at 6 months post-vaccination were analysed. RESULTS: One hundred ten breastfeeding mothers were included; 70 women (63.6%) were vaccinated with two doses of BNT162b2, 20 women (18.2%) received two doses of mRNA-1273, and 20 women (18.2%) received a single dose of ChAdOx1-S. No evidence of differences between concentrations of antibodies was found according to the type of vaccine, with the exception of serum IgA antibodies, which was higher in women vaccinated with mRNA-1273: mean [95%CI]: 0.05 AU/mL [0.03,0.06] with mRNA-1273, 0.02 AU/mL [0.01,0.03] with BNT162b2 and 0.01 AU/mL [0.00,0.03] with ChAdOx1-S, ANOVA p value = 0.03. The lack of difference between vaccines was also found when anti-S1 specific IgG in serum and breast milk were measured. CONCLUSIONS: In lactating women vaccinated against COVID-19, anti-SARS-CoV-2 antibodies can be detected in both serum and breastmilk 6 months after receiving the second dose, although their concentrations decreased when compared with concentrations reached immediately after vaccination.

Induction of SARS-CoV-2-Specific IgG and IgA in Serum and Milk with Different SARS-CoV-2 Vaccines in Breastfeeding Women: A Cross-Sectional Study in Northern Spain.

Breastfeeding mothers were excluded from the clinical trials conducted for vaccines against SARS-CoV-2. Since the start of the vaccination, some doubts have arisen regarding its compatibility with breastfeeding. The aim of this study was to analyse the presence of anti-SARS-CoV-2 antibodies in breast milk and serum (IgG and IgA) of vaccinated breastfeeding women. The main variables of the observational study were: adverse related events after vaccination and determination of the presence of IgG and IgA isotypes antibodies in serum and in breast milk of vaccinated women against the SARS-CoV-2 antigens. Results: 110 breastfeeding mothers were included; 70 women (63.6%) were vaccinated with two doses of BNT162b2, 20 women (18.2%) with two doses of mRNA-1273, and 20 women (18.2%) with a single dose of ChAdOx1-S. Regarding adverse reactions and vaccine safety, 38 women had no adverse reactions; 20 (18.2%) had general malaise or adenopathies; 10 (9.1%) had a headache; and 7 (6.4%) had fever. When analysing IgG antibodies, significantly higher levels of antibodies were found in serum and breast milk from mothers vaccinated with BNT162b2 or mRNA-1273 vs. ChAdOx1-S (p < 0.001 and p = 0.001, respectively). Analysing IgA antibodies, significant differences were found when comparing mean values in serum from mothers vaccinated with BNT162b2 or mRNA-1273 vs. ChAdOx1-S (0.12, 0.16, and 0.02, respectively; p < 0.001) and breast milk of mothers vaccinated when comparing BNT16b2 vs. ChAdOx1-S. All vaccinated breastfeeding mothers had serum anti-S1 IgG antibodies in response to vaccination against SARS-CoV-2, regardless of the commercial vaccine administered. Conclusions: the anti-SARS-CoV-2 vaccines were well tolerated by the mothers and the breastfed infant. In addition, breastfeeding mothers offer their infants IgA and IgG isotype antibodies directed against SARS-CoV-2 protein S in breast milk.

High prevalence of cryofibrinogenemia in patients with chilblains during the COVID-19 outbreak.

BACKGROUND: Many cutaneous manifestations have been described in possible association with the COVID-19 pandemic, including acral lesions resembling chilblains. The underlying pathomechanisms of COVID-19 chilblains are not fully understood. The aim of this study was to describe the clinical, pathological, and laboratory findings of a series of patients who developed chilblains during the COVID-19 outbreak and to investigate the possible factors that could be involved in the pathogenesis of these lesions. METHODS: We conducted a prospective cohort study that included 54 patients who presented with chilblains during the highest peak in the incidence of COVID-19 in Cantabria (northern Spain). Skin biopsies were performed on 10 of these patients who presented with recent lesions. Laboratory investigations, including immunological analysis, serological studies, and the assessment of cryoproteins, were also performed. RESULTS: Most patients presented erythematous plaques located on the toes and/or purpuric macules located on the feet. Histopathological findings were compatible with those of idiopathic chilblains. Immunohistochemical evaluation showed C3d and C4d deposits in the vessel walls in seven cases. The autoimmunity panel was negative in most of our series. Cryoprotein testing showed positive cryofibrinogen in two-thirds (66.7%) of the patients assessed. On follow-up, most patients presented almost complete resolution, although six patients required prednisone and antiaggregant drug treatment. CONCLUSIONS: This study shows, for the first time to our knowledge, a high prevalence of cryofibrinogenemia in patients with chilblains during the COVID-19 pandemic. Cryofibrinogenemia could be implicated in the pathogenesis of chilblains related to COVID-19.