The plates were then read with CLARIOstar? microtiter plate reader (Ortenberg, Germany) at an optical denseness of 450?nm. in the mothers in instances of delivery after 20?d of the second dose (1419??699 vs 1222??593 BAU/L; p?IL1A antibodies, COVID-19, heterologous prime-boost, immunogenicity, inactivated, newborn, pregnancy, SARS-CoV-2, spike protein, vaccine Intro As already known, pregnant women are at a greater risk of COVID-19 with more severity,1C5 and the possibility of maternalCfetal transmission of the disease is definitely of concern. Consequently, vaccination of pregnant women is essential to reduce the burden of the AG-490 disease for mothers and their babies.6 Various types of COVID-19 vaccines have been globally authorized for use in several countries, including whole-cell inactivated vaccines, mRNA vaccines, adenoviral-vectored vaccines, and subunit protein vaccines.7 In Thailand, the heterologous CoronaVac (Sinovac)CChAdOx1 (OxfordCAstraZeneca) is one of the desired vaccine regimens and is recommended by the National Vaccine Committee. The heterologous routine was first developed in response to the SARS-CoV-2 Delta variant, which partially escaped the vaccine-induced immunity provided by two doses of vaccination with CoronaVac.8 Subsequently, Wanlapakorn et al.9 showed that antibody levels and neutralizing activities against wild-type and variants of concern after two doses of the heterologous CoronaVacCChAdOx1 were higher, when compared to homologous CoronaVacCCoronaVac and heterologous ChAdOx1-CoronaVac organizations. Additionally, the spike-specific IgA response was recognized only in the heterologous CoronaVacCChAdOx1 group after two doses of vaccination. Given the shorter completion time of the two doses, heterologous CoronaVacCChAdOx1 can be considered as an alternative routine to homologous ChAdOx1-S. It is sensible to hypothesize the heterologous CoronaVacCChAdOx1 regimen can also induce higher antibody levels in pregnant women, though the assessment has not been tested in pregnancy. It is well established that in pregnant women with seropositive SARS-CoV-2 illness, IgG antibodies naturally derived from illness can be transferred across the placenta to the newborns.10,11 Placental transfer of antibody seems to be safe for any fetus or newborn, whether it is maternally derived by SARS-CoV-2 infection or vaccination.12C15 Accordingly, we ought to take advantage of the vaccination of mothers to protect their newborns after birth. AG-490 However, the effectiveness of such safety has not been completely evaluated. A very limited number of studies have been reported and most are limited to mRNA vaccines.10,16C19 Additionally, several issues remain to be elucidated, concerning the magnitude of the transferred antibody, the duration of the protective effects, the optimal interval for vaccination during pregnancy, and the forms of vaccines. To the best of our knowledge, heterologous CoronaVacCChAdOx1offers has never been evaluated, in terms of placental transfer of safety to newborns. Since non-mRNA vaccines are still generally used in many low-income and middle-income countries, and several women in high-income countries prefer non-mRNA vaccines, we carried out this study to evaluate the effectiveness of transplacental transfer of maternally derived SARS-CoV-2 IgG antibodies to provide neonatal safety from SARS-CoV-2 illness. Individuals and methods Study design and human population A prospective experimental study, single-arm non-randomized open clinical trial, authorized to Thai Clinical Tests Registry; TCTR20220125004, was carried AG-490 out on pregnant women attending antenatal care medical center at Maharaj Nakorn Chiang Mai hospital, a tertiary center and teaching school, and the Research Institute for Health Sciences, Chiang Mai University or college, from August 2021 to December 2021. All procedures including human participants were conducted in accordance with the Declaration of Helsinki AG-490 of 1975. The study protocol was ethically authorized by the Institutional Review Table, Faculty of Medicine (Research ID: 08376), Chiang Mai University or college. Women meeting the inclusion criteria were invited to participate in the study and provided with written educated consent prior to collecting medical data and blood samples. The inclusion criteria are as follows: (1) a healthy immunocompetent pregnant female at the age of 18?y or greater; (2) singleton pregnancy; (3) gestation of greater than 14?weeks; (4) no structural or chromosomal fetal abnormality; (5) known pregnancy results; and (6) bad test (RT-PCR) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) illness. The exclusion criteria are as follows: (1) delivery before 28?weeks of gestation; (2).