Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 248
Filter
Add filters

Document Type
Year range
1.
JAMA Netw Open ; 5(1): e2142210, 2022 01 04.
Article in English | MEDLINE | ID: covidwho-1611175

ABSTRACT

Importance: A surge of COVID-19 occurred from March to June 2021, in New Delhi, India, linked to the B.1.617.2 (Delta) variant of SARS-CoV-2. COVID-19 vaccines were rolled out for health care workers (HCWs) starting in January 2021. Objective: To assess the incidence density of reinfection among a cohort of HCWs and estimate the effectiveness of the inactivated whole virion vaccine BBV152 against reinfection. Design, Setting, and Participants: This was a retrospective cohort study among HCWs working at a tertiary care center in New Delhi, India. Exposures: Vaccination with 0, 1, or 2 doses of BBV152. Main Outcomes and Measures: The HCWs were categorized as fully vaccinated (with 2 doses and ≥15 days after the second dose), partially vaccinated (with 1 dose or 2 doses with <15 days after the second dose), or unvaccinated. The incidence density of COVID-19 reinfection per 100 person-years was computed, and events from March 3, 2020, to June 18, 2021, were included for analysis. Unadjusted and adjusted hazard ratios (HRs) were estimated using a Cox proportional hazards model. Estimated vaccine effectiveness (1 - adjusted HR) was reported. Results: Among 15 244 HCWs who participated in the study, 4978 (32.7%) were diagnosed with COVID-19. The mean (SD) age was 36.6 (10.3) years, and 55.0% were male. The reinfection incidence density was 7.26 (95% CI: 6.09-8.66) per 100 person-years (124 HCWs [2.5%], total person follow-up period of 1696 person-years as time at risk). Fully vaccinated HCWs had lower risk of reinfection (HR, 0.14 [95% CI, 0.08-0.23]), symptomatic reinfection (HR, 0.13 [95% CI, 0.07-0.24]), and asymptomatic reinfection (HR, 0.16 [95% CI, 0.05-0.53]) compared with unvaccinated HCWs. Accordingly, among the 3 vaccine categories, reinfection was observed in 60 of 472 (12.7%) of unvaccinated (incidence density, 18.05 per 100 person-years; 95% CI, 14.02-23.25), 39 of 356 (11.0%) of partially vaccinated (incidence density 15.62 per 100 person-years; 95% CI, 11.42-21.38), and 17 of 1089 (1.6%) fully vaccinated (incidence density 2.18 per 100 person-years; 95% CI, 1.35-3.51) HCWs. The estimated effectiveness of BBV152 against reinfection was 86% (95% CI, 77%-92%); symptomatic reinfection, 87% (95% CI, 76%-93%); and asymptomatic reinfection, 84% (95% CI, 47%-95%) among fully vaccinated HCWs. Partial vaccination was not associated with reduced risk of reinfection. Conclusions and Relevance: These findings suggest that BBV152 was associated with protection against both symptomatic and asymptomatic reinfection in HCWs after a complete vaccination schedule, when the predominant circulating variant was B.1.617.2.


Subject(s)
COVID-19/epidemiology , Health Personnel , Reinfection , SARS-CoV-2 , Adult , COVID-19/etiology , COVID-19/prevention & control , COVID-19 Vaccines/administration & dosage , Cohort Studies , Female , Humans , Immunogenicity, Vaccine , India/epidemiology , Male , Middle Aged , Surveys and Questionnaires , Tertiary Care Centers , Vaccines, Inactivated/administration & dosage , Virion/immunology , Young Adult
2.
PLoS One ; 17(1): e0262164, 2022.
Article in English | MEDLINE | ID: covidwho-1607493

ABSTRACT

Given the overwhelming worldwide rate of infection and the disappointing pace of vaccination, addressing reinfection is critical. Understanding reinfection, including longevity after natural infection, will allow us to better know the prospect of herd immunity, which hinges on the assumption that natural infection generates sufficient, protective immunity. The primary objective of this observational cohort study is to establish the incidence of reinfection of COVID-19 among healthcare employees who experienced a prior COVID-19 infection over a 10-month period. Of 2,625 participants who experienced at least one COVID-19 infection during the 10-month study period, 156 (5.94%) experienced reinfection and 540 (20.57%) experienced recurrence after prior infection. Median days were 126.50 (105.50-171.00) to reinfection and 31.50 (10.00-72.00) to recurrence. Incidence rate of COVID-19 reinfection was 0.35 cases per 1,000 person-days, with participants working in COVID-clinical and clinical units experiencing 3.77 and 3.57 times, respectively, greater risk of reinfection relative to those working in non-clinical units. Incidence rate of COVID-19 recurrence was 1.47 cases per 1,000 person-days. This study supports the consensus that COVID-19 reinfection, defined as subsequent infection ≥ 90 days after prior infection, is rare, even among a sample of healthcare workers with frequent exposure.


Subject(s)
COVID-19/pathology , Health Personnel , Reinfection/epidemiology , COVID-19/epidemiology , Cohort Studies , Humans , Illinois/epidemiology , Wisconsin/epidemiology
4.
Eur Rev Med Pharmacol Sci ; 25(24): 8019-8022, 2021 12.
Article in English | MEDLINE | ID: covidwho-1605687

ABSTRACT

Recently a new variant of SARS-CoV-2 was reported from South Africa. World Health Organization (WHO) named this mutant as a variant of concern - Omicron (B.1.1.529) on 26th November 2021. This variant exhibited more than thirty amino acid mutations in the spike protein. This mutation rate is exceeding the other variants by approximately 5-11 times in the receptor-binding motif of the spike protein. Omicron (B.1.1.529) variant might have enhanced transmissibility and immune evasion. This new variant can reinfect individuals previously infected with other SARS-CoV-2 variants. Scientists expressed their concern about the efficacy of already existing COVID-19 vaccines against Omicron (B.1.1.529) infections. Some of the crucial mutations that are detected in the receptor-binding domain of the Omicron variant have been shared by previously evolved SARS-CoV-2 variants. Based on the Omicron mutation profile in the receptor-binding domain and motif, it might have collectively enhanced or intermediary infectivity relative to its previous variants. Due to extensive mutations in the spike protein, the Omicron variant might evade the immunity in the vaccinated individuals.


Subject(s)
COVID-19/epidemiology , Reinfection/epidemiology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , COVID-19/immunology , COVID-19/transmission , COVID-19/virology , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , COVID-19 Vaccines/therapeutic use , Humans , Immune Evasion/genetics , Immunogenicity, Vaccine , Mutation , Reinfection/immunology , Reinfection/transmission , Reinfection/virology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Vaccine Potency
5.
AIDS Rev ; 23(3): 153-163, 2021 06 03.
Article in English | MEDLINE | ID: covidwho-1579385

ABSTRACT

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly infectious RNA coronavirus responsible for the pandemic of the coronavirus disease 2019 (COVID-19). Recent advances in virology, epidemiology, diagnosis, and clinical management of COVID-19 have contributed to the control and prevention of this disease, but re-positivity of SARS-CoV-2 in recovered COVID-19 patients has brought a new challenge for this worldwide anti-viral battle. Reverse transcription polymerase chain reaction (RT-PCR) tests of the SARS-CoV-2 pathogen is widely used in clinical diagnosis, but a positive RT-PCR result may be multifactorial, including false positive, SARS-CoV-2 RNA fragment shedding, reinfection of SARS-CoV-2, or re-activation of COVID-19. Re-infection of SARS-CoV-2 or re-activation of COVID-19 is an indicator of live viral carriers and isolation/treatment is needed, but SARS-CoV-2 RNA fragment shedding is not. SARS-CoV-2 RNA is recently reported to integrate into the host genome, but the far-reaching outcome is currently unclear. Therefore, it is critical for appropriate manipulation and prevention of COVID-19 to distinguish these causal factors of SARS-CoV-2 re-positivity. In this review article, we updated the current knowledge of SARS-CoV-2 re-positivity in discharged COVID-19 patients with a focus on re-infection and re-activation. We proposed a hypothetical flowchart for handling of the SARS-CoV-2 re-positive cases.


Subject(s)
COVID-19/pathology , RNA, Viral/analysis , Reinfection/virology , SARS-CoV-2/genetics , Virus Activation/genetics , Adaptive Immunity/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Viral/blood , COVID-19/diagnosis , Child , Child, Preschool , False Positive Reactions , Female , Humans , Infant , Male , Middle Aged , Reverse Transcriptase Polymerase Chain Reaction , Young Adult
6.
Rev Med Virol ; 31(5): 1-12, 2021 09.
Article in English | MEDLINE | ID: covidwho-1574832

ABSTRACT

With a large number of coronavirus disease 2019 (Covid-19) patients being discharged from hospital with negative test results for SARS-CoV-2, it has been reported that several recovered cases tested positive after discharge (re-positive, RP). This finding has raised several important questions for this novel coronavirus and Covid-19 disease. In this review, we have discussed several important questions, including: (1) Can the virus re-infect recovered individuals? (2) What are the possible causes of the re-positive reverse transcriptase-polymerase chain reaction (RT-PCR) test in recovered patients? (3) What are the implications of these re-positive cases concerning the spread of the virus? Understanding how recovery from Covid-19 confers immunity to decrease the risk of re-infection is needed to inform current efforts to safely scale back population-based interventions, such as physical distancing. We have also described what is currently known about the immune response to Covid-19, highlighted key gaps in knowledge, and identified opportunities for future research. Overall, the quality of the evidence is poor and we describe the features that should be described for future cases.


Subject(s)
COVID-19/virology , Reinfection/virology , SARS-CoV-2/physiology , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , SARS-CoV-2/genetics , Young Adult
9.
PLoS Med ; 18(12): e1003879, 2021 12.
Article in English | MEDLINE | ID: covidwho-1573611

ABSTRACT

BACKGROUND: The epidemiology of the SARS-CoV-2 B.1.1.7 (or Alpha) variant is insufficiently understood. This study's objective was to describe the introduction and expansion of this variant in Qatar and to estimate the efficacy of natural infection against reinfection with this variant. METHODS AND FINDINGS: Reinfections with the B.1.1.7 variant and variants of unknown status were investigated in a national cohort of 158,608 individuals with prior PCR-confirmed infections and a national cohort of 42,848 antibody-positive individuals. Infections with B.1.1.7 and variants of unknown status were also investigated in a national comparator cohort of 132,701 antibody-negative individuals. B.1.1.7 was first identified in Qatar on 25 December 2020. Sudden, large B.1.1.7 epidemic expansion was observed starting on 18 January 2021, triggering the onset of epidemic's second wave, 7 months after the first wave. B.1.1.7 was about 60% more infectious than the original (wild-type) circulating variants. Among persons with a prior PCR-confirmed infection, the efficacy of natural infection against reinfection was estimated to be 97.5% (95% CI: 95.7% to 98.6%) for B.1.1.7 and 92.2% (95% CI: 90.6% to 93.5%) for variants of unknown status. Among antibody-positive persons, the efficacy of natural infection against reinfection was estimated to be 97.0% (95% CI: 92.5% to 98.7%) for B.1.1.7 and 94.2% (95% CI: 91.8% to 96.0%) for variants of unknown status. A main limitation of this study is assessment of reinfections based on documented PCR-confirmed reinfections, but other reinfections could have occurred and gone undocumented. CONCLUSIONS: In this study, we observed that introduction of B.1.1.7 into a naïve population can create a major epidemic wave, but natural immunity in those previously infected was strongly associated with limited incidence of reinfection by B.1.1.7 or other variants.


Subject(s)
COVID-19/epidemiology , COVID-19/virology , Reinfection/epidemiology , Reinfection/virology , SARS-CoV-2 , Adolescent , Adult , Aged , Aged, 80 and over , Basic Reproduction Number , Child , Female , Humans , Immunity, Innate , Male , Middle Aged , Models, Theoretical , Polymerase Chain Reaction , Qatar/epidemiology , Retrospective Studies , Time Factors , Young Adult
11.
J Med Virol ; 94(1): 44-53, 2022 01.
Article in English | MEDLINE | ID: covidwho-1544334

ABSTRACT

Recent studies reported that some recovered COVID-19 patients have tested positive for virus nucleic acid again. A systematic search was performed in Web of Science, PubMed, Scopus, and Google Scholar up to March 6, 2021. The pooled estimation of reinfection, recurrence, and hospital readmission among recovered COVID-19 patients was 3, 133, and 75 per 1000 patients, respectively. The overall estimation of reinfection among males compared to females was greater. The prevalence of recurrence in females compared to males was more common. Also, hospital readmission between sex groups was the same. There is uncertainty about long-term immunity after SARS-Cov-2 infection. Thus, the possibility of reinfection and recurrence after recovery is not unexpected. In addition, there is a probability of hospital readmission due to adverse events of COVID-19 after discharge. However, with mass vaccination of people and using the principles of prevention and appropriate management of the disease, frequent occurrence of the disease can be controlled.


Subject(s)
COVID-19/epidemiology , Patient Readmission/statistics & numerical data , Reinfection/epidemiology , SARS-CoV-2/isolation & purification , COVID-19 Vaccines/immunology , Female , Humans , Male , Recurrence , SARS-CoV-2/immunology , Sex Factors , Sex Ratio , Vaccination
13.
J Med Case Rep ; 15(1): 572, 2021 Nov 26.
Article in English | MEDLINE | ID: covidwho-1538088

ABSTRACT

BACKGROUND: Hydroxychloroquine and chloroquine have been used for hospitalized coronavirus disease 2019 patients because of their antiviral and anti-inflammatory function. However, little research has been published on the impact of the immunomodulatory effect of (hydroxy)chloroquine on humoral immunity. CASE PRESENTATION: We report a case of symptomatic severe acute respiratory syndrome coronavirus 2 reinfection, diagnosed 141 days after the first episode, in a 56-year-old man of Black African origin treated with hydroxychloroquine for lupus erythematosus. No anti-severe acute respiratory syndrome coronavirus 2 IgG antibodies could be detected 127 days after the initial episode of coronavirus disease 2019. CONCLUSIONS: The treatment with hydroxychloroquine probably explains the decreased immune response with negative serology and subsequent reinfection in our patient. As humoral immunity is crucial to fight a severe acute respiratory syndrome coronavirus 2 infection, the use of (hydroxy)chloroquine is likely to have a detrimental effect on the spread of the virus. This case emphasizes that more needs to be learned about the role of antibodies in protecting against severe acute respiratory syndrome coronavirus 2 (re)infection and the role of (hydroxy)chloroquine on humoral immunity.


Subject(s)
COVID-19 , Hydroxychloroquine , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Humans , Hydroxychloroquine/therapeutic use , Middle Aged , Reinfection , SARS-CoV-2
15.
Clin Infect Dis ; 73(10): 1882-1886, 2021 11 16.
Article in English | MEDLINE | ID: covidwho-1522147

ABSTRACT

BACKGROUND: Protection afforded from prior disease among patients with coronavirus disease 2019 (COVID-19) infection is unknown. If infection provides substantial long-lasting immunity, it may be appropriate to reconsider vaccination distribution. METHODS: This retrospective cohort study of 1 health system included 150 325 patients tested for COVID-19 infection via polymerase chain reaction from 12 March 2020 to 30 August 2020. Testing performed up to 24 February 2021 in these patients was included. The main outcome was reinfection, defined as infection ≥90 days after initial testing. Secondary outcomes were symptomatic infection and protection of prior infection against reinfection. RESULTS: Of 150 325 patients, 8845 (5.9%) tested positive and 141 480 (94.1%) tested negative before 30 August. A total of 1278 (14.4%) positive patients were retested after 90 days, and 62 had possible reinfection. Of those, 31 (50%) were symptomatic. Of those with initial negative testing, 5449 (3.9%) were subsequently positive and 3191 of those (58.5%) were symptomatic. Protection offered from prior infection was 81.8% (95% confidence interval [CI], 76.6-85.8) and against symptomatic infection was 84.5% (95% CI, 77.9-89.1). This protection increased over time. CONCLUSIONS: Prior infection in patients with COVID-19 was highly protective against reinfection and symptomatic disease. This protection increased over time, suggesting that viral shedding or ongoing immune response may persist beyond 90 days and may not represent true reinfection. As vaccine supply is limited, patients with known history of COVID-19 could delay early vaccination to allow for the most vulnerable to access the vaccine and slow transmission.


Subject(s)
COVID-19 , Humans , Longitudinal Studies , Reinfection , Retrospective Studies , SARS-CoV-2
18.
Cell ; 184(26): 6229-6242.e18, 2021 12 22.
Article in English | MEDLINE | ID: covidwho-1520753

ABSTRACT

SARS-CoV-2 variants of concern exhibit varying degrees of transmissibility and, in some cases, escape from acquired immunity. Much effort has been devoted to measuring these phenotypes, but understanding their impact on the course of the pandemic-especially that of immune escape-has remained a challenge. Here, we use a mathematical model to simulate the dynamics of wild-type and variant strains of SARS-CoV-2 in the context of vaccine rollout and nonpharmaceutical interventions. We show that variants with enhanced transmissibility frequently increase epidemic severity, whereas those with partial immune escape either fail to spread widely or primarily cause reinfections and breakthrough infections. However, when these phenotypes are combined, a variant can continue spreading even as immunity builds up in the population, limiting the impact of vaccination and exacerbating the epidemic. These findings help explain the trajectories of past and present SARS-CoV-2 variants and may inform variant assessment and response in the future.


Subject(s)
COVID-19/immunology , COVID-19/transmission , Immune Evasion , SARS-CoV-2/immunology , COVID-19/epidemiology , COVID-19/virology , Computer Simulation , Humans , Immunity , Models, Biological , Reinfection , Vaccination
20.
J Med Case Rep ; 15(1): 557, 2021 Nov 11.
Article in English | MEDLINE | ID: covidwho-1511757

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 reinfection prevalence is unknown. It is essential to understand reinfection symptoms and, importantly, the lived experience. CASE PRESENTATION: Case study design is the best method for understanding this contemporary pandemic and rare occurrence of reinfections. A 19-year-old White Non-Hispanic woman presented with presumed severe acute respiratory syndrome coronavirus 2 reinfection 6 weeks after initially mild symptomatic infection and consistent repeat negative results. Real-time reverse-transcription polymerase chain reaction from saliva was used for detection. Twice-weekly saliva samples were collected (a) before initial infection, (b) resumed on day 10 after initial infection until reinfection was detected, and (c) resumed on day 10 post-reinfection. A 1.5-hour virtual interview was conducted, transcribed, and independently analyzed by two researchers. Four themes emerged: (1) perceived invincibility or inevitability and subsequent immunity increases risk of transmission via inconsistent preventive behaviors; (2) normalcy desires, trusted others, and implicit social pressures to not wear masks and distance increase one's coronavirus disease 2019 risk; (3) physical symptoms are more severe with reinfection compared with first infection; and (4) mental health sequelae (trauma and stigma) are more severe and enduring than physical health outcomes. CONCLUSIONS: Unmasked social interactions contradicting public health recommendations were rationalized by social circle members with heavy reliance on feeling asymptomatic, lacking a positive test (testing negative or not testing), or attributing symptoms to allergies. Stigma of testing positive and consequences of not conforming to social group behaviors is overwhelming and creates pressure to take risks. This case study provides insights and lessons learned relevant for public health messaging and continued preventive behaviors.


Subject(s)
COVID-19 , Adult , Female , Humans , Pandemics , Public Health , Reinfection , SARS-CoV-2 , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL
...