ABSTRACT
Background. COVID-19 reinfection is generally defined as having 2 positive SARS-CoV-2 tests greater than 90 days apart. The clinical implications and impact of COVID-19 reinfection are not completely understood. We evaluated clinical and demographic characteristics of patients with COVID-19 reinfection. Methods. All SARS-CoV-2 polymerase chain reaction (PCR) tests performed at Joint Base San Antonio (JBSA), from March 27, 2020 through January 19, 2022 were analyzed. COVID-19 reinfection was defined as having 2 positive PCR tests >90 days apart. Available data for comorbidities, travel, COVID-19 vaccination status, SARS-CoV-2 genotype, symptoms, hospitalization, and treatments were compared for first and second infections. Results. A total of 310,704 SARS-CoV-2 PCR tests performed of which 25,543 (8.2%) were positive at JBSA during the study period. Patients with COVID-19 reinfection (n=532;4.2%) were identified and 266 (50%) charts reviewed. The mean age was 36.5 (+/-15) years and approximately half were males and active duty members (Table 1). The median time from first to second infection was 326 days (IQR 160-385). Patients were predominantly unvaccinated (91.4%) at initial infection, however unvaccinated status was less common (40.2%) at second infection (40.2%;P<0.0001).A significantly higher proportion of patients were symptomatic at first infection (88.3%) compared to second infection (51.5%;P< 0.001). Pneumonia diagnosis was significantly higher (4.9% vs. 0.4%;P=0.0011) whereas hospitalization was similar (2.6% vs. 2.3%;P=0.0788) for first compared to second infection. Among hospitalized patients, critical illness was common for first infection (57.1%) but none of the patients were critically ill with their second infection. A third episode of infection was rarely observed (1.5%). Of 80 genotype samples available, 14 (30%) were paired samples. Among all paired samples different genotypes were responsible for reinfection (Table 2). Conclusion. Patients with COVID-19 reinfections were less likely to be symptomatic, had lower severity of illness, and typically had a different SARS-CoV-2 genotype at second infection. Reinfection occurred despite COVID-19 vaccination in many patients, which highlights the need to develop novel strategies for vaccination.
ABSTRACT
Background. Critically ill patients receiving extracorporeal membrane oxygenation (ECMO) are at elevated risk for nosocomial infection. Physiological responses to infection on ECMO are difficult to interpret as many clinical characteristics are controlled by the circuit including temperature. This study aimed to determine the culture positivity rates in patients receiving ECMO with influenza or COVID-19. Methods. A single center retrospective study was performed on all patients who received ECMO support at a single institution between December 2014 and December 2020 with influenza or COVID-19. All cultures ordered were reviewed for indication. Patients with fever without specific clinical syndrome or signs of decompensation, such as increasing vasopressor requirement were included. Infections and contaminants were defined by treatment team. Results. A total of 45 patients received ECMO with an admission diagnosis of influenza or COVID-19 during the study period. This cohort had a median age of 44 (interquartile range (IQR): 36-53) and was predominantly male (84%). The median time on ECMO was 360 hours (IQR: 183-666). 43/137 (31%) of infectious workups were ordered for isolated fever. The most common workup ordered for fever was combination blood cultures (BC) and urine cultures (UC) (13, 30%), followed by combination BC, UC, and respiratory cultures (RC) (11, 26%). Four (9%) infections were identified (3 blood stream, 1 respiratory) and five (12%) cultures grew contaminants (1 blood, 1 respiratory, 2 urine). Culture positivity rate was greatest for BC (3/35, 9%) followed by RC (1/19, 5%), and lowest for UC (0/26, 0%). Conclusion. Although cultures are commonly ordered for isolated fever in patients with influenza and COVID-19 receiving ECMO, culture positivity rate is low. In particular, no urinary tract infections were identified and the screening for urinary tract infection in patients receiving ECMO with isolated fever is not beneficial. Further work identifying signs and symptoms associated with infection is needed to improve diagnostic stewardship in this population that is high risk for nosocomial infections.