SARS-CoV-2 antibodies in breast milk of women given one & two doses of COVID-19 vaccine.

Background & objectives The COVID-19 pandemic underscores the significance of vaccination in mitigating disease spread, with Covishield and Covaxin serving as pivotal vaccines in India. Breast milk, rich in vital antibodies like IgA and IgG, plays a crucial role in enhancing the immune defence of breastfeeding infants. However, limited research exists on the antibody responses in breast milk among individuals receiving single versus double doses of the COVID-19 vaccine. This study aimed to bridge this gap by exploring IgA and IgG antibody levels in breast milk and assessing the correlation with COVID-19 vaccination status. Methods This hospital-based descriptive study aimed to assess the relationship between COVID-19 vaccination and the presence of anti-SARS-CoV-2 IgA/IgG antibodies in breast milk. Breast milk samples were collected using a sterile, closed-system electric breast pump and stored at -20°C. ELISA testing, utilizing commercially available kits, was utilized to assess anti-SARS-CoV-2 IgA and IgG antibodies. Results Among the 151 women participants, 76 (50.3%) received COVID-19 vaccination. Of these vaccinated women, 70 (92.1%) received Covishield, and 6 (7.9%) received Covaxin. Within the vaccinated cohort, 32 (42.1%) completed the recommended double-dose regimen, while 44 (57.9%) received a single dose. While no significant association was found between vaccination status and IgA positivity (P=0.491), a notable association emerged for IgG positivity (P<0.001). Notably, individuals who completed the recommended double-dose regimen exhibited higher IgA (63.6%) and IgG (65.4%) positivity compared to those receiving a single dose. Interpretation & conclusions This study underscores the significance of COVID-19 vaccination in impacting IgA and IgG antibody presence in breast milk. Completing the double-dose regimen correlated with higher IgA and IgG levels, emphasizing the benefits of complete vaccination. These findings contribute to understanding vaccination's impact on maternal-infant health.