Abstract
As of September 2021, there has been a total of 123,633 confirmed cases of pregnant women with SARS-CoV-2 infection in the US according to the CDC, with maternal death being 2.85 times more likely, pre-eclampsia 1.33 times more likely, preterm birth 1.47 times more likely, still birth 2.84 times more likely, and NICU admission 4.89 times more likely when compared to pregnant women without COVID-19 infection. In our literature review, we have identified eight key changes in the immunological functioning of the pregnant body that may predispose the pregnant patient to both a greater susceptibility to SARS-CoV-2, as well as a more severe disease course. Factors that may impede immune clearance of SARS-CoV-2 include decreased levels of natural killer (NK) cells, Th1 CD4+ T cells, plasmacytoid dendritic cells (pDC), a decreased phagocytic index of neutrophil granulocytes and monocytes, as well as the immunomodulatory properties of progesterone, which is elevated in pregnancy. Factors that may exacerbate SARS-CoV-2 morbidity through hyperinflammatory states include increases in the complement system, which are linked to greater lung injury, as well as increases in TLR-1 and TLR-7, which are known to bind to the virus, leading to increased proinflammatory cytokines such as IL-6 and TNF-α, which are already elevated in normal pregnant physiology. Other considerations include an increase in angiotensin converting enzyme 2 (ACE2) in the maternal circulation, leading to increased viral binding on the host cell, as well as increased IL-6 and decreased regulatory T cells in pre-eclampsia. We also focus on how the Delta variant has had a concerning impact on SARS-CoV-2 cases in pregnancy, with an increased case volume and proportion of ICU admissions among the infected expecting mothers. We propose that the effects of the Delta variant are due to a combination of (1) the Delta variant itself being more transmissible, contagious, and efficient at infecting host cells, (2) initial evidence pointing to the Delta variant causing a significantly greater viral load that accumulates more rapidly in the respiratory system, (3) the pregnancy state being more susceptible to SARS-CoV-2 infection, as discussed in-depth, and (4) the lower rates of vaccination in pregnant women compared to the general population. In the face of continually evolving strains and the relatively low awareness of COVID-19 vaccination for pregnant women, it is imperative that we continue to push for global vaccine equity.
Highlights
In the context of pregnancy, since antenatal steroids are already routinely used for fetal lung maturity in preterm births [63], and with the potential benefit of decreased maternal mortality, the National Institutes of Health (NIH)’s COVID-19 Treatment Guidelines recommends a short course of dexamethasone for hospitalized pregnant patients who require supplemental oxygen, with or without mechanical ventilation [64]
The eight key changes that we have identified can be put into two categories: Factors that may impede immune clearance of SARS-CoV-2 include decreased levels of natural killer (NK) cells, Th1 CD4+ T cells, and plasmacytoid dendritic cells, a decreased phagocytic index of neutrophil granulocytes and monocytes, as well as the immunomodulatory properties of progesterone, which is elevated in pregnancy
Factors that may exacerbate SARS-CoV-2 morbidity through hyperinflammatory states include increases in the complement system, which are linked to greater lung injury, as well as increases in TLR-1 and TLR-7, known to bind to the virus, and leading to increased pro-inflammatory cytokines such as IL-6 and TNFα, which are already elevated in normal pregnant physiology
Summary
Ever since the lockdown of Wuhan on 23 February 2020 and the announcement of the global pandemic in March of 2020, the novel coronavirus has claimed over 5 million lives with over 245 million cases [1], and has greatly impacted every individual around the world in all facets of life, not just physically, and in terms of economic and social effects that may reverberate through generations to come This enveloped single-stranded RNA virus from the Coronaviridae family, named the severe acute respiratory syndrome coronavirus-2. Once the virus enters the host cell, it is able to replicate and is subsequently released from the host cell, causing pyrotosis (lytic programmed cell death) in the process This triggers the release of damage-associated molecular patterns (DAMPs) such as ATP and nucleic acids that go on to cause neighboring cells to initiate an inflammatory response. Protective anti-inflammatory factors such as neutralizing antibodies, type 1 interferons, IL-10, and regulatory T cell expansion are key in reaching the resolution stage [10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
