Persistence of Neutralizing Antibodies and Clinical Protection up to 12†Months After Severe Acute Respiratory Syndrome Coronavirus 2 Infection in the Elderly.

Background: Coronavirus disease 2019 (COVID-19) has severely affected the elderly, who are expected to display decreased immune responses due to immunosenescence. Methods: This study retrospectively assesses neutralizing antibody (NAb) production up to 12 months after infection in long-term care patients. We used Roche Diagnostics immunoassay to quantify anti-spike (S) antibodies and a competitive immunoassay from YHLO as a surrogate test for NAb. Results: We included 91 patients (mean age, 86 years). There was no significant variation in anti-S titers over time. There was a significant decrease of NAb titers between month 3 and month 6 but no further significant change up to month 12. Overall, 75 of 91 (82%) and 52 of 91 (57%) patients had, at least once, anti-S titers >75 U/mL and NAb titers >50 AU/mL, respectively, corresponding to a significant neutralizing activity in vitro. All 68 patients studied at M12 had detectable anti-S antibodies and 60 (88%) had detectable NAb; 60 of 68 (88%) and 29 of 68 (42.6%) still had anti-S titers >75 U/mL and NAb titers >50 AU/mL. Higher NAb titers were correlated with severe infection, higher levels of C-reactive protein, and lower lymphocyte counts. No patient developed reinfection. Conclusions: Elderly people can display robust and persistent humoral response after severe acute respiratory syndrome coronavirus 2 infection, with NAb lasting up to 12 months.

Chronology of COVID-19 Symptoms in Very Old Patients: Study of a Hospital Outbreak.

BACKGROUND: We wanted to better understand the frequency and temporal distribution of symptoms of COVID-19 in very old patients, which are currently not well defined. METHODS: In an observational, descriptive study, we followed all patients being at three geriatric convalescence and rehabilitation units when a COVID-19 outbreak emerged in those units in March 2020. For those who developed the disease, we recorded any new symptom occurring at diagnosis, in the previous 14 and the following 21 days. A group of SARS-Cov-2-negative patients served as controls. RESULTS: Sixty-nine of the 176 inpatients (mean age: 86 years) were infected by SARS-Cov-2 during the outbreak. At the moment of diagnosis, a majority of patients had fever (71.0%), malaise-asthenia (24.6%), or respiratory symptoms (66.7%). However, 48 patients (69.6% of all SARS-Cov-2 positive patients) also presented, usually several days before, other symptoms: (a) gastrointestinal symptoms (39.1% of all patients, median onset eight days before diagnosis, IQR -9 to +3 days); (b) neurological symptoms (30.4% of all patients, median onset five days before diagnosis, IQR -11 to -3 days), notably delirium (24.6%); and (c) other symptoms, like falls and unexplained decompensation of chronic conditions (29.0% of all patients, median onset four days before diagnosis, IQR -10 to 0). None of those symptoms were observed in similar proportion in 25 control SARS-CoV-2-negative patients, hospitalized during the same period. CONCLUSIONS: Diarrhea, nausea-vomiting, delirium, falls, and unexplained decompensation of chronic conditions were the first symptoms of COVID-19 in a majority of older patients in this cohort, preceding typical symptoms by several days. Recognizing those early symptoms could hasten the diagnosis of COVID-19 in this population.