SARS-CoV-2 vaccine(The Scientific and Technological Research Council of Turkey)

Italian Ministry of Health recommended co-administration of influenza and SARS-CoV-2 vaccines for the 2023/2024 influenza season. Healthcare workers and students were identified as target categories for the vaccination campaign and the importance to implement pharmacovigilance programs was highlighted. We aimed to investigate the safety profile of mRNA SARS-CoV-2 vaccine (XBB.1.5), cell-based and egg-grown quadrivalent inactivated influenza vaccines (QIVc, QIVe) and the influence of co-administration on Adverse Events Following Immunization (AEFIs) via an active surveillance study. In this prospective observational cohort study, participants who received XBB.1.5, QIVc or QIVe, between October 17th-December 31st, 2023, either alone or in co-administration, were enrolled. AEFIs occurred in the first 7-days post-vaccination period were collected to investigate the reactogenicity profile of SARS-CoV-2 and influenza vaccines in co-administration or alone. 1014 HCWs completed the study follow-up. Of these, 34.12 % received co-administered influenza (QIVc or QIVe) and XBB.1.5 vaccine; 63.12 % either influenza vaccine alone (mostly QIVc) and only 2.8 % SARS-CoV-2 vaccine alone. The AEFIs reporting rate (RR) was 61.3/100 completed follow-ups (622/1014). The most-common AEFIs across all groups were injection site pain/itching and asthenia/malaise. Only 3 serious AEFIs occurred (RR0.30/100). Administration of XBB.1.5, either alone or co-administered with QIVe or QIVc, was associated with a higher risk of AEFIs (OR 4.82; 95 % CI 3.48-6.66; p < 0.001). Male sex was found to decrease the risk of AEFIs (OddsRatio 0.49; 95 %CI 0.37-0.65; p < 0.001). This study confirmed the safety profile of both SARS-CoV-2 and influenza vaccines, even when co-administered. However, healthcare authorities and policymakers should investigate HCWs concerns about SARS-CoV-2 vaccination and co-administration strategies.

SARS-CoV-2 mRNA-LNP immunizations significantly reduce severe coronavirus disease 2019 (COVID-19) disease and have been widely administered throughout the world including those who are pregnant and postpartum. However, our understanding of the immune response within the context of pregnancy and breastfeeding, especially the antibody kinetics and function within the breast milk compartment, is limited. To address this gap, we studied longitudinal blood and breast milk samples from lactating women throughout the primary immunization schedule and for several months after. The overarching goal of this study is to delineate the antibody kinetics, binding breadth, and neutralization capacity of SARS-CoV-2 mRNA-LNP vaccine-elicited antibodies within the breast milk compartment and compare to that in serum.

We enrolled 13 participants prior to receiving SARS-CoV-2 immunization. We measured anti-SARS-CoV-2 Spike IgG or IgA in serum and self-collected breast milk in participants over a 6-month period. Breast milk was processed by removing lipids and cellular debris by cold centrifugation, and skim milk was then filtered for binding antibody multiplexed assays and neutralization assays.

Postpartum immunization with a SARS-CoV-2 mRNA-LNP vaccine elicits a robust IgG response and moderate IgA response in serum, which is transferred to breast milk. Serum was able to neutralize pseudovirus after completion of the vaccine schedule. These responses persisted for several months predominantly in persons with a potential history of SARS-CoV-2 infection.

Immunization elicits persistent anti-SARS-CoV-2 breast milk antibody responses. We found that hybrid immune individuals had enhanced neutralization and anti-Spike IgG in breast milk and serum. The impact of breast milk antibody on infant anto-SARS-CoV-2 immune responses requires further study.