scholarly journals Outbreak of SARS-CoV-2 B.1.617.2 (Delta) variant in a Nursing Home 28 weeks after two doses of mRNA anti-Covid-19 vaccines: evidence of a waning immunity

Author(s):  
Alice Pierobon ◽  
Alessandra Dal Zotto ◽  
Antonio Antico ◽  
Mario Ernesto De Antoni ◽  
Liviano Vianello ◽  
...  

Objectives: Description of a SARS-CoV-2 B.1.617.2 (Delta) variant outbreak among residents (N = 69) and Health Workers (HWs: N = 69) of a small Nursing Home in Northern-East Italy, with full vaccination coverage of 91 and 82 %, respectively. Evaluation of the Anti-Spike IgG titers 28 weeks after the mRNA vaccine boosts against SARS-COV-2 infection and severe Covid-19. Materials and methods: A timely collection of sera within 48 h from the index case; anti-Spike IgG determination (expressed as Binding Antibody Units - BAU/mL) through a commercial quantitative assay; SARS-CoV-2 diagnostics via RT-PCR, and full-genome sequencing for lineage characterization. Residents were grouped according to anti-Spike IgG titers (≤50, 51-1000, and >1000 BAU/mL) and resulting protection against the infection and the severe disease was measured. Results: 0/20 HWs and 14/59 (24 %) residents fully vaccinated and without a previous SARS-CoV-2 infection showed anti-Spike IgG ≤50 BAU/mL (1-sided Fisher exact p=0.011). Among these residents, a level of anti-Spike IgG ≤50 BAU/mL resulted in a higher risk of SARS-CoV-2 infection (RR=1.55, CI 95% 1.17-2.05) and severe Covid-19 disease (RR=5.33, CI95% 1.83-15.57). Conclusion Low levels of SARS-CoV-2 neutralizing anti-Spike IgG in serum 28 weeks after the administration of the second dose parallels the waning of vaccine protection.

Author(s):  
Jean Bousquet ◽  
Hubert Blain ◽  
Edouard Tuaillon ◽  
Lucie Gamon ◽  
Amandine Pisoni ◽  
...  

Methods: Twenty-two French nursing homes were included. COVID-19 had been diagnosed with real-time reverse-transcriptase polymerase chain reaction (RT-PCR) for SARS-CoV-2. Blood S-protein IgG and nucleocapsid (N) IgG protein (N-protein IgG) were measured 21-24 days after the first jab (1,004 residents) and 6 weeks after the second (820 residents). Results: Among the 735 residents without prior COVID-19, 41.7% remained seronegative for S-protein IgG after the first jab vs 2.1% of the 270 residents with a previous positive RT-PCR (p<0.001). After the second jab, only 3% of the 586 residents without prior COVID-19 remained seronegative. However, 26.5% of them had low S-protein IgG levels (50-1050 UA/mL) vs 6.4% of the 222 residents with prior COVID-19. Residents with old infection (first wave), or seropositive for N-protein IgG at the time of vaccination, had the highest S-protein IgG levels. Residents with a prior COVID-19 infection had higher S-protein IgG levels after one dose than those without two jabs. Interpretation: A single vaccine jab is sufficient to reach immunity in residents with prior COVID-19. Most residents without prior COVID-19 are seropositive for S-protein IgG after the second jab, but around 30% have low levels of S-protein IgG. Whether residents with no or low post-vaccine immunity are at higher risk of symptomatic COVID-19 requires further analysis.


2021 ◽  
Vol 60 (4-5) ◽  
pp. 247-251
Author(s):  
Ameer Hassoun ◽  
Nessy Dahan ◽  
Christopher Kelly

The emergence of novel coronavirus disease-2019 poses an unprecedented challenge to pediatricians. While the majority of children experience mild disease, initial case reports on young infants are conflicting. We present a case series of 8 hospitalized infants 60 days of age or younger with coronavirus disease-2019. A quarter of these patients had coinfections (viral or bacterial). None of these infants had severe disease. Continued vigilance in testing this vulnerable group of infants is warranted.


2021 ◽  
pp. oemed-2020-106903
Author(s):  
Julio González Martin-Moro ◽  
Marta Chamorro Gómez ◽  
Galicia Dávila Fernández ◽  
Ana Elices Apellaniz ◽  
Ana Fernández Hortelano ◽  
...  

ObjectivesReverse transcriptase PCR (RT-PCR) is considered the gold standard in diagnosing COVID-19. Infected healthcare workers do not go back to work until RT-PCR has demonstrated that the virus is no longer present in the upper respiratory tract. The aim of this study is to determine the most efficient time to perform RT-PCR prior to healthcare workers’ reincorporation.Materials and methodsThis is a cohort study of healthcare workers with RT-PCR-confirmed COVID-19. Data were collected using the medical charts of healthcare workers and completed with a telephone interview. Kaplan-Meier curves were used to determine the influence of several variables on the time to RT-PCR negativisation. The impact of the variables on survival was assessed using the Breslow test. A Cox regression model was developed including the associated variables.Results159 subjects with a positive RT-PCR out of 374 workers with suspected COVID-19 were included. The median time to negativisation was 25 days from symptom onset (IQR 20–35 days). Presence of IgG, dyspnoea, cough and throat pain were associated with significant longer time to negativisation. Cox logistic regression was used to adjust for confounding variables. Only dyspnoea and cough remained in the model as significant determinants of prolonged negativisation time. Adjusted HRs were 0.68 (0.48–096) for dyspnoea and 0.61 (0.42–0.88) for dry cough.ConclusionsRT-PCR during the first 3 weeks leads to a high percentage of positive results. In the presence of respiratory symptoms, negativisation took nearly 1 week more. Those who developed antibodies needed longer time to negativisate.


Author(s):  
Clinton R Paden ◽  
Ying Tao ◽  
Krista Queen ◽  
Jing Zhang ◽  
Yan Li ◽  
...  

AbstractSARS-CoV-2 recently emerged, resulting a global pandemic. Rapid genomic information is critical to understanding transmission and pathogenesis. Here, we describe validated protocols for generating high-quality full-length genomes from primary samples. The first employs multiplex RT-PCR followed by MinION or MiSeq sequencing. The second uses singleplex, nested RT-PCR and Sanger sequencing.


2021 ◽  
Vol 12 ◽  
Author(s):  
Augusta Ortolan ◽  
Mariagrazia Lorenzin ◽  
Chiara Cosma ◽  
Giacomo Cozzi ◽  
Andrea Padoan ◽  
...  

ObjectiveSerology could help to define the real extent of SARS-CoV-2 diffusion, especially in individuals considered at higher risk of COVID-19, such as spondyloarthritis (SpA) patients undergoing immunosuppressant. Our aim was to detect, by serology, previous SARS-CoV-2 contact in SpA, compared to health care workers (HCW), and healthy controls.MethodsSera from consecutive patients affected by SpA undergoing cytokine-targeted therapy, HCW and healthy controls from 2015 were analysed through chemiluminescent analytical system for the presence of IgG and IgM anti-SARS-CoV-2. Positive patients (IgM or IgG, or both) additionally underwent real-time Polymerase-Chain-Reaction (RT-PCR) to test for active infection. Serology was repeated at 3-months in SpA. Data across 3 groups were compared by Kruskal Wallis/Chi-square, and between 2 groups by Wilcoxon rank test/Chi-Square. P ≤ 0.05 were considered significant.Results200 SpA, 95 HCW and 101 controls were recruited. Positive serology was found in 25(12.5%) SpA, 8(8.4%) HCW, 0(0%) controls (p=0.001). SpA patients with positive serology more frequently reported COVID-19-like symptoms than those with negative serology (20% vs. 4%, p=0.009) and 2 had COVID-19 as confirmed by RT-PCR, non severe. No HCW reported symptoms or had positive RT-PCR. In SpA patients, at 3 months, mean IgM titres decreased from 2.76 ± 2.93 to 2.38 ± 2.95 (p=0.001), while IgG titres from 0.89 ± 3.25 to 0.31 ± 0.87 (p=ns).ConclusionsSerology revealed that exposure to SARS-CoV-2 in SpA patients and HCW was higher than expected based on reported symptoms. In SpA, anti-cytokine therapy could act as a protective factor for a severe disease course. However, a seroconversion was not observed at 3-months.


2021 ◽  
Author(s):  
Billy J Gardner ◽  
A. Marm Kilpatrick

Background Vaccines have greatly reduced the impact of COVID-19 globally. Unfortunately, evidence indicates that immunity wanes following vaccination, especially with the Delta variant (B.1.617.2). Protection against severe disease and death remain high, but protection against milder disease and infection have dropped significantly. A third booster dose of two-dose vaccines has been approved in several countries to individuals at higher risk of severe disease to protect those individuals, but the benefit to boosting immunity in younger healthy individuals and the effects on transmission are less clear. Methods Here we use relationships between neutralizing antibody titers and vaccine protection against infection and transmission, combined with data on waning and boosting of neutralizing antibody titers to examine the impact of a third dose of the Pfizer vaccine on infection and transmission and its impact on the pathogen effective reproductive number Rt. Findings Eight months of waning reduced protection of the Pfizer vaccine against all infections from 80.0% (95% CI: 77% to 83%) to 60.4% (95% CI: 53% to 67%); a third dose (which increased neutralizing antibody titers 25.9- fold relative to levels after 8 months of waning) increased protection to 87.2% (95% CI: 83% to 91%). Increased protection against infection and transmission from third doses reduced Rt by 21% to 66% depending on vaccine coverage and previous infection and reduced Rt below 1 when vaccination coverage was high or contact rates were well below pre-pandemic levels. Interpretation A third dose of the Pfizer vaccine could reduce transmission of SARS-CoV-2, which would reduce infection in unvaccinated individuals and breakthrough infections in vaccinated individuals. While vaccination of unvaccinated individuals, especially in developing countries, would be more effective for reducing disease than providing a third dose to vaccinated individuals, the benefit of a third dose in reducing transmission is sizeable and increases with vaccine coverage and contact rates among individuals.


2021 ◽  
Author(s):  
Danuta M Skowronski ◽  
Solmaz Setayeshgar ◽  
Macy Zou ◽  
Natalie Prystajecky ◽  
John R Tyson ◽  
...  

Introduction: Randomized-controlled trials of mRNA vaccine protection against SARS-CoV-2 included relatively few elderly participants. We assess singe-dose mRNA vaccine effectiveness (VE) in adults ≥70-years-old in British Columbia (BC), Canada where the second dose was deferred by up to 16 weeks and where a spring 2021 wave uniquely included co-dominant circulation of B.1.1.7 and P.1 variants of concern (VOC). Methods: Analyses included community-dwelling adults ≥70-years-old with specimen collection between April 4 (epidemiological week 14) and May 1 (week 17). Adjusted VE was estimated by test-negative design through provincial laboratory and immunization data linkage. Cases were RT-PCR test-positive for SARS-CoV-2 and controls were test-negative. Vaccine status was defined by receipt of a single-dose ≥21 days before specimen collection, but a range of intervals was assessed. In variant-specific analyses, test-positive cases were restricted to those genetically-characterized as B.1.1.7, P.1 or non-VOC. Results: VE analyses included 16,993 specimens: 1,226 (7.2%) test-positive cases and 15,767 test-negative controls. Of 1,131 (92%) viruses genetically categorized, 509 (45%), 314 (28%) and 276 (24%) were B.1.1.7, P.1 and non-VOC lineages, respectively. VE was negligible at 14% (95% CI 0-26) during the period 0-13 days post-vaccination but increased from 43% (95% CI 30-53) at 14-20 days to 75% (95% CI 63-83) at 35-41 days post-vaccination. VE at ≥21 days was 65% (95% CI 58-71) overall: 72% (95% CI 58-81), 67% (95% CI 57-75) and 61% (95% CI 45-72) for non-VOC, B.1.1.7 and P.1, respectively. Conclusions: A single dose of mRNA vaccine reduced the risk of SARS-CoV-2 in adults ≥70-years-old by about two-thirds, with protection only minimally reduced against B.1.1.7 and P.1 variants. Substantial single-dose protection in older adults reinforces the option to defer the second dose when vaccine supply is scarce and broader first-dose coverage is needed.


2021 ◽  
Author(s):  
Mary Gaeddert ◽  
Philip Kitchen ◽  
Tobias Broger ◽  
Stefan Weber ◽  
Ralf Bartenschlager ◽  
...  

AbstractBackgroundAfter infection with severe acute respiratory syndrome coronavirus (SARS-CoV-2), Immunoglobulin G (IgG) antibodies and virus-specific neutralizing antibodies (nAbs) develop. This study describes antibody responses in a cohort of recovered COVID-19 patients to identify predictors.MethodsWe recruited patients with confirmed SARS-CoV-2 infection from Heidelberg, Germany. Blood samples were collected three weeks after COVID-19 symptoms ended. Participants with high antibody titers were invited for follow-up visits. IgG titers were measured by the Euroimmun Assay, and nAbs titers in a SARS-CoV-2 infection-based assay.Results281 participants were enrolled between April and August 2020 with IgG testing, 145 (51.6%) had nAbs, and 35 (12.5%) had follow-up. The median IgG optical density (OD) ratio was 3.1 (Interquartile range (IQR) 1.6-5.1), and 24.1% (35/145) had a nAb titer>1:80. Higher IgG titers were associated with increased age and more severe disease, and higher nAbs were associated with male gender and CT-value of 25-30 on RT-PCR at diagnosis. The median IgG OD ratio on follow-up was 3.7 (IQR 2.9-5.9), a median increase of 0.5 (IQR −0.3-1.7). Six participants with follow-up nAbs all had titers ≤ 1:80.ConclusionsWhile age and disease severity were correlated with IgG responses, predictive factors for nAbs in convalescent patients remain unclear.


2020 ◽  
Vol 9 (12) ◽  
pp. 3935
Author(s):  
Francesca Martini ◽  
Andrea D’Alessio ◽  
Federico Bracchi ◽  
Daniela Di Mauro ◽  
Anna Fargnoli ◽  
...  

Background The use of computed tomography (CT) for coronavirus disease 2019 (COVID-19) diagnosis in an area of northern Italy with a high incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may have identified more patients with this disease than RT-PCR in the very early onset of the COVID-19 pandemic. Methods We retrospectively reviewed 148 chest CT scans of oncological patients who were referred to the Radiological Unit of Policlinico S. Marco from 1 February 2020 to 30 April 2020, during the COVID-19 outbreak in Bergamo area. In parallel, we analyzed RT-PCR tests of these 148 patients. Results Among 32 patients with a diagnosis of COVID-19, 17 patients were asymptomatic or had mild symptoms (53.1%), while 15 developed severe disease (46.8%). The incidence of SARS-CoV-2 infection was 22.9%, the mortality rate was 18.8%. We did not find any correlation between disease severity and age, sex, smoking, or cardiovascular comorbidities. Remarkably, patients who were on treatment for cancer developed a milder disease than patients who were not on treatment. Conclusions The acceptance of CT-defined diagnoses in COVID-19 high-incidence areas like Bergamo region highlighted a larger oncological population affected by COVID-19 than RT-PCR, in particular, asymptomatic and mildly symptomatic patients, because only symptomatic patients underwent nasopharyngeal swabbing at the onset of the COVID-19 pandemic. We observed that patients actively treated for their cancer had a milder disease, in agreement with previous studies that suggested a protective role of immunosuppression. Admittedly, the sample of patients in our study was heterogeneous regarding the oncological disease, their prognosis, and the type of treatment; therefore, other studies are needed to confirm our data.


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