Project description:BackgroundThe SARS-CoV-2 omicron variant (B.1.1.529) is highly transmissible, but disease severity appears to be reduced compared with previous variants such as alpha and delta. We investigated the risk of severe outcomes following infection in residents of long-term care facilities.MethodsWe did a prospective cohort study in residents of long-term care facilities in England who were tested regularly for SARS-CoV-2 between Sept 1, 2021, and Feb 1, 2022, and who were participants of the VIVALDI study. Residents were eligible for inclusion if they had a positive PCR or lateral flow device test during the study period, which could be linked to a National Health Service (NHS) number, enabling linkage to hospital admissions and mortality datasets. PCR or lateral flow device test results were linked to national hospital admission and mortality records using the NHS-number-based pseudo-identifier. We compared the risk of hospital admission (within 14 days following a positive SARS-CoV-2 test) or death (within 28 days) in residents who had tested positive for SARS-CoV-2 in the period shortly before omicron emerged (delta-dominant) and in the omicron-dominant period, adjusting for age, sex, primary vaccine course, past infection, and booster vaccination. Variants were confirmed by sequencing or spike-gene status in a subset of samples.Results795 233 tests were done in 333 long-term care facilities, of which 159 084 (20·0%) could not be linked to a pseudo-identifier and 138 012 (17·4%) were done in residents. Eight residents had two episodes of infection (>28 days apart) and in these cases the second episode was excluded from the analysis. 2264 residents in 259 long-term care facilities (median age 84·5 years, IQR 77·9-90·0) were diagnosed with SARS-CoV-2, of whom 253 (11·2%) had a previous infection and 1468 (64·8%) had received a booster vaccination. About a third of participants were male. Risk of hospital admissions was markedly lower in the 1864 residents infected in the omicron-period (4·51%, 95% CI 3·65-5·55) than in the 400 residents infected in the pre-omicron period (10·50%, 7·87-13·94), as was risk of death (5·48% [4·52-6·64] vs 10·75% [8·09-14·22]). Adjusted hazard ratios (aHR) also indicated a reduction in hospital admissions (0·64, 95% CI 0·41-1·00; p=0·051) and mortality (aHR 0·68, 0·44-1·04; p=0·076) in the omicron versus the pre-omicron period. Findings were similar in residents with a confirmed variant.InterpretationObserved reduced severity of the omicron variant compared with previous variants suggests that the wave of omicron infections is unlikely to lead to a major surge in severe disease in long-term care facility populations with high levels of vaccine coverage or natural immunity. Continued surveillance in this vulnerable population is important to protect residents from infection and monitor the public health effect of emerging variants.FundingUK Department of Health and Social Care.
Project description:IntroductionElderly residents of nursing homes (NHs) and long-term care units (LTCUs) have been shown to have a high risk of mortality and morbidity in cases of SARS-CoV-2 infection. The objective of this study was to examine the kinetics of neutralizing antibodies (NAbs) directed against the SARS-CoV-2 virus in residents of the NH and LTCU units of our University Hospital who were identified with positive serology after the first epidemic outbreak.Materials and methodsThe participants included were sampled every three months for qualitative serological testing, as well as quantitative testing by neutralization tests using retroviral particles containing the S glycoprotein of SARS-CoV-2. Vaccination using the Comirnaty (Pfizer BNT162b2) vaccine begun before the last serological follow-up.ResultsThe median NAb titer in June 2020 was 80 [40; 60] versus 40 [40; 160] three months later, showing a statistically significant decline (p < 0.007), but remained stable between the three- and six-month timepoints (p = 0.867). By nine months after vaccination, we observed a significant difference between vaccinated residents known to have positive serology before vaccination (SERO+, Vacc+) and those vaccinated without having previously shown COVID-19 seroconversion (SERO-, Vacc+), the latter group showing similar titers to the SERO+, Vacc- participants (p=0.166). The median antibody titer in SERO+, Vacc+ patients increased 15-fold following vaccination.DiscussionHumoral immunity against SARS-CoV-2 appears to be persistent in elderly institutionalized patients, with a good post-vaccination response by residents who had already shown seroconversion but a notably diminished response by those who were seronegative before vaccination. To evaluate immunity in its entirety and elaborate a sound vaccination strategy, the cellular immune response via T cells specific to SARS-CoV-2 merits analysis, as this response is susceptible to being affected by immunosenescence.
Project description:BackgroundWastewater surveillance provided early indication of COVID-19 in US municipalities. Residents of long-term care facilities (LTCFs) experienced disproportionate morbidity and mortality early in the COVID-19 pandemic. We implemented LTCF building-level wastewater surveillance for SARS-CoV-2 at 6 facilities in Kentucky to provide early warning of SARS-CoV-2 in populations considered vulnerable.ObjectiveThis study aims to evaluate the performance of wastewater surveillance for SARS-CoV-2 at LTCFs in Kentucky.MethodsWe conducted a mixed methods evaluation of wastewater surveillance following Centers for Disease Control and Prevention (CDC) guidelines for evaluating public health surveillance systems. Evaluation steps in the CDC guidelines were engaging stakeholders, describing the surveillance system, focusing the evaluation design, gathering credible evidence, and generating conclusions and recommendations. We purposively recruited stakeholders for semistructured interviews and undertook thematic content analysis of interview data. We integrated wastewater, clinical testing, and process data to characterize or calculate 7 surveillance system performance attributes (simplicity, flexibility, data quality, sensitivity and positive predictive value [PPV], timeliness, representativeness, and stability).ResultsWe conducted 8 stakeholder interviews. The surveillance system collected wastewater samples (N=811) 2 to 4 times weekly at 6 LTCFs in Kentucky from March 2021 to February 2022. Synthesis of credible evidence indicated variable surveillance performance. Regarding simplicity, surveillance implementation required moderate human resource and technical capacity. Regarding flexibility, the system efficiently adjusted surveillance frequency and demonstrated the ability to detect additional pathogens of interest. Regarding data quality, software identified errors in wastewater sample metadata entry (110/3120, 3.53% of fields), technicians identified polymerase chain reaction data issues (140/7734, 1.81% of reactions), and staff entered all data corrections into a log. Regarding sensitivity and PPV, using routine LTCF SARS-CoV-2 clinical testing results as the gold standard, a wastewater SARS-CoV-2 signal of >0 RNA copies/mL was 30.6% (95% CI 24.4%-36.8%) sensitive and 79.7% (95% CI 76.4%-82.9%) specific for a positive clinical test at the LTCF. The PPV of the wastewater signal was 34.8% (95% CI 27.9%-41.7%) at >0 RNA copies/mL and increased to 75% (95% CI 60%-90%) at >250 copies/mL. Regarding timeliness, stakeholders received surveillance data 24 to 72 hours after sample collection, with delayed reporting because of the lack of weekend laboratory staff. Regarding representativeness, stakeholders identified challenges delineating the population contributing to LTCF wastewater because of visitors, unknown staff toileting habits, and the use of adult briefs by some residents preventing their waste from entering the sewer system. Regarding stability, the reoccurring cost to conduct 1 day of wastewater surveillance at 1 facility was approximately US $144.50, which included transportation, labor, and materials expenses.ConclusionsThe LTCF wastewater surveillance system demonstrated mixed performance per CDC criteria. Stakeholders found surveillance feasible and expressed optimism regarding its potential while also recognizing challenges in interpreting and acting on surveillance data.
Project description:BackgroundU.S. long-term care facilities have experienced a disproportionate burden of COVID-19 morbidity and mortality.MethodsWe examined SARS-CoV-2 transmission among residents and staff in 60 long-term care facilities in Fulton County, Georgia, from March 2020 to September 2021. Using the Wallinga-Teunis method to estimate the time-varying reproduction number, R(t), and linear mixed regression models, we examined associations between case characteristics and R(t).ResultsCase counts, outbreak size and duration, and R(t) declined rapidly and remained low after vaccines were first distributed to long-term care facilities in December 2020, despite increases in community incidence in summer 2021. Staff cases were more infectious than resident cases (average individual reproduction number, Ri = 0.6 [95%CI: 0.4-0.7] and 0.1 [95%CI: 0.1-0.2], respectively). Unvaccinated resident cases were more infectious than vaccinated resident cases (Ri = 0.5 [95%CI: 0.4-0.6] and 0.2 [95%CI: 0.0-0.8], respectively), but estimates were imprecise.ConclusionsCOVID-19 vaccines slowed transmission and contributed to reduced caseload in long-term care facilities. However, due to data limitations, we were unable to determine whether breakthrough vaccinated cases were less infectious than unvaccinated cases. Staff cases were six times more infectious than resident cases, consistent with the hypothesis that staff were the primary drivers of SARS-CoV-2 transmission in long-term care facilities.
Project description:ObjectivesOn November 5, 2021, Pfizer Inc. announced Paxlovid (nirmatrelvir +ritonavir) asa treatment method that could reduce the risk of hospitalization or death for patients withconfirmed coronavirus disease 2019 (COVID-19).MethodsFrom February 6, 2022 to April 2, 2022, the incidence of COVID-19 and the effectsof treatment with Paxlovid were analyzed in 2,241 patients and workers at 5 long-term carefacilities during the outbreak of the Omicron variant of severe acute respiratory syndromecoronavirus 2 in South Korea.ResultsThe rate of severe illness or death in the group given Paxlovid was 51% lower thanthat of the non-Paxlovid group (adjusted risk ratio [aRR], 0.49; 95% confidence interval [CI],0.24-0.98). Compared to unvaccinated patients, patients who had completed 3 doses of thevaccine had a 71% reduced rate of severe illness or death (aRR, 0.29; 95% CI, 0.13-0.64) and a65% reduced death rate (aRR, 0.35; 95% CI, 0.15-0.79).ConclusionPatients given Paxlovid showed a lower rate of severe illness or death and alower fatality rate than those who did not receive Paxlovid. Patients who received 3 dosesof the vaccine had a lower rate of severe illness or death and a lower fatality rate than theunvaccinated group.
Project description:BackgroundResidents of Long-Term Care Facilities (LTCFs) represent a major share of COVID-19 deaths worldwide. Measuring the vaccine effectiveness among the most vulnerable in these settings is essential to monitor and improve mitigation strategies.MethodsWe evaluate the early effect of the administration of BNT162b2-mRNA vaccine to individuals older than 64 years residing in LTCFs in Catalonia, Spain. We monitor all the SARS-CoV-2 documented infections and deaths among LTCFs residents once more than 70% of them were fully vaccinated (February-March 2021). We develop a modeling framework based on the relationship between community and LTCFs transmission during the pre-vaccination period (July-December 2020). We compute the total reduction in SARS-CoV-2 documented infections and deaths among residents of LTCFs over time, as well as the reduction in the detected transmission for all the LTCFs. We compare the true observations with the counterfactual predictions.ResultsWe estimate that once more than 70% of the LTCFs population are fully vaccinated, 74% (58-81%, 90% CI) of COVID-19 deaths and 75% (36-86%, 90% CI) of all expected documented infections among LTCFs residents are prevented. Further, detectable transmission among LTCFs residents is reduced up to 90% (76-93%, 90% CI) relative to that expected given transmission in the community.ConclusionsOur findings provide evidence that high-coverage vaccination is the most effective intervention to prevent SARS-CoV-2 transmission and death among LTCFs residents. Widespread vaccination could be a feasible avenue to control the COVID-19 pandemic conditional on key factors such as vaccine escape, roll out and coverage.
Project description:BackgroundOutbreaks of coronavirus disease (COVID-19) in hospitals and long-term care facilities (LTCFs) pose serious public health threats. We analysed how frequency and size of SARS-CoV-2 outbreaks in hospitals and LTCFs have altered since the beginning of the pandemic, in particular since the start of the vaccination campaign.MethodsWe used mandatory notification data on SARS-CoV-2 cases in Germany and stratified by outbreak cases in hospitals and LTCFs. German vaccination coverage data were analysed. We studied the association of the occurrence of SARS-CoV-2 outbreaks and outbreak cases with SARS-CoV-2 cases in Germany throughout the four pandemic waves. We built also counterfactual scenarios with the first pandemic wave as the baseline.FindingsBy 21 September 2021, there were 4,147,387 SARS-CoV-2 notified cases since March 2020. About 20% of these cases were reported as being related to an outbreak, with 1% of the cases in hospitals and 4% in LTCFs. The median number of outbreak cases in the different phases was smaller (≤5) in hospitals than in LTCFs (>10). In the first and second pandemic waves, we observed strong associations in both facility types between SARS-CoV-2 outbreak cases and total number of notified SARS-CoV-2 cases. However, during the third pandemic wave we observed a decline in outbreak cases in both facility types and only a weak association between outbreak cases and all cases.InterpretationThe vaccination campaign and non-pharmaceutical interventions have been able to protect vulnerable risk groups in hospitals and LTCFs.FundingNo specific funding.