Rate and severity of suspected SARS-Cov-2 reinfection in a cohort of PCR-positive COVID-19 patients

Abstract

Objectives To estimate the burden and severity of suspected reinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods A retrospective cohort of members of Kaiser Permanente Southern California with PCR-positive SARS-CoV-2 infection between 1st March 2020 and 31st October 2020 was followed through electronic health records for subsequent positive SARS-CoV-2 tests (suspected reinfection) ≥90 days after initial infection, through 31st January 2021. Incidence of suspected reinfection was estimated using the Kaplan–Meier method. Cox proportional hazards models estimated the association of suspected reinfection with demographic and clinical characteristics, hospitalization, and date of initial infection. Results The cohort of 75 149 was predominantly Hispanic (49 648/75 149, 66.1%) and included slightly more females than males (39 736, 52.9%), with few immunocompromised patients (953, 1.3%); 315 suspected reinfections were identified, with a cumulative incidence at 270 days of 0.8% (95% confidence interval (CI) 0.7–1.0%). Hospitalization was more common at suspected reinfection (36/315, 11.4%) than initial infection (4094/75 149, 5.4%). Suspected reinfection rates were higher in females (1.0%, CI 0.8–1.2% versus 0.7%, CI 0.5–0.9%, p 0.002) and immunocompromised patients (2.1%, CI 1.0–4.2% versus 0.8%, CI 0.7–1.0%, p 0.004), and lower in children than adults (0.2%, CI 0.1–0.4% versus 0.9%, CI 0.7–1.0%, p 0.023). Patients hospitalized at initial infection were more likely to have suspected reinfection (1.2%, CI 0.6–1.7% versus 0.8%, CI 0.7–1.0%, p 0.030), as were those with initial infections later in 2020 (150-day incidence 0.4%, CI 0.2–0.5% September–October versus 0.2%, CI 0.1–0.3% March–May and 0.3%, CI 0.2–0.3% June–August, p 0.008). In an adjusted Cox proportional hazards model, being female (hazard ratio (HR) 1.44, CI 1.14–1.81), adult (age 18–39, HR 2.71, CI 1.38–5.31, age 40–59 HR 2.22, CI 1.12–4.41, age ≥60 HR 2.52, CI 1.23–5.17 versus <18 years), immunocompromised (HR 2.48, CI 1.31–4.68), hospitalized (HR 1.60, CI 1.07–2.38), and initially infected later in 2020 (HR 2.26, CI 1.38–3.71 September–October versus March–May) were significant independent predictors of suspected reinfection. Conclusions Reinfection with SARS-CoV-2 is uncommon, with suspected reinfections more likely in women, adults, immunocompromised subjects, and those previously hospitalized for coronavirus 2019 (COVID-19). This suggests a need for continued precautions and vaccination in patients with COVID-19 to prevent reinfection.

Avidity of IgG to SARS-CoV-2 RBD as a Prognostic Factor for the Severity of COVID-19 Reinfection

“…In particular, the surveillance of healthcare workers in the U.K. [ 1 , 2 ] and Denmark [ 3 ], carried out in 2020 (i.e., before vaccinations began), showed that from 0.15% to 0.87% of patients who were seropositive after the initial COVID-19 infection were reinfected within about 6 months of follow-up. Similar data were obtained for a large cohort of patients (not at risk) in the USA [ 4 ]; approximately 0.8% had a new positive PCR test for SARS-CoV-2 within 270 days (but not before 90 days) after initial recovery. Furthermore, patients with reinfection were more likely to need hospital admission than patients with primary COVID-19 [ 4 ].…”

“…Similar data were obtained for a large cohort of patients (not at risk) in the USA [ 4 ]; approximately 0.8% had a new positive PCR test for SARS-CoV-2 within 270 days (but not before 90 days) after initial recovery. Furthermore, patients with reinfection were more likely to need hospital admission than patients with primary COVID-19 [ 4 ]. Among healthcare workers in Chicago, USA [ 5 ], up to 2.5% presented a probable reinfection within 6 months of follow-up.…”

“…The risk factors for reinfection and, more importantly, its outcome (i.e., the prognosis factors for the severity of recurrent disease) are still poorly understood [ 4 , 6 , 7 ]. It is reasonable to assume that the main risk factor for repeated infection is an insufficiently protective immunity.…”

Understanding the Effects of Age and T-Cell Differentiation on COVID-19 Severity: Implicating a Fas/FasL-mediated Feed-Forward Controller of T-Cell Differentiation

“…de Candia et al proposed that naive repertoires exert better control by virtue of greater TCR repertoire diversity which historically is associated with lower CD4 and CD8 T cell activation ( 38 ). however no model reconciles 1) the low Case Fatality Rate (CFR) seen in children ( 24 , 25 ); 2) the high CFR seen in the elderly ( 39 ); 3) cases of more severe reinfection ( 40 ); 4) the efficacy of steroids, which cause a rapid reduction in CD8+ T-cells, and suppress Fas and FasL in T-cells ( 41 – 45 ); 5) the efficacy of anti GM-CSF ( 46 , 47 ), which downregulates Fas expression on T-cells ( 48 ); and the high degree of Fas-mediated T cell apoptosis which characterizes severe Covid-19 ( 28 ).…”

Ofeleein i mi Vlaptin—Volume II: Immunity Following Infection or mRNA Vaccination, Drug Therapies and Non-Pharmacological Management at Post-Two Years SARS-CoV-2 Pandemic

“…Considering the reinfection of convalescent individuals, an Austrian retrospective study (n = 14,840) reported a relatively low reinfection rate (0.27%) among individuals with COVID-19 and deduced that protection against SARS-CoV-2 following a natural infection is comparable to the highest available estimates of vaccine efficacy [19]. Comparable results were also yielded by another retrospective study [20] from California with a sample size of n = 75,149, where the overall incidence of reinfection after 270 days was as low as 0.8%. Likewise, a prospective Italian study (n = 546) investigated reinfection rates of SARS-CoV-2 up to ten months post infection.…”