Development and reproductive safety of AdCLD-CoV19, an adenoviral vector-based COVID-19 vaccine, in female Sprague-Dawley rats and their offspring.

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) resulted in over 180 million cases and 4 million deaths by mid-2021. Vaccine hesitancy, particularly among women, stems from limited safety data in vulnerable populations. Therefore, we evaluated the developmental and reproductive safety of AdCLD-CoV19, an adenoviral vector-based coronavirus 2019 (COVID-19) vaccine, in pregnant Sprague-Dawley rats and their offspring. Female rats received AdCLD-CoV19 (5 × 10¹⁰ viral particles/head/d, 0.5 mL intramuscularly) twice before mating, thrice during gestation, and once postnatally. We assessed general toxicity, fertility, embryo-fetal development, postnatal development, maternal function, and immunogenicity through embryo-fetal development and pre- and postnatal development studies. AdCLD-CoV19 produced no significant toxicological effects on fetuses or neonates. No treatment-related effects were observed in maternal animals or F1 offspring, including body weight, food consumption, fertility, developmental, or behavioral endpoints. No malformations were detected in fetuses or pups. Vaccinated dams and offspring exhibited significantly elevated anti-spike IgG titers, confirming effective maternal antibody transfer through placental and lactational routes. These findings support the safety profile of AdCLD-CoV19 in pregnant and lactating females. Further clinical studies are needed to confirm translational relevance in humans.