Efficiency of Diagnostic Test for SARS-CoV-2 in a Nursing Home.

BACKGROUND: there is no consensus on how to optimally use diagnostic tests in each stage of COVID-19 pandemic. The objective of this research is to determine the efficiency of sorting positive antibody test quarterly. METHODS: this research uses a retrospective, observational study. COVID-19 diagnostic tests performed and avoided refer to a Spanish nursing home. POPULATION: 261 employees and 107 residents. A quarterly antibody test was performed on subjects who had tested positive during the first wave of coronavirus, and a antibody rapid test on the remaining subjects. RESULTS: during the first wave, 24.0% of the employees and 51.4% of the residents had a positive antibody test. Seronegativization was observed in 7.6% of employees and 1.6% of residents. An employee was infected with COVID-19 in September 2020, followed by a nursing home outbreak in October: 118 Polymerase Chain Reactions tests were avoided in residents and 18 in employees, which in turn prevented 15 workers from going on sick leave and the quarantine of 59 residents. This represents savings of about $15,000. CONCLUSIONS: our study supports the need to know and apply the strategies for early detection, surveillance and control of COVID-19 for future outbreaks. We conclude that surveillance for positive COVID-19 serology among long-term care staff and residents may be a cost-effective strategy during a pandemic.

Immunogenicity after 6 months of BNT162b2 vaccination in frail or disabled nursing home residents: The COVID-A Study.

BACKGROUND: There is incomplete information regarding evolution of antibody titers against SARS-CoV-2 after a two-dose strategy vaccination with BNT162b2 in older adults in long-term care facilities (LTCFs) with frailty, disability, or cognitive impairment. We aimed to determine IgG antibody titer loss in older adults in LTCFs. METHODS: This is a multicenter longitudinal cohort study including 127 residents (90 females and 37 males) with a mean age of 82.7 years (range 65-99) with different frailty and disability profiles in two LTCFs in Albacete, Spain. Residents received two doses of BNT162b2 as per label, and antibody levels were determined 1 and 6 months after the second dose. Age, sex, previous history of coronavirus disease 2019 (COVID-19), comorbidity (Charlson Index), performance in activities of daily living (Barthel Index), frailty (FRAIL instrument), and cognitive status were assessed. RESULTS: The mean antibody titers 1 and 6 months after the second vaccine dose were 32,145 AU/ml (SD 41,206) and 6182 AU/ml (SD 13,316), respectively. Across all participants, the median antibody titer loss measured 77.6% (interquartile range [IQR] 23.8%). Notably, the decline of titers in individuals with pre-vaccination COVID-19 infection was significantly lower than in those without a history of SARS-CoV-2 infection (72.2% vs. 85.3%; p < 0.001). The median titer decrease per follow-up day was 0.47% (IQR 0.14%) and only pre-vaccination COVID-19 was associated with lower rate of antibody decline at 6 months (hazard ratio 0.17; 95% confidence interval 0.07-0.41; p < 0.001). Frailty, disability, older age, cognitive impairment, or comorbidity were not associated with the extent of antibody loss. CONCLUSIONS: Older adults in LTCFs experience a rapid loss of antibodies over the first 6 months after the second dose of BNT162b2 vaccine. Only pre-vaccination COVID-19 is associated with a slower rate of antibody decrease. Our data support immunization with a third dose in this vulnerable, high-risk population.

Immunogenicity of the BNT162b2 vaccine in frail or disabled nursing home residents: COVID-A study.

BACKGROUND/OBJECTIVES: The safety and immunogenicity of the BNT162b2 coronavirus disease 2019 (COVID-19) vaccine in older adults with different frailty and disability profiles have not been well determined. Our objective was to analyze immunogenicity of the BNT162b2 mRNA COVID-19 vaccine in older adults across frailty and disability profiles. DESIGN: Multicenter longitudinal cohort study. SETTING AND PARTICIPANTS: A total of 134 residents aged ≥65 years with different frailty and disability profiles in five long-term care facilities (LTCFs) in Albacete, Spain. INTERVENTION AND MEASUREMENTS: Residents were administered two vaccine doses as per the label, and antibody levels were determined 21.9 days (SD 9.3) after both the first and second dose. Functional variables were assessed using activities of daily living (Barthel Index), and frailty status was determined with the FRAIL instrument. Cognitive status and comorbidity were also evaluated. RESULTS: Mean age was 82.9 years (range 65-99), and 71.6% were female. The mean antibody titers in residents with and without previous COVID-19 infection were 49,878 AU/ml and 15,274 AU/ml, respectively (mean difference 34,604; 95% confidence interval [CI]: 27,699-41,509). No severe adverse reactions were observed, after either vaccine dose. Those with prevaccination COVID-19 had an increased antibody level after the vaccine (B = 31,337; 95% CI: 22,725-39,950; p < 0.001). Frailty, disability, older age, sex, cognitive impairment, or comorbidities were not associated with different antibody titers. CONCLUSIONS: The BNT162b2 mRNA COVID-19 vaccine in older adults is safe and produces immunogenicity, independently of the frailty and disability profiles. Older adults in LTCFs should receive a COVID-19 vaccine.