Letter to the editor on use of antibodies from convalescent sera in the treatment of moderate and severe Covid-19 infection.

Convalescent plasma (CP) is a form of passive immunization that is used for disease prevention by transferring specific antibodies from a recovered patient to another patient with the same infection. It has been studied in the treatment of several viral infections with major conflicting results, including the Ebola virus, SARS-CoV1, and MERS-CoV. More recently, CP usage has been studied widely in the treatment of SARS-CoV2. Similar to previous studies in different outbreaks, the results have been inconsistent. In the recovery and CONCOR-1 trials, there was no difference in mortality nor clinical status at day 28 after CP infusion. On the other hand, Joyner et al. and Libster et al. showed that early infusion of high-titer CP may help in preventing clinical deterioration in mild Covid19 infection. Early in the pandemic and due to limited available therapeutic options for Covid-19 infection in Lebanon, we elected to study the efficacy of high-titer CP in moderate Covid-19 infections. A prospective and retrospective cohort study was conducted at the American University of Beirut Medical Center (AUBMC) over 14 months. It included all patients above 18 years presenting to AUBMC for moderate to severe Covid-19 infection. We excluded pregnant women and patients with a predicted survival of less than 2 days. Patients who received CP treatment (cases) in addition to standard therapy were compared to those who received standard therapy alone. The medical records for patients in both groups were reviewed and data related to demographics, medical comorbidities, symptoms upon presentation, the severity of infection on admission, laboratory findings, and treatment received were extracted. The clinical progress and laboratory data were recorded before and after receiving CP. Data were entered into a database using SPSS 29.0 (SPSS Inc, Chicago, IL). Bivariable analysis was conducted to examine the association between demographic and clinical variables with various outcome measures. The chi-square test and the independent samples t-test were used for categorical and continuous variables, respectively. A p-value of less than .05 was considered significant. We included 23 patients who received CP as cases and 46 patients as controls. Themean age in the cases group (63.4 ± 13.1 years) was more than that in the control group (60.5 ± 15.6). 52% of each group were males and 48% were females. The two groups had no significant difference in baseline demographics and medical comorbidities. Regarding the other Covid-19-related therapeutic options, corticosteroidsweremore