Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 8 de 8
Filter
1.
Cochrane Database Syst Rev ; 11: CD013652, 2022 11 17.
Article in English | MEDLINE | ID: covidwho-2119253

ABSTRACT

BACKGROUND: The diagnostic challenges associated with the COVID-19 pandemic resulted in rapid development of diagnostic test methods for detecting SARS-CoV-2 infection. Serology tests to detect the presence of antibodies to SARS-CoV-2 enable detection of past infection and may detect cases of SARS-CoV-2 infection that were missed by earlier diagnostic tests. Understanding the diagnostic accuracy of serology tests for SARS-CoV-2 infection may enable development of effective diagnostic and management pathways, inform public health management decisions and understanding of SARS-CoV-2 epidemiology. OBJECTIVES: To assess the accuracy of antibody tests, firstly, to determine if a person presenting in the community, or in primary or secondary care has current SARS-CoV-2 infection according to time after onset of infection and, secondly, to determine if a person has previously been infected with SARS-CoV-2. Sources of heterogeneity investigated included: timing of test, test method, SARS-CoV-2 antigen used, test brand, and reference standard for non-SARS-CoV-2 cases. SEARCH METHODS: The COVID-19 Open Access Project living evidence database from the University of Bern (which includes daily updates from PubMed and Embase and preprints from medRxiv and bioRxiv) was searched on 30 September 2020. We included additional publications from the Evidence for Policy and Practice Information and Co-ordinating Centre (EPPI-Centre) 'COVID-19: Living map of the evidence' and the Norwegian Institute of Public Health 'NIPH systematic and living map on COVID-19 evidence'. We did not apply language restrictions. SELECTION CRITERIA: We included test accuracy studies of any design that evaluated commercially produced serology tests, targeting IgG, IgM, IgA alone, or in combination. Studies must have provided data for sensitivity, that could be allocated to a predefined time period after onset of symptoms, or after a positive RT-PCR test. Small studies with fewer than 25 SARS-CoV-2 infection cases were excluded. We included any reference standard to define the presence or absence of SARS-CoV-2 (including reverse transcription polymerase chain reaction tests (RT-PCR), clinical diagnostic criteria, and pre-pandemic samples). DATA COLLECTION AND ANALYSIS: We use standard screening procedures with three reviewers. Quality assessment (using the QUADAS-2 tool) and numeric study results were extracted independently by two people. Other study characteristics were extracted by one reviewer and checked by a second. We present sensitivity and specificity with 95% confidence intervals (CIs) for each test and, for meta-analysis, we fitted univariate random-effects logistic regression models for sensitivity by eligible time period and for specificity by reference standard group. Heterogeneity was investigated by including indicator variables in the random-effects logistic regression models. We tabulated results by test manufacturer and summarised results for tests that were evaluated in 200 or more samples and that met a modification of UK Medicines and Healthcare products Regulatory Agency (MHRA) target performance criteria. MAIN RESULTS: We included 178 separate studies (described in 177 study reports, with 45 as pre-prints) providing 527 test evaluations. The studies included 64,688 samples including 25,724 from people with confirmed SARS-CoV-2; most compared the accuracy of two or more assays (102/178, 57%). Participants with confirmed SARS-CoV-2 infection were most commonly hospital inpatients (78/178, 44%), and pre-pandemic samples were used by 45% (81/178) to estimate specificity. Over two-thirds of studies recruited participants based on known SARS-CoV-2 infection status (123/178, 69%). All studies were conducted prior to the introduction of SARS-CoV-2 vaccines and present data for naturally acquired antibody responses. Seventy-nine percent (141/178) of studies reported sensitivity by week after symptom onset and 66% (117/178) for convalescent phase infection. Studies evaluated enzyme-linked immunosorbent assays (ELISA) (165/527; 31%), chemiluminescent assays (CLIA) (167/527; 32%) or lateral flow assays (LFA) (188/527; 36%). Risk of bias was high because of participant selection (172, 97%); application and interpretation of the index test (35, 20%); weaknesses in the reference standard (38, 21%); and issues related to participant flow and timing (148, 82%). We judged that there were high concerns about the applicability of the evidence related to participants in 170 (96%) studies, and about the applicability of the reference standard in 162 (91%) studies. Average sensitivities for current SARS-CoV-2 infection increased by week after onset for all target antibodies. Average sensitivity for the combination of either IgG or IgM was 41.1% in week one (95% CI 38.1 to 44.2; 103 evaluations; 3881 samples, 1593 cases), 74.9% in week two (95% CI 72.4 to 77.3; 96 evaluations, 3948 samples, 2904 cases) and 88.0% by week three after onset of symptoms (95% CI 86.3 to 89.5; 103 evaluations, 2929 samples, 2571 cases). Average sensitivity during the convalescent phase of infection (up to a maximum of 100 days since onset of symptoms, where reported) was 89.8% for IgG (95% CI 88.5 to 90.9; 253 evaluations, 16,846 samples, 14,183 cases), 92.9% for IgG or IgM combined (95% CI 91.0 to 94.4; 108 evaluations, 3571 samples, 3206 cases) and 94.3% for total antibodies (95% CI 92.8 to 95.5; 58 evaluations, 7063 samples, 6652 cases). Average sensitivities for IgM alone followed a similar pattern but were of a lower test accuracy in every time slot. Average specificities were consistently high and precise, particularly for pre-pandemic samples which provide the least biased estimates of specificity (ranging from 98.6% for IgM to 99.8% for total antibodies). Subgroup analyses suggested small differences in sensitivity and specificity by test technology however heterogeneity in study results, timing of sample collection, and smaller sample numbers in some groups made comparisons difficult. For IgG, CLIAs were the most sensitive (convalescent-phase infection) and specific (pre-pandemic samples) compared to both ELISAs and LFAs (P < 0.001 for differences across test methods). The antigen(s) used (whether from the Spike-protein or nucleocapsid) appeared to have some effect on average sensitivity in the first weeks after onset but there was no clear evidence of an effect during convalescent-phase infection. Investigations of test performance by brand showed considerable variation in sensitivity between tests, and in results between studies evaluating the same test. For tests that were evaluated in 200 or more samples, the lower bound of the 95% CI for sensitivity was 90% or more for only a small number of tests (IgG, n = 5; IgG or IgM, n = 1; total antibodies, n = 4). More test brands met the MHRA minimum criteria for specificity of 98% or above (IgG, n = 16; IgG or IgM, n = 5; total antibodies, n = 7). Seven assays met the specified criteria for both sensitivity and specificity. In a low-prevalence (2%) setting, where antibody testing is used to diagnose COVID-19 in people with symptoms but who have had a negative PCR test, we would anticipate that 1 (1 to 2) case would be missed and 8 (5 to 15) would be falsely positive in 1000 people undergoing IgG or IgM testing in week three after onset of SARS-CoV-2 infection. In a seroprevalence survey, where prevalence of prior infection is 50%, we would anticipate that 51 (46 to 58) cases would be missed and 6 (5 to 7) would be falsely positive in 1000 people having IgG tests during the convalescent phase (21 to 100 days post-symptom onset or post-positive PCR) of SARS-CoV-2 infection. AUTHORS' CONCLUSIONS: Some antibody tests could be a useful diagnostic tool for those in whom molecular- or antigen-based tests have failed to detect the SARS-CoV-2 virus, including in those with ongoing symptoms of acute infection (from week three onwards) or those presenting with post-acute sequelae of COVID-19. However, antibody tests have an increasing likelihood of detecting an immune response to infection as time since onset of infection progresses and have demonstrated adequate performance for detection of prior infection for sero-epidemiological purposes. The applicability of results for detection of vaccination-induced antibodies is uncertain.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , COVID-19/diagnosis , COVID-19/epidemiology , Antibodies, Viral , Immunoglobulin G , COVID-19 Vaccines , Pandemics , Seroepidemiologic Studies , Immunoglobulin M
3.
Am J Epidemiol ; 191(6): 987-998, 2022 05 20.
Article in English | MEDLINE | ID: covidwho-1684510

ABSTRACT

Identifying persons who are least willing to receive a coronavirus disease 2019 (COVID-19) vaccine is critical for increasing uptake via targeted outreach. We conducted a survey of 23,819 Canadian Longitudinal Study on Aging participants from September 29 to December 29, 2020, to assess factors associated with COVID-19 vaccination willingness and reasons for willingness or lack thereof. Among adults aged 50-96 years, 84.1% (95% confidence interval (CI): 83.7, 84.6) were very or somewhat willing to receive a COVID-19 vaccine; 15.9% (95% CI: 15.4, 16.3) were uncertain or very or somewhat unwilling. Based on logistic regression, those who were younger, female, had lower education and income, were non-White, and lived in a rural area were less willing to receive a COVID-19 vaccine. After controlling for these factors, recent receipt of influenza vaccine (adjusted odds ratio = 14.3, 95% CI: 12.5, 16.2) or planning to receive influenza vaccine (adjusted odds ratio = 10.5, 95% CI: 9.5, 11.6), as compared with no receipt or planning, was most strongly associated with COVID-19 vaccination willingness. Willingness was also associated with believing one had never been infected with severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) and experiencing negative pandemic consequences. Safety concerns were most common among those unwilling. Our comprehensive assessment of COVID-19 vaccination willingness among older adults in Canada, a prioritized group for vaccination due to their risk of severe COVID-19 outcomes, provides a road map for conducting outreach to increase uptake, which is urgently needed.


Subject(s)
COVID-19 , Influenza Vaccines , Aged , Aging , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Vaccines , Canada/epidemiology , Cross-Sectional Studies , Female , Humans , Longitudinal Studies , SARS-CoV-2 , Vaccination
4.
Vaccine ; 40(3): 503-511, 2022 01 24.
Article in English | MEDLINE | ID: covidwho-1598441

ABSTRACT

INTRODUCTION: Understanding how influenza vaccine uptake changed during the 2020/2021 influenza season compared to previous pre-pandemic seasons is a key priority, as is identifying the relationship between prior influenza vaccination and COVID-19 vaccine willingness. METHODS: We analyzed data from a large, nationally representative cohort of Canadian residents aged 50 and older to assess influenza vaccination status three times between 2015 and 2020. We investigated: 1) changes in self-reported influenza vaccine uptake, 2) predictors of influenza vaccine uptake in 2020/2021, and 3) the association between influenza vaccination history and self-reported COVID-19 vaccine willingness using logistic regression models. RESULTS: Among 23,385 participants analyzed for aims 1-2, influenza vaccination increased over time: 14,114 (60.4%) in 2015-2018, 15,692 (67.1%) in 2019/2020, and 19,186 (82.0%; combining those already vaccinated and those planning to get a vaccine) in 2020/2021. After controlling for socio-demographics, history of influenza vaccination was most strongly associated with influenza vaccination in 2020/2021 (adjusted odds ratio [aOR] 147.9 [95% CI: 120.9-180.9]); this association remained after accounting for multiple health and pandemic-related factors (aOR 140.3 [95% CI: 114.5-171.8]). To a lesser degree, those more concerned about COVID-19 were also more likely to report influenza vaccination in fall 2020, whereas those reporting a very negative impact of the pandemic were less likely to get vaccinated. Among 23,819 participants with information on COVID-19 vaccine willingness during the last quarter of 2020 (aim 3), prior influenza vaccination was most strongly associated with willingness to get a COVID-19 vaccine (aOR 15.1 [95% CI: 13.5-16.8] for those who had received influenza vaccine at all previous timepoints versus none). CONCLUSIONS: Our analysis highlights the importance of previous vaccination in driving vaccination uptake and willingness. Efforts to increase vaccination coverage for influenza and COVID-19 should target individuals who do not routinely engage with immunization services regardless of demographic factors.


Subject(s)
COVID-19 , Influenza Vaccines , Influenza, Human , Adult , Aged , Aging , COVID-19 Vaccines , Canada/epidemiology , Cross-Sectional Studies , Humans , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Longitudinal Studies , Middle Aged , Pandemics , SARS-CoV-2 , Vaccination
5.
PLoS Med ; 18(7): e1003682, 2021 07.
Article in English | MEDLINE | ID: covidwho-1317138

ABSTRACT

BACKGROUND: We assessed the impact of the coronavirus disease 2019 (COVID-19) epidemic in India on the consumption of antibiotics and hydroxychloroquine (HCQ) in the private sector in 2020 compared to the expected level of use had the epidemic not occurred. METHODS AND FINDINGS: We performed interrupted time series (ITS) analyses of sales volumes reported in standard units (i.e., doses), collected at regular monthly intervals from January 2018 to December 2020 and obtained from IQVIA, India. As children are less prone to develop symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, we hypothesized a predominant increase in non-child-appropriate formulation (non-CAF) sales. COVID-19-attributable changes in the level and trend of monthly sales of total antibiotics, azithromycin, and HCQ were estimated, accounting for seasonality and lockdown period where appropriate. A total of 16,290 million doses of antibiotics were sold in India in 2020, which is slightly less than the amount in 2018 and 2019. However, the proportion of non-CAF antibiotics increased from 72.5% (95% CI: 71.8% to 73.1%) in 2019 to 76.8% (95% CI: 76.2% to 77.5%) in 2020. Our ITS analyses estimated that COVID-19 likely contributed to 216.4 million (95% CI: 68.0 to 364.8 million; P = 0.008) excess doses of non-CAF antibiotics and 38.0 million (95% CI: 26.4 to 49.2 million; P < 0.001) excess doses of non-CAF azithromycin (equivalent to a minimum of 6.2 million azithromycin treatment courses) between June and September 2020, i.e., until the peak of the first epidemic wave, after which a negative change in trend was identified. In March 2020, we estimated a COVID-19-attributable change in level of +11.1 million doses (95% CI: 9.2 to 13.0 million; P < 0.001) for HCQ sales, whereas a weak negative change in monthly trend was found for this drug. Study limitations include the lack of coverage of the public healthcare sector, the inability to distinguish antibiotic and HCQ sales in inpatient versus outpatient care, and the suboptimal number of pre- and post-epidemic data points, which could have prevented an accurate adjustment for seasonal trends despite the robustness of our statistical approaches. CONCLUSIONS: A significant increase in non-CAF antibiotic sales, and particularly azithromycin, occurred during the peak phase of the first COVID-19 epidemic wave in India, indicating the need for urgent antibiotic stewardship measures.


Subject(s)
Anti-Bacterial Agents/economics , Drug Utilization/statistics & numerical data , Hydroxychloroquine/economics , Pandemics/economics , SARS-CoV-2 , Anti-Bacterial Agents/supply & distribution , Anti-Bacterial Agents/therapeutic use , COVID-19/economics , Commerce/statistics & numerical data , Drug Compounding , Drug Utilization/economics , Humans , Hydroxychloroquine/supply & distribution , Hydroxychloroquine/therapeutic use , India , Interrupted Time Series Analysis , Pandemics/statistics & numerical data
6.
Expert Rev Anti Infect Ther ; 20(2): 147-160, 2022 02.
Article in English | MEDLINE | ID: covidwho-1297352

ABSTRACT

INTRODUCTION: Rising rates of antimicrobial resistance (AMR) globally continue to pose agrave threat to human health. Low- and middle-income countries (LMICs) are disproportionately affected, partly due to the high burden of communicable diseases. AREAS COVERED: We reviewed current trends in AMR in LMICs and examined the forces driving AMR in those regions. The state of interventions being undertaken to curb AMR across the developing world are discussed, and the impact of the current COVID-19 pandemic on those efforts is explored. EXPERT OPINION: The dynamics that drive AMR in LMICs are inseparable from the political, economic, socio-cultural, and environmental forces that shape these nations. The COVID-19 pandemic has further exacerbated underlying factors that increase AMR. Some progress is being made in implementing surveillance measures in LMICs, but implementation of concrete measures to meaningfully impact AMR rates must address the underlying structural issues that generate and promote AMR. This, in turn, will require large infrastructural investments and significant political will.


Subject(s)
Anti-Bacterial Agents , Drug Resistance, Bacterial , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , COVID-19 , Developing Countries , Humans , Pandemics
7.
CMAJ ; 192(49): E1734-E1746, 2020 Dec 07.
Article in French | MEDLINE | ID: covidwho-1004486

ABSTRACT

CONTEXTE: Le dépistage du coronavirus du syndrome respiratoire aigu sévère 2 (SRAS-CoV-2) est en grande partie passif, ce qui nuit au contrôle de l'épidémie. Nous avons élaboré des stratégies de dépistage actif du SRAS-CoV-2 au moyen d'une amplification en chaîne par polymérase couplée à une transcription inverse (RT-PCR) chez les groupes courant un risque accru de contracter le virus dans les provinces canadiennes. MÉTHODES: Nous avons identifié 5 groupes qui devraient être prioritaires pour le dépistage actif au moyen d'une RTPCR, soit les gens ayant été en contact avec une personne infectée par le SRAS-CoV-2 et ceux qui appartiennent à 4 populations à risque : employés d'hôpitaux, travailleurs en soins de santé communautaires ainsi qu'employés et résidents d'établissements de soins de longue durée, employés d'entreprises essentielles, et élèves et personnel scolaire. Nous avons estimé les coûts, les ressources humaines et la capacité de laboratoire nécessaires au dépistage des membres de ces groupes ou au dépistage sur des échantillons aléatoires aux fins de surveillance. RÉSULTATS: Du 8 au 17 juillet 2020, 41 751 dépistages par RT-PCR étaient réalisés chaque jour en moyenne dans les provinces canadiennes; nous avons estimé que ces tests mobilisaient 5122 employés et coûtaient 2,4 millions de dollars par jour (67,8 millions de dollars par mois). La recherche et le dépistage systématiques des contacts requerraient 1,2 fois plus de personnel et porteraient les coûts mensuels à 78,9 millions de dollars. S'il était réalisé en 1 mois, le dépistage de tous les employés des hôpitaux nécessiterait 1823 travailleurs supplémentaires et coûterait 29,0 millions de dollars. Pour la même période de temps, le dépistage de tous les travailleurs en soins de santé communautaires et de tous les employés et résidents des établissements de soins de longue durée nécessiterait 11 074 employés supplémentaires et coûterait 124,8 millions de dollars, et celui de tous les travailleurs essentiels nécessiterait 25 965 employés supplémentaires et coûterait 321,7 millions de dollars. Enfin, le dépistage sur 6 semaines de la population scolaire nécessiterait 46 368 employés supplémentaires et coûterait 816,0 millions de dollars. Les interventions visant à pallier les inefficacités, comme le dépistage à partir d'échantillons de salive et le regroupement des échantillons, pourraient réduire les coûts de 40 % et les besoins en personnel, de 20 %. Le dépistage de surveillance sur des échantillons de la population autre que les contacts coûterait 5 % des coûts associés à l'adoption d'une approche universelle de dépistage auprès des populations à risque. INTERPRÉTATION: Le dépistage actif des groupes courant un risque accru de contracter le SRAS-CoV-2 semble faisable et favoriserait la réouverture sûre et à grande échelle de l'économie et des écoles. Cette stratégie semble également abordable lorsque comparée aux 169,2 milliards de dollars versés par le gouvernement fédéral dans la lutte contre la pandémie en date de juin 2020.

8.
CMAJ ; 192(40): E1146-E1155, 2020 10 05.
Article in English | MEDLINE | ID: covidwho-751000

ABSTRACT

BACKGROUND: Testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is largely passive, which impedes epidemic control. We defined active testing strategies for SARS-CoV-2 using reverse transcription polymerase chain reaction (RT-PCR) for groups at increased risk of acquiring SARS-CoV-2 in all Canadian provinces. METHODS: We identified 5 groups who should be prioritized for active RT-PCR testing: contacts of people who are positive for SARS-CoV-2, and 4 at-risk populations - hospital employees, community health care workers and people in long-term care facilities, essential business employees, and schoolchildren and staff. We estimated costs, human resources and laboratory capacity required to test people in each group or to perform surveillance testing in random samples. RESULTS: During July 8-17, 2020, across all provinces in Canada, an average of 41 751 RT-PCR tests were performed daily; we estimated this required 5122 personnel and cost $2.4 million per day ($67.8 million per month). Systematic contact tracing and testing would increase personnel needs 1.2-fold and monthly costs to $78.9 million. Conducted over a month, testing all hospital employees would require 1823 additional personnel, costing $29.0 million; testing all community health care workers and persons in long-term care facilities would require 11 074 additional personnel and cost $124.8 million; and testing all essential employees would cost $321.7 million, requiring 25 965 added personnel. Testing the larger population within schools over 6 weeks would require 46 368 added personnel and cost $816.0 million. Interventions addressing inefficiencies, including saliva-based sampling and pooling samples, could reduce costs by 40% and personnel by 20%. Surveillance testing in population samples other than contacts would cost 5% of the cost of a universal approach to testing at-risk populations. INTERPRETATION: Active testing of groups at increased risk of acquiring SARS-CoV-2 appears feasible and would support the safe reopening of the economy and schools more broadly. This strategy also appears affordable compared with the $169.2 billion committed by the federal government as a response to the pandemic as of June 2020.


Subject(s)
Betacoronavirus/isolation & purification , Clinical Laboratory Techniques/economics , Coronavirus Infections/diagnosis , Coronavirus Infections/economics , Mass Screening/economics , Pandemics/economics , Pneumonia, Viral/diagnosis , Pneumonia, Viral/economics , COVID-19 , COVID-19 Testing , Canada , Coronavirus Infections/epidemiology , Coronavirus Infections/prevention & control , Humans , Pandemics/prevention & control , Pneumonia, Viral/epidemiology , Pneumonia, Viral/prevention & control , Real-Time Polymerase Chain Reaction/economics , Risk Assessment/economics , Risk Factors , SARS-CoV-2
SELECTION OF CITATIONS
SEARCH DETAIL