Neutralizing antibody activity against SARS-CoV-2 variants in gestational age-matched mother-infant dyads after infection or vaccination

Pregnancy confers unique immune responses to infection and vaccination across gestation. To date, there are limited data comparing vaccine- and infection-induced neutralizing Abs (nAbs) against COVID-19 variants in mothers during pregnancy. We analyzed paired maternal and cord plasma samples from 60 pregnant individuals. Thirty women vaccinated with mRNA vaccines (from December 2020 through August 2021) were matched with 30 naturally infected women (from March 2020 through January 2021) by gestational age of exposure. Neutralization activity against the 5 SARS-CoV-2 spike sequences was measured by a SARS-CoV-2-pseudotyped spike virion assay. Effective nAbs against SARS-CoV-2 were present in maternal and cord plasma after both infection and vaccination. Compared with WT spike protein, these nAbs were less effective against the Delta and Mu spike variants. Vaccination during the third trimester induced higher cord-nAb levels at delivery than did infection during the third trimester. In contrast, vaccine-induced nAb levels were lower at the time of delivery compared with infection during the first trimester. The transfer ratio (cord nAb level divided by maternal nAb level) was greatest in mothers vaccinated in the second trimester. SARS-CoV-2 vaccination or infection in pregnancy elicits effective nAbs with differing neutralization kinetics that are influenced by gestational time of exposure.

Passive and active immunity in infants born to mothers with SARS-CoV-2 infection during pregnancy: prospective cohort study

OBJECTIVE

To investigate maternal immunoglobulins' (IgM, IgG) response to SARS-CoV-2 infection during pregnancy and IgG transplacental transfer, to characterise neonatal antibody response to SARS-CoV-2 infection, and to longitudinally follow actively and passively acquired antibodies in infants.

DESIGN

A prospective observational study.

SETTING

Public healthcare system in Santa Clara County (California, USA).

PARTICIPANTS

Women with symptomatic or asymptomatic SARS-CoV-2 infection during pregnancy and their infants were enrolled between 15 April 2020 and 31 March 2021.

OUTCOMES

SARS-CoV-2 serology analyses in the cord and maternal blood at delivery and longitudinally in infant blood between birth and 28 weeks of life.

RESULTS

Of 145 mothers who tested positive for SARS-CoV-2 during pregnancy, 86 had symptomatic infections: 78 with mild-moderate symptoms, and 8 with severe-critical symptoms. The seropositivity rates of the mothers at delivery was 65% (95% CI 0.56% to 0.73%) and the cord blood was 58% (95% CI 0.49% to 0.66%). IgG levels significantly correlated between the maternal and cord blood (Rs=0.93, p<0.0001). IgG transplacental transfer ratio was significantly higher when the first maternal positive PCR was 60-180 days before delivery compared with <60 days (1.2 vs 0.6, p<0.0001). Infant IgG seroreversion rates over follow-up periods of 1-4, 5-12, and 13-28 weeks were 8% (4 of 48), 12% (3 of 25), and 38% (5 of 13), respectively. The IgG seropositivity in the infants was positively related to IgG levels in the cord blood and persisted up to 6 months of age. Two newborns showed seroconversion at 2 weeks of age with high levels of IgM and IgG, including one premature infant with confirmed intrapartum infection.

CONCLUSIONS

Maternal SARS-CoV-2 IgG is efficiently transferred across the placenta when infections occur more than 2 months before delivery. Maternally derived passive immunity may persist in infants up to 6 months of life. Neonates are capable of mounting a strong antibody response to perinatal SARS-CoV-2 infection.

Therapeutic Drug Monitoring of Antiepileptic Drugs at a Tertiary Care Hospital of Eastern Nepal

Background Therapeutic drug monitoring (TDM) is the process of measuring drug level in body fluids. It is done to maintain plasma concentration of the drug under therapy within a specific target range for maximum therapeutic efficacy without unnecessary exposure to adverse effects. Objective This study aims to evaluate necessity of therapeutic drug monitoring in Phenytoin, Carbamazepine and Lamotrigine therapy among epileptic patients. Method A prospective, cross-sectional study was conducted for a period of one year at BP Koirala Institute of Health Sciences, Dharan, Nepal. After taking detailed history, blood samples were collected from epileptic patients on monotherapy with the selected drugs. Plasma levels of these drugs were analyzed using High Performance Liquid Chromatography technique (HPLC). Out of total 42 selected patients, 21 were tested for phenytoin, 17 for carbamazepine and four for lamotrigine. The result was categorized into therapeutic, sub-therapeutic and above-therapeutic groups based on reference range. Result Out of total 21 samples tested for phenytoin, 15(71.4%) had plasma drug level within therapeutic range, 5(23.8%) had within subtherapeutic range and 1(4.8%) had above therapeutic range. Analysis of carbamazepine plasma level showed 14(82.3%) at therapeutic level, 1(5.9%) at sub-therapeutic level and 2(11.8%) at above-therapeutic level. Lamotrigine testing in four samples showed 2(50% in) both within therapeutic range and above-therapeutic range. Conclusion Therapeutic drug monitoring of phenytoin, carbamazepine and lamotrigine showed variation in plasma level irrespective of the therapeutic dose. It is suggested that dose adjustment of antiepileptic drugs should be done after establishing 'individual therapeutic range' following regular plasma monitoring.