When twin brothers in Italy developed similar Covid-19 symptoms, doctors expected the infection in both would follow similar clinical courses, but while one recovered relatively quickly, the other became critically ill and required an ICU stay—and doctors can't explain why, according to case study in the Annals of Internal Medicine.
The case study was described in a letter submitted to the journal, written by Davide Lazzeroni of Fondazione Don Carlo Gnocchi in Italy and his colleagues.
According to the case study, the twins—considered homozygous because of their physical appearance and shared characteristics—had a striking number of similarities beyond their shared genetic background. Both men, aged 60, lived at the same address and "worked at the same job in the same workplace," an auto shop.
Furthermore, the twins shared the same vaccination schedule and had similar diets. And both likely caught the virus from the same shop customer—meaning they "acquired the same virus"—and both had similar "viral load at diagnosis," the authors wrote.
Moreover, at the start, the disease seemed to take the same trajectory in both of them. After experiencing symptoms for 10 days, ranging from fever to a dry cough, the twins were both admitted to the hospital with mild interstitial pneumonia. While hospitalized, both received supplemental oxygen and experimental treatments, including paracetamol and hydroxychloroquine—and both receive these treatments from the same medical team, with the same level of dosages.
However, after 12 days at the hospital, one twin was discharged and soon recovered—while the other twin steadily declined. This latter twin was eventually transferred to the ICU for mechanical ventilation, where he soon "developed septic shock from an anaerobic bacterial infection that required vasopressors, antibiotics, steroids, and four days of invasive ventilation." Once released from the ICU, he remained in the hospital for another 17 days before he recovered sufficiently for discharge.