In a recent study published in Clinical microbiology and infectionresearchers evaluated the effect of vaccination against coronavirus 2 (SARS-CoV-2) on pregnant women during the Omicron wave.
During the coronavirus 2019 (COVID-19) pandemic, pregnant women were more likely than the general population to develop severe COVID-19. in the womb Mother-to-child transmission of the virus has been shown to be uncommon, and infected mothers showed a strong immune response with anti-SARS-CoV-2 antibodies that pass to their newborns.
Despite several studies reporting a significant maternal antibody response to SARS-CoV-2 immunization and the absence of safety issues, the vaccination rate among pregnant women remained lower than that of the general population. Few studies have been conducted so far on the impact of the SARS-CoV-2 Omicron variant on unvaccinated and vaccinated pregnant women.
In the current study, the researchers compared the perinatal and maternal outcomes of women infected with SARS-CoV-2 in Italy during the SARS-CoV-2 Omicron variant wave based on vaccination protection.
Current national prospective cohort research included pregnant women who tested positive for COVID-19 within seven days of hospital admission in any Italian maternity unit between January 1 and May 31, 2022. In addition, women reported whether they had received a SARS-CoV-vaccine. 2, as well as when (before and/or at the time of conception) and how many doses were received.
The primary outcome measure was the severity of SARS-CoV-2 disease, categorized as mild, moderate, or severe. The two most severe severity categories, defined by a diagnosis of pneumonia, were pooled together for statistical analysis as “moderate or severe COVID-19 disease” (MSCD). Secondary outcomes included preterm birth, stillbirth, mode of delivery, admission to the neonatal intensive care unit (NICU), and premature neonatal death before hospital release.
MSCD protection was considered as an exposure variable. Women who were vaccinated with at least one vaccine dose at the time of pregnancy, who were vaccinated with the full vaccine schedule and the first booster vaccine were protected against MS. On the other hand, unvaccinated women and participants who were vaccinated with one or two doses of the vaccine before pregnancy and tested positive for SARS-CoV-2 at 22 or more weeks of gestation were considered unprotected. Women with incomplete vaccination information and those who had been vaccinated with one or two doses before pregnancy and who tested positive for SARS-CoV-2 at less than 22 weeks of gestation were considered “unknown in terms of protective status”.
Between January 1 and May 31, 2022, a total of 2,774 women were recorded who tested positive for SARS-CoV-2 within seven days of hospitalization. Information was available on the protection status of 2147 women, while no significant clinical or sociodemographic differences were observed between these women and the entire cohort.
According to the study definition, 1069 (49.8%) individuals were protected from MS. Among them, 74 were vaccinated with a single vaccine during pregnancy, 596 received two vaccinations, including at least one dose during pregnancy, and 327 received their first booster dose. In contrast, 1078 unprotected women, including 989 unvaccinated women and 89 who tested positive for SARS-CoV-2 at 22 weeks or more of gestation after receiving one or two doses before pregnancy, were considered. All but 26 women were immunized with conventional immunizations alone or in combination with messenger ribonucleic acid (mRNA) vaccines.
Compared to protected women, unprotected women showed a greater likelihood of being younger, less educated, of foreign nationality, and of symptoms. Also, 96.4% were hospitalized for reasons related to labor or childbirth, while 3.6% were hospitalized due to the coronavirus. Eight of these had severe disease, 12 had moderate disease, and 58 had mild disease.
MS was generally uncommon but more prevalent among unprotected women than among protected women. Of the 41 MSCD cases, 27 of the 29 unprotected women had not received any vaccine, while two had been vaccinated with two doses before pregnancy. Three of the 12 protected women received a booster dose, while nine received two doses, of which the first was received before and the second during pregnancy.
Among unprotected women, seven out of eight cases of severe infection and one maternal death occurred. COVID-19 pneumonia was considered the cause of death, and it was reported two weeks after birth. Unprotected women had a greater incidence of MSCD than protected women, Asian women, and those with a history of comorbidities.
Sensitivity analysis revealed that unprotected women had a significantly higher risk of MSCD than protected women. Furthermore, 8.7% of newborns were born preterm, often in late parturition, with no significant differences between unprotected and protected women, but caesarean section was reported in 34.4% and 29.3% of women, respectively. The rate of preterm birth was greater among women with MSCD than among women with milder conditions and women with CS. Also, of the 619 CS cases, five were urgent/emergency cases due to COVID-19, and all involved women with MSCD.
Overall, the results of the study documented a significantly reduced prevalence of acute SARS-CoV-2 infection in pregnant women effectiveness The COVID-19 vaccine provides protection. These statistics can serve as the basis for informing pregnant women of uncertainty about vaccine efficacy and demonstrating the importance of vaccination in protecting newborns.