Transmissibility of SARS-CoV-2 among fully vaccinated individuals.
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ABSTRACT:
SUBMITTER: Ko HHT
PROVIDER: S-EPMC8694704 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundThe first case of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in Rio Grande do Norte, northeastern Brazil, was diagnosed on March 12, 2020; thereafter, multiple surges of infection occurred, similar to what was seen elsewhere. These surges were mostly due to SARS-CoV-2 mutations leading to emergence of variants of concern (VoC). The introduction of new VoCs in a population previously exposed to SARS-CoV-2 or after vaccination has been a challenge to understanding the kinetics of the protective immune response against this virus. The aim of this study was to investigate the outbreak of SARS-CoV-2 reinfections observed in mid-January 2022 in Rio Grande do Norte state, Brazil. It describes the clinical and genomic characteristics of nine cases of reinfection that occurred coincident with the introduction of the omicron variant.Methodology/principal findingsOf a total of 172,965 individuals with upper respiratory symptoms tested for SARS-CoV-2, between March 2020 through mid-February 2022, 58,097 tested positive. Of those, 444 had documented a second SARS-CoV-2 infection and nine reinfection cases were selected for sequencing. Genomic analysis revealed that virus lineages diverged between primary infections and the reinfections, with the latter caused by the Omicron (BA.1) variant among individuals fully vaccinated against SARS-CoV-2.Conclusions/significanceOur findings suggest that the Omicron variant is able to evade both natural and vaccine-induced immunity, since all nine cases had prior natural infection and, in addition, were fully vaccinated, emphasizing the need to develop effective blocking vaccines.
| S-EPMC9560550 | biostudies-literature
Project description:BackgroundCOVID-19 messenger RNA (mRNA) vaccines have demonstrated efficacy and effectiveness in preventing symptomatic COVID-19, while being relatively safe in trial studies. However, vaccine breakthrough infections have been reported.ObjectiveThis study aims to identify risk factors associated with COVID-19 breakthrough infections among fully mRNA-vaccinated individuals.MethodsWe conducted a series of observational retrospective analyses using the electronic health records (EHRs) of the Columbia University Irving Medical Center/New York Presbyterian (CUIMC/NYP) up to September 21, 2021. New York City (NYC) adult residences with at least 1 polymerase chain reaction (PCR) record were included in this analysis. Poisson regression was performed to assess the association between the breakthrough infection rate in vaccinated individuals and multiple risk factors-including vaccine brand, demographics, and underlying conditions-while adjusting for calendar month, prior number of visits, and observational days in the EHR.ResultsThe overall estimated breakthrough infection rate was 0.16 (95% CI 0.14-0.18). Individuals who were vaccinated with Pfizer/BNT162b2 (incidence rate ratio [IRR] against Moderna/mRNA-1273=1.66, 95% CI 1.17-2.35) were male (IRR against female=1.47, 95% CI 1.11-1.94) and had compromised immune systems (IRR=1.48, 95% CI 1.09-2.00) were at the highest risk for breakthrough infections. Among all underlying conditions, those with primary immunodeficiency, a history of organ transplant, an active tumor, use of immunosuppressant medications, or Alzheimer disease were at the highest risk.ConclusionsAlthough we found both mRNA vaccines were effective, Moderna/mRNA-1273 had a lower incidence rate of breakthrough infections. Immunocompromised and male individuals were among the highest risk groups experiencing breakthrough infections. Given the rapidly changing nature of the SARS-CoV-2 pandemic, continued monitoring and a generalizable analysis pipeline are warranted to inform quick updates on vaccine effectiveness in real time.
| S-EPMC9132195 | biostudies-literature
Project description:The emergence of the SARS-CoV-2 B.1.617.2 lineage (Delta variant) in 2021 was associated with increased case numbers and test positivity rates, including a large number of infections in fully vaccinated individuals. Here, we describe the findings of an investigation conducted in Tompkins County, New York, to evaluate factors underlying a significant uptick in the number of coronavirus disease 2019 (COVID-19) cases observed in the months of July and August 2021. We performed genomic surveillance and genotyping as well as virological assessments to determine infectivity of the virus in a select number of clinical diagnostic samples. Genomic sequence analyses revealed complete replacement of the B.1.1.7 lineage (Alpha variant) with the B.1.617.2 lineage (Delta variant) between July 1 and August 4 2021. We observed a strong association between viral RNA loads detected by real-time reverse transcriptase PCR and infectious virus detected in respiratory secretions by virus titration. A marked increase in positive cases among fully vaccinated individuals was observed. The sequence divergence between two index Delta variant cases in April and May, and the cases after July 1st, revealed independent Delta variant introductions in Tompkins County. Contact tracing information enabled the detection of clusters of connected cases within closely related phylogenetic clusters. We also found evidence of transmission between vaccinated individuals and between vaccinated and unvaccinated individuals. This was confirmed by detection and isolation of infectious virus from a group of individuals within epidemiologically connected transmission clusters, confirming shedding of high viral loads and transmission of the virus by fully vaccinated individuals. IMPORTANCE The SARS-CoV-2 lineage B.1.617.2 (Delta variant) emerged in Asia and rapidly spread to other countries, becoming the dominant circulating lineage. Worldwide infections with B.1.617.2 peaked at a time in which vaccination rates were increasing. In this study, we present data characterizing the emergence of SARS-CoV-2 lineage B.1.617.2 (Delta variant) in Tompkins County, New York, which has one of the highest vaccination rates in the state. We present evidence demonstrating infection, replication, and transmission of SARS-CoV-2 lineage B.1.617.2 (Delta variant) between fully vaccinated individuals. Importantly, infectious virus loads were determined in a subset of samples and demonstrated shedding of high viral titers in respiratory secretions of vaccinated individuals.
| S-EPMC9602338 | biostudies-literature
Project description:Prophylactic vaccination against SARS-CoV-2 is one of the most important measures to contain the COVID-19 pandemic. Recently, break-through infections following vaccination against this virus have been reported. Here, we describe the humoral immune response of break-through infections in fully vaccinated individuals of old age from an outbreak in a nursing home. In cooperation with the local health authority, blood samples from fully vaccinated and infected as well as fully vaccinated and uninfected residents of the nursing home were collected 4 weeks after the onset of the outbreak. The humoral immune response was determined in a neutralisation assay with replication-competent virus isolates and by a quantitative ELISA. In this outbreak a total of 23 residents and four health care workers were tested positive for SARS-CoV-2. Four residents were unvaccinated, including one with a severe course of disease who later severe disease course who later succumbed to infection. Despite their old age, all vaccinated residents showed no or only mild disease. Comparison of the humoral immune response revealed significantly higher antibody levels in fully vaccinated infected individuals compared to fully vaccinated uninfected individuals (p < 0.001). Notably, although only a minority of the vaccinated uninfected group showed neutralisation capacity against SARS-CoV-2, all vaccinated and infected individuals showed high-titre neutralisation of SARS-CoV-2 including the alpha and beta variant. Large SARS-CoV-2 outbreaks can occur in fully vaccinated populations, but seem to associate with mild disease. SARS-CoV-2 infection in fully vaccinated individuals is a strong booster of the humoral immune response providing enhanced neutralisation capacity against immune evasion variants.
| S-EPMC8544807 | biostudies-literature
Project description:ObjectiveTo evaluate the effectiveness of the Pfizer BNT162b2 vaccine against the SARS-Cov-2 Beta variant.Study design and settingIsrael's mass vaccination program, using two doses of the Pfizer BNT162b2 vaccine, successfully curtailed the Alpha variant outbreak during winter 2020-2021, However, the virus may mutate and partially evade the immune system. To monitor this, sequencing of selected positive swab samples of interest was initiated. Comparing vaccinated with unvaccinated PCR positive persons, we estimated the odds ratio for a vaccinated case to have the Beta vs. the Alpha variant, using logistic regression, controlling for important confounders.ResultsThere were 19 cases of Beta variant (3.2%) among those vaccinated more than 14 days before the positive sample and 79 (3.4%) among the unvaccinated. The estimated odds ratio was 1.26 (95% CI: 0.65-2.46). Assuming the effectiveness against the Alpha variant to be 95%, the estimated effectiveness against the Beta variant was 94% (95% CI: 88%-98%).ConclusionDespite concerns over the Beta variant, the BNT162b2 vaccine seemed to provide substantial immunity against both the Beta and the Alpha variants. From 14 days following the second vaccine dose, the effectiveness of BNT162b2 vaccine was at most marginally affected by the Beta variant.
| S-EPMC8553421 | biostudies-literature
Project description:ObjectiveWe aimed to identify risk factors for hospital admission and severe disease among fully vaccinated (FV) individuals with COVID-19. Further, we investigated if risk factors for hospitalization and severe disease are similar between unvaccinated (UV) and vaccinated individuals.MethodsThis was a multicenter, observational cohort analysis from a large regional healthcare system in metro Detroit using electronic health record data to evaluate risk factors for hospitalization and severe COVID-19 disease. Vaccination data were retrieved using electronic medical records linked to our statewide immunization database. Consecutive adult FV and UV patients with a primary admission diagnosis of COVID-19 were included in the comparative analysis. Partially vaccinated patients and patients who had received a booster dose were excluded. The primary outcome of this study was hospital admission and severe disease inclusive of intensive care unit (ICU) admission, mechanical ventilation, or death.ResultsBetween December 15, 2020 and December 19, 2021, 20,584 emergency department visits met our inclusion criteria. Among these, 2005 (9.7%) visits consisted of FV individuals, 18,579 (90.3%) were UV, and 40.3% of UV and 52.7% of FV required hospitalization with similar (12.7% and 12.6%, respectively) rates of severe disease. Hospitalized UV patients with severe disease were younger than their FV counterparts (49.5% <65 years vs. 13.5% p < 0.001). Risk factors for severe disease on UV and FV included age ≥65 years (UV: adjusted odds ratio [aOR] 1.49, 95% confidence interval [CI] 1.28-1.73, p < 0.001 and FV: aOR 2.50, 95% CI 1.44-4.36 p = 0.001) and weighted Elixhauser score >10 (UV: aOR 9.11, 95% CI 6.92-12.00, p < 0.001 and FV: aOR 6.04, 95% CI 2.68-13.26, p < 0.001). However, only on UV status, body mass index (BMI) ≥30 kg/m2 was associated with increased odds of severe disease (aOR 2.59, 95% CI 2.09-3.22, p < 0.001).ConclusionsFV patients with breakthrough SARS-CoV-2 infection who require hospitalization and have severe disease are older and have more medical comorbidities compared to UV patients. When comparing risk factors for severe disease between UV and FV individuals, FV status is particularly associated with reduced risk among patients with a BMI ≥30 kg/m2 and a moderate number of medical comorbidities, regardless of age, highlighting the importance of vaccination in these particularly vulnerable groups.
| S-EPMC9337843 | biostudies-literature
Project description:Omicron has become the globally dominant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, creating additional challenges due to its ability to evade neutralization. Here, we report that neutralizing antibodies against Omicron variants are undetected following COVID-19 infection with ancestral or past SARS-CoV-2 variant viruses or after two-dose mRNA vaccination. Compared with two-dose vaccination, a three-dose vaccination course induces broad neutralizing antibody responses with improved durability against different SARS-CoV-2 variants, although neutralizing antibody titers against Omicron remain low. Intriguingly, among individuals with three-dose vaccination, Omicron breakthrough infection substantially augments serum neutralizing activity against a broad spectrum of SARS-CoV-2 variants, including Omicron variants BA.1, BA.2, and BA.5. Additionally, after Omicron breakthrough infection, memory T cells respond to the spike proteins of both ancestral and Omicron SARS-CoV-2 by producing cytokines with polyfunctionality. These results suggest that Omicron breakthrough infection following three-dose mRNA vaccination induces pan-SARS-CoV-2 immunity that may protect against emerging SARS-CoV-2 variants of concern.
| S-EPMC9482837 | biostudies-literature
Project description:Breakthrough infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have been reported frequently in vaccinated individuals with waning immunity. In particular, a cluster of over 1000 infections with the SARS-CoV-2 delta variant was identified in a predominantly fully vaccinated population in Provincetown, Massachusetts in July 2021. In this study, vaccinated individuals who tested positive for SARS-CoV-2 (n = 16) demonstrated substantially higher serum antibody responses than vaccinated individuals who tested negative for SARS-CoV-2 (n = 23), including 32-fold higher binding antibody titers and 31-fold higher neutralizing antibody titers against the SARS-CoV-2 delta variant. Vaccinated individuals who tested positive also showed higher mucosal antibody responses in nasal secretions and higher spike protein-specific CD8+ T cell responses in peripheral blood than did vaccinated individuals who tested negative. These data demonstrate that fully vaccinated individuals developed robust anamnestic antibody and T cell responses after infection with the SARS-CoV-2 delta variant. Moreover, these findings suggest that population immunity will likely increase over time by a combination of widespread vaccination and breakthrough infections.
| S-EPMC8995036 | biostudies-literature
Project description: Not available
| S-EPMC8669415 | biostudies-literature
Project description:BackgroundThe SARS-CoV-2 Delta variant was first identified in the U.S. in March 2021 and has rapidly become the predominant lineage across the U.S. due to increased transmissibility, immune evasion and vaccine breakthrough. The aim of this study was to better understand the genetic diversity and the potential impact of mutations observed in SARS-CoV-2 viruses circulating in the U.S. in vaccinated individuals.ResultsWhole genome sequencing was performed on thirty-four SARS-CoV-2 positive samples using the Oxford Nanopore MinION. Evolutionary genomic analysis revealed two novel mutations, ORF1b:V2354F and a premature stop codon, ORF7a:Q94*, identified in a cluster of SARS-CoV-2 Delta isolates collected from vaccinated individuals in Colorado. The ORF1b:V2354F mutation, corresponding to NSP15:V303F, may induce a conformational change and result in a disruption to a flanking beta-sheet structure. The premature stop codon, ORF7a:Q94*, truncates the transmembrane protein and cytosolic tail used to mediate protein transport. This may affect protein localization to the ER-Golgi. In addition to these novel mutations, the cluster of vaccinated isolates contain an additional mutation in the spike protein, at position 112, compared to the Delta variant defining mutations. This mutation, S112L, exists in isolates previously obtained in the U.S. The S112L mutation substitutes a bulky hydrophobic side chain for a polar side chain, which results in a non-conservative substitution within the protein that may affect antibody-binding affinity. Additionally, the vaccinated cluster of isolates contains non-synonymous mutations within ORF8 and NSPs which further distinguish this cluster from the respective ancestral Delta variant.ConclusionsThese results show there is an emerging sub-lineage of the ancestral Delta variant circulating in the U.S. As mutations emerge in constellations, those with a potentially beneficial advantage to the virus may continue to circulate while others will cease.
| S-EPMC9166184 | biostudies-literature