A Tale of Two Twins: Discordant Presentation of COVID-19 in Identical Twins

Abstract

Coronavirus disease 2019 (COVID-19) is a highly contagious viral illness caused by the RNA virus Coronaviridae subtype severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Rapid infection caused by this virus became overwhelming and resulted in millions of deaths worldwide. The effects of smoking have been heavily studied and lead to increased occurrence of COVID-19 viral infections and mortality. The phenomenon of cytokine storm has been shown as one of the leading factors of mortality. However, the question remains as to what factors, either genetic or environmental, ultimately lead to the increased incidence of cytokine storms compared to others. We present a case of two cohabitating, 57-year-old, male, identical twins (Twin A and Twin B) who contracted SARS-CoV-2 simultaneously. Both Twin A and Twin B had similar medical histories, except for Twin A being a former smoker while Twin B a current smoker. While both twins presented with cough and shortness of breath, Twin A also presented with hypoxia, leukocytosis, evidence of acute kidney injury, and transaminitis while Twin B presented normoxic with solely tachycardia. Due to his presentation and vital signs, Twin B received Bamlanivimab but developed hypoxia during the infusion. Both twins were subsequently initiated on Remdesivir, dexamethasone, and supplemental oxygen daily. After completion of treatment courses, both twins had improvement in their laboratory values and were subsequently discharged with supplemental oxygen to be further weaned in the outpatient setting. Due to the twins’ cohabitation, contracting SARS-CoV-2 simultaneously, and similar medical history, we highlight the potential mechanism of nicotine’s chemical ability to blunt the subsequent inflammatory process of COVID-19. Despite nicotine’s potential ability to dampen cytokine storms, smoking has well-documented adverse effects and we, like many experts, entirely discourage it. However, given the rare situation of identical twins contracting SARS-CoV-2, we can extrapolate information regarding the effects of the virus without obfuscation from genetic and environmental factors to identify areas of research for new therapies.

Genetics, shared environment, or individual experience? A cross-sectional study of the health status following SARS-CoV-2 infection in monozygotic and dizygotic twins

“…Our results predominantly show no statistically significant correlations between current complaints and limitations within twin pairs after SARS-CoV-2 infection. These findings are in line with recent case reports of MZ who showed very different disease courses in the context of COVID-19 ( 17 – 19 ).…”

“…Our results predominantly show no statistically significant correlations between current complaints and limitations within twin pairs after SARS-CoV-2 infection. These findings are in line with recent case reports of MZ who showed very different disease courses in the context of COVID-19 (17)(18)(19). Estimates of heritability (h 2 ), common (c 2 ), and individual environmental (e 2 ) effects on outcomes following SARS-CoV-2 infection according to Falconer's formula.…”

“…In line with our findings, current evidence suggests that smoking may worsen COVID-19 outcomes ( 39 , 48 , 49 ). However, a recent case report described a possible mechanism for nicotine to attenuate the subsequent inflammatory process of COVID-19 ( 19 ); this potential mechanism needs further investigation.…”

“…Overall, studies with adult twins on SARS-CoV-2 infection are scarce but have already highlighted the fact that there is a genetic component associated with the highly variable clinical outcomes of SARS-CoV-2 infection. Since the corona pandemic, there have been a few case reports of twins contracting the virus and the course of the disease (17)(18)(19). In a large twin study from the UK, a special app was used to investigate the heritability of clinical manifestations of acute SARS-CoV-2 infection.…”