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1.
Rev Med Virol ; 33(3): e2329, 2023 05.
Article in English | MEDLINE | ID: mdl-35142401

ABSTRACT

The most effective means of preventing seasonal influenza is through vaccination. In this systematic review, we investigated the efficacy, effectiveness and safety of MF59® adjuvanted trivalent and quadrivalent influenza vaccines to prevent laboratory-confirmed influenza. A systematic literature search was conducted in electronic databases and grey literature sources up to 7 February 2020. Randomised controlled trials and non-randomised studies of interventions (NRSIs) were eligible for inclusion. The search returned 28,846 records, of which 48 studies on MF59® adjuvanted vaccines met our inclusion criteria. No efficacy trials were identified. In terms of vaccine effectiveness (VE), MF59® adjuvanted trivalent influenza vaccines were effective in preventing laboratory-confirmed influenza in older adults (aged ≥65 years) compared with no vaccination (VE = 45%, 95% confidence interval (CI) 23%-61%, 5 NRSIs across 3 influenza seasons). By subtype, significant effect was found for influenza A(H1N1) (VE = 61%, 95% CI 44%-73%) and B (VE = 29%, 95% CI 5%-46%), but not for A(H3N2). In terms of relative VE, there was no significant difference comparing MF59® adjuvanted trivalent vaccines with either non-adjuvanted trivalent or quadrivalent vaccines. Compared with traditional trivalent influenza vaccines, MF59® adjuvanted trivalent influenza vaccines were associated with a greater number of local adverse events (RR = 1.90, 95% CI 1.50-2.39) and systemic reactions (RR = 1.18, 95% CI 1.02-1.38). In conclusion, MF59® adjuvanted trivalent influenza vaccines were found to be more effective than 'no vaccination'. Based on limited data, there was no significant difference comparing the effectiveness of MF59® adjuvanted vaccines with their non-adjuvanted counterparts.


Subject(s)
Influenza A Virus, H1N1 Subtype , Influenza Vaccines , Influenza, Human , Adolescent , Aged , Humans , Adjuvants, Immunologic/adverse effects , Antibodies, Viral , Influenza A Virus, H3N2 Subtype , Influenza Vaccines/adverse effects , Influenza, Human/prevention & control , Seasons
2.
Rev Med Virol ; 33(3): e2331, 2023 05.
Article in English | MEDLINE | ID: mdl-35106885

ABSTRACT

The most effective means of preventing seasonal influenza is through vaccination. In this systematic review, we investigated the efficacy, effectiveness and safety of recombinant haemagglutinin (HA) seasonal influenza vaccines to prevent laboratory-confirmed influenza. A systematic literature search was conducted in electronic databases and grey literature sources up to 7 February 2020. Randomised controlled trials and non-randomised studies of interventions were eligible for inclusion. The search returned 28,846 records, of which 10 studies on recombinant HA influenza vaccine met our inclusion criteria. One study found that the quadrivalent recombinant HA influenza vaccine had higher relative vaccine efficacy (rVE) in preventing laboratory-confirmed influenza during the 2014-15 season compared with traditional quadrivalent vaccination in adults aged ≥50 years (rVE = 30%, 95% CI 10%-47%, moderate-certainty evidence). In a subgroup analysis, higher rVE was reported for influenza A (rVE = 36%, 95% CI 14% to 53%), but not for B (non-significant). Another study reported higher efficacy for the trivalent recombinant HA vaccine compared with placebo (VE = 45%, 95% CI 19-63, 1 RCT, low-certainty evidence) in adults aged 18-55 years. With the exception of a higher rate of chills (RR = 1.33, 95% CI 1.03-1.72), the safety profile of recombinant HA vaccines was comparable to that of traditional influenza vaccines. The evidence base for the efficacy and effectiveness of recombinant HA influenza vaccines is limited at present, although one study found that the quadrivalent recombinant HA influenza vaccine had higher rVE compared with traditional quadrivalent vaccination in adults aged ≥50 years.


Subject(s)
Influenza Vaccines , Influenza, Human , Adult , Humans , Adolescent , Influenza, Human/prevention & control , Influenza, Human/drug therapy , Hemagglutinins , Seasons , Vaccination , Vaccines, Synthetic/adverse effects
3.
Rev Med Virol ; 33(3): e2330, 2023 05.
Article in English | MEDLINE | ID: mdl-35119149

ABSTRACT

This review sought to assess the efficacy, effectiveness and safety of high-dose inactivated influenza vaccines (HD-IIV) for the prevention of laboratory-confirmed influenza in individuals aged 18 years or older. A systematic literature search was conducted in electronic databases and grey literature sources up to 7 February 2020. Randomised controlled trials (RCTs) and non-randomised studies of interventions (NRSIs) were included. The search returned 28,846 records, of which 36 studies were included. HD-IIV was shown to have higher relative vaccine efficacy in preventing influenza compared with standard-dose influenza vaccines (SD-IIV3) in older adults (Vaccine effectiveness (VE) = 24%, 95% CI 10-37, one RCT). One NRSI demonstrated significant effect for HD-IIV3 against influenza B (VE = 89%, 95% CI 47-100), but not for influenza A(H3N2) (VE = 22%, 95% CI -82 to 66) when compared with no vaccination in older adults. HD-IIV3 showed significant relative effect compared with SD-IIV3 for influenza-related hospitalisation (VE = 11.8%, 95% CI 6.4-17.0, two NRSIs), influenza- or pneumonia-related hospitalisation (VE = 13.7%, 95% CI 9.5-17.7, three NRSIs), influenza-related hospital encounters (VE = 13.1%, 95% CI 8.4-17.7, five NRSIs), and influenza-related office visits (VE = 3.5%, 95% CI 1.5-5.5, two NRSIs). For safety, HD-IIV were associated with significantly higher rates of local and systemic adverse events compared with SD-IIV (combined local reactions, pain at injection site, swelling, induration, headache, chills and malaise). From limited data, compared with SD-IIV, HD-IIV were found to be more effective in the prevention of laboratory-confirmed influenza, for a range of proxy outcome measures, and associated with more adverse events.


Subject(s)
Influenza Vaccines , Influenza, Human , Adolescent , Aged , Humans , Influenza, Human/prevention & control , Seasons , Vaccination/adverse effects , Vaccines, Inactivated/adverse effects
4.
Cancers (Basel) ; 14(17)2022 Sep 03.
Article in English | MEDLINE | ID: mdl-36077856

ABSTRACT

Human papillomavirus (HPV) infection has been identified as a significant etiological agent in the development of head and neck squamous cell carcinoma (HNSCC). HPV's involvement has alluded to better survival and prognosis in patients and suggests that different treatment strategies may be appropriate for them. Only some data on the epidemiology of HPV infection in the oropharyngeal, oral cavity, and laryngeal SCC exists in Europe. Thus, this study was carried out to investigate HPV's impact on HNSCC patient outcomes in the Irish population, one of the largest studies of its kind using consistent HPV testing techniques. A total of 861 primary oropharyngeal, oral cavity, and laryngeal SCC (OPSCC, OSCC, LSCC) cases diagnosed between 1994 and 2013, identified through the National Cancer Registry of Ireland (NCRI), were obtained from hospitals across Ireland and tested for HPV DNA using Multiplex PCR Luminex technology based in and sanctioned by the International Agency for Research on Cancer (IARC). Both overall and cancer-specific survival were significantly improved amongst all HPV-positive patients together, though HPV status was only a significant predictor of survival in the oropharynx. Amongst HPV-positive patients in the oropharynx, surgery alone was associated with prolonged survival, alluding to the potential for de-escalation of treatment in HPV-related OPSCC in particular. Cumulatively, these findings highlight the need for continued investigation into treatment pathways for HPV-related OPSCC, the relevance of introducing boys into national HPV vaccination programs, and the relevance of the nona-valent Gardasil-9 vaccine to HNSCC prevention.

5.
BMJ Open ; 12(5): e048478, 2022 05 11.
Article in English | MEDLINE | ID: mdl-35545381

ABSTRACT

OBJECTIVE: To conduct a systematic review and meta-analysis of randomised controlled trials (RCTs) of the effectiveness and safety of oral pre-exposure prophylaxis (PrEP) to prevent HIV. METHODS: Databases (PubMed, Embase and the Cochrane Register of Controlled Trials) were searched up to 5 July 2020. Search terms for 'HIV' were combined with terms for 'PrEP' or 'tenofovir/emtricitabine'. RCTs were included that compared oral tenofovir-containing PrEP to placebo, no treatment or alternative medication/dosing schedule. The primary outcome was the rate ratio (RR) of HIV infection using a modified intention-to-treat analysis. Secondary outcomes included safety, adherence and risk compensation. All analyses were stratified a priori by population: men who have sex with men (MSM), serodiscordant couples, heterosexuals and people who inject drugs (PWIDs). The quality of individual studies was assessed using the Cochrane risk-of-bias tool, and the certainty of evidence was assessed using GRADE. RESULTS: Of 2803 unique records, 15 RCTs met our inclusion criteria. Over 25 000 participants were included, encompassing 38 289 person-years of follow-up data. PrEP was found to be effective in MSM (RR 0.25, 95% CI 0.1 to 0.61; absolute rate difference (RD) -0.03, 95% CI -0.01 to -0.05), serodiscordant couples (RR 0.25, 95% CI 0.14 to 0.46; RD -0.01, 95% CI -0.01 to -0.02) and PWID (RR 0.51, 95% CI 0.29 to 0.92; RD -0.00, 95% CI -0.00 to -0.01), but not in heterosexuals (RR 0.77, 95% CI 0.46 to 1.29). Efficacy was strongly associated with adherence (p<0.01). PrEP was found to be safe, but unrecognised HIV at enrolment increased the risk of viral drug resistance mutations. Evidence for behaviour change or an increase in sexually transmitted infections was not found. CONCLUSIONS: PrEP is safe and effective in MSM, serodiscordant couples and PWIDs. Additional research is needed prior to recommending PrEP in heterosexuals. No RCTs reported effectiveness or safety data for other high-risk groups, such as transgender women and sex workers. PROSPERO REGISTRATION NUMBER: CRD42017065937.


Subject(s)
Anti-HIV Agents , HIV Infections , Pre-Exposure Prophylaxis , Anti-HIV Agents/therapeutic use , Emtricitabine/therapeutic use , Female , HIV Infections/drug therapy , HIV Infections/prevention & control , Humans , Male , Tenofovir/therapeutic use , Treatment Outcome
6.
Int J Health Policy Manag ; 11(11): 2464-2475, 2022 12 06.
Article in English | MEDLINE | ID: mdl-35042323

ABSTRACT

BACKGROUND: How research findings are presented through domestic news can influence behaviour and risk perceptions, particularly during emergencies such as the coronavirus disease 2019 (COVID-19) pandemic. Monitoring media communications to track misinformation and find information gaps is an important component of emergency risk communication. Therefore, this study investigated the traditional media coverage of nine selected COVID-19 evidence-based research reports and associated press releases (PRs) published during the initial phases of the pandemic (April to July 2020) by one national agency. METHODS: NVivo was used for summative content analysis. 'Key messages' from each research report were proposed and 488 broadcast, print, and online media sources were coded at the phrase level. Manifest content was coded and counted to locate patterns in the data (what and how many) while latent content was analysed to further investigate these patterns (why and how). This included the coding of the presence of political and public health actors in coverage. RESULTS: Coverage largely did not misrepresent the results of the reports, however, selective reporting and the variability in the use of quotes from governmental and public health stakeholders changed and contextualised results in different manners than perhaps originally intended in the PR. Reports received varying levels of media attention. Coverage focused on more 'human-interest' stories (eg, spread of COVID-19 by children and excess mortality) as opposed to more technical reports (eg, focusing on viral load, antibodies, testing, etc). CONCLUSION: Our findings provide a case-study of European media coverage of evidence reports produced by a national agency. Results highlighted several strengths and weaknesses of current communication efforts.


Subject(s)
COVID-19 , Social Media , Child , Humans , COVID-19/epidemiology , Research Report , Communication , Public Health , Pandemics
7.
Rev Med Virol ; 32(3): e2299, 2022 05.
Article in English | MEDLINE | ID: mdl-34582072

ABSTRACT

The aim of this rapid review was to determine the effectiveness of pharmacological interventions (excluding vaccines) to prevent coronavirus disease 2019 (Covid-19) or reduce the severity of disease. A systematic search of published peer-reviewed articles and non-peer-reviewed pre-prints was undertaken from 1 January 2020 to 17 August 2021. Four randomised controlled trials (RCTs) and one non-RCT were included; three trials (two RCTs and one non-RCT) tested ivermectin with or without carrageenan. While all reported some potential protective effect of ivermectin, these trials had a high risk of bias and the certainty of evidence was deemed to be 'very low'. One RCT tested bamlanivimab compared to placebo and reported a significantly reduced incidence of Covid-19 in the intervention group; this trial had a low risk of bias however the certainty of evidence was deemed 'very low'. The fifth RCT tested casirivimab plus imdevimab versus placebo and reported that the combination of monoclonal antibodies significantly reduced the incidence of symptomatic and asymptomatic SARS-CoV-2 infection, viral load, duration of symptomatic disease and the duration of a high viral load; this trial was deemed to have a low risk of bias, and the certainty of evidence was 'low'. The designations 'low' and 'very low' regarding the certainty of evidence indicate that the estimate of effect is uncertain and therefore is unsuitable for informing decision-making. At the time of writing, there is insufficient high quality evidence to support the use of pharmacological interventions to prevent Covid-19.


Subject(s)
COVID-19 Drug Treatment , COVID-19 , Antibodies, Monoclonal, Humanized , Antibodies, Neutralizing , COVID-19/prevention & control , Humans , Ivermectin/therapeutic use , SARS-CoV-2
8.
Ann Pharmacother ; 56(3): 309-318, 2022 03.
Article in English | MEDLINE | ID: mdl-34157890

ABSTRACT

OBJECTIVE: To conduct a systematic review on the effectiveness and safety of pharmacological and nonpharmacological interventions, in the ambulatory setting, aimed at preventing severe disease in patients with COVID-19. DATA SOURCES: Electronic databases (PubMed, EMBASE, and EuropePMC) were searched on January 6, 2021. STUDY SELECTION AND DATA EXTRACTION: A systematic review was conducted, adhering to PRISMA guidelines. The quality of individual trials was assessed using the Cochrane Risk-of-Bias Tool 2, and the certainty of evidence was assessed using GRADE. DATA SYNTHESIS: The collective search retrieved 3818 citations. Eight trials relating to 9 pharmacological interventions were identified. No evidence for nonpharmacological interventions was identified. Low certainty evidence of effectiveness in preventing severe disease was found for fluvoxamine (absolute difference: -8.7%; 95% CI: -1.8% to -16.4%) and bamlanivimab plus etesevimab (absolute difference: -4.9%; 95% CI: -0.8% to -8.9%). Both trials were limited by small sample sizes and short durations of follow-up. In addition, very low certainty evidence of effect was found for ivermectin plus doxycycline and sulodexide. Based on published data, insufficient evidence of effect was found for bamlanivimab (monotherapy), casirivimab plus imdevimab, ivermectin (monotherapy), nitazoxanide, and peginterferon lambda. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: This review assessed all ambulatory treatments for COVID-19 that may improve patient outcomes and reduce hospitalizations. CONCLUSION: Recent trials have shown promising results for a number of pharmacological agents to treat COVID-19 in the ambulatory setting. However, larger, more robust trials are needed to support the routine use of these agents outside of monitored clinical trials.


Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Antiviral Agents/therapeutic use , COVID-19 , Ambulatory Care , Antibodies, Neutralizing , COVID-19/therapy , Disease Progression , Humans , Interferons , Ivermectin , Nitro Compounds , Polyethylene Glycols , Thiazoles
9.
Rev Med Virol ; 32(1): e2260, 2022 01.
Article in English | MEDLINE | ID: mdl-34043841

ABSTRACT

Despite over 140 million SARS-CoV-2 infections worldwide since the beginning of the pandemic, relatively few confirmed cases of SARS-CoV-2 reinfection have been reported. While immunity from SARS-CoV-2 infection is probable, at least in the short term, few studies have quantified the reinfection risk. To our knowledge, this is the first systematic review to synthesise the evidence on the risk of SARS-CoV-2 reinfection over time. A standardised protocol was employed, based on Cochrane methodology. Electronic databases and preprint servers were searched from 1 January 2020 to 19 February 2021. Eleven large cohort studies were identified that estimated the risk of SARS-CoV-2 reinfection over time, including three that enrolled healthcare workers and two that enrolled residents and staff of elderly care homes. Across studies, the total number of PCR-positive or antibody-positive participants at baseline was 615,777, and the maximum duration of follow-up was more than 10 months in three studies. Reinfection was an uncommon event (absolute rate 0%-1.1%), with no study reporting an increase in the risk of reinfection over time. Only one study estimated the population-level risk of reinfection based on whole genome sequencing in a subset of patients; the estimated risk was low (0.1% [95% CI: 0.08-0.11%]) with no evidence of waning immunity for up to 7 months following primary infection. These data suggest that naturally acquired SARS-CoV-2 immunity does not wane for at least 10 months post-infection. However, the applicability of these studies to new variants or to vaccine-induced immunity remains uncertain.


Subject(s)
COVID-19 , Reinfection , SARS-CoV-2 , Aged , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19 Vaccines , Humans , Pandemics
10.
Value Health ; 24(7): 948-956, 2021 07.
Article in English | MEDLINE | ID: mdl-34243838

ABSTRACT

OBJECTIVES: To estimate the cost-effectiveness of introducing a publicly funded pre-exposure prophylaxis (PrEP) program in Ireland. METHODS: We constructed a state-transition Markov model. This was a cross-sectional population model that tracked all HIV-negative men who have sex with men (MSM) in Ireland over their lifetime. Access to a publicly funded PrEP program (medications + frequent monitoring) in high-risk MSM was compared with no PrEP. The primary outcome measure was the incremental cost-effectiveness ratio (ICER). RESULTS: In the base case, introducing a PrEP program was considered cost saving and provided significant health benefits to the population. Univariate sensitivity analysis demonstrated that PrEP efficacy and HIV incidence had the greatest impact on cost-effectiveness. Including an increase in sexually transmitted infections had a negligible impact on the results. Efficacy was a significant driver in the model. PrEP was cost saving at all efficacy values above 60%, and at the lowest reported efficacy in MSM (44% in the iPrEX trial), the ICER was €4711/QALY (highly cost-effective). Event-based dosing (administration during high-risk periods only) was associated with additional cost savings. We estimated that 1705 individuals (95% CI: 617-3452) would join the program in year 1. The incremental budget impact was €1.5m (95% CI: €0.5m to €3m) in the first year and €5.4m over 5 years (95% CI: €1.8m to €11.5m), with 173 cases of HIV averted over 5 years. CONCLUSION: We found that the introduction of a PrEP program would be considered cost saving in the first cost-effectiveness analysis of its kind in Ireland.


Subject(s)
Cost-Benefit Analysis , HIV Infections/prevention & control , Pre-Exposure Prophylaxis/economics , Cross-Sectional Studies , Homosexuality, Male , Humans , Ireland , Male , Markov Chains
12.
Rev Med Virol ; 31(2): e2162, 2021 03.
Article in English | MEDLINE | ID: mdl-32964627

ABSTRACT

In this review, we systematically searched and summarized the evidence on the immune response and reinfection rate following SARS-CoV-2 infection. We also retrieved studies on SARS-CoV and MERS-CoV to assess the long-term duration of antibody responses. A protocol based on Cochrane rapid review methodology was adhered to and databases were searched from 1/1/2000 until 26/5/2020. Of 4744 citations retrieved, 102 studies met our inclusion criteria. Seventy-four studies were retrieved on SARS-CoV-2. While the rate and timing of IgM and IgG seroconversion were inconsistent across studies, most seroconverted for IgG within 2 weeks and 100% (N = 62) within 4 weeks. IgG was still detected at the end of follow-up (49-65 days) in all patients (N = 24). Neutralizing antibodies were detected in 92%-100% of patients (up to 53 days). It is not clear if reinfection with SARS-CoV-2 is possible, with studies more suggestive of intermittent detection of residual RNA. Twenty-five studies were retrieved on SARS-CoV. In general, SARS-CoV-specific IgG was maintained for 1-2 years post-infection and declined thereafter, although one study detected IgG up to 12 years post-infection. Neutralizing antibodies were detected up to 17 years in another study. Three studies on MERS-CoV reported that IgG may be detected up to 2 years. In conclusion, limited early data suggest that most patients seroconvert for SARS-CoV-2-specific IgG within 2 weeks. While the long-term duration of antibody responses is unknown, evidence from SARS-CoV studies suggest SARS-CoV-specific IgG is sustained for 1-2 years and declines thereafter.


Subject(s)
COVID-19/immunology , Coronavirus Infections/immunology , Coronavirus/immunology , Immunity/immunology , SARS-CoV-2/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Humans , Immunoglobulin G/immunology , Immunoglobulin M/immunology
13.
J Clin Virol Plus ; 1(1): 100015, 2021 Jun.
Article in English | MEDLINE | ID: mdl-35262003

ABSTRACT

Background: In recent months, multiple cases of confirmed SARS-CoV-2 reinfection have been reported. However, accurate epidemiological and virological data, including genomic analysis where possible, are required to differentiate cases of prolonged viral RNA shedding (i.e. intermittent detection) from true reinfection. The objective of this review was to systematically identify and summarise all cases of SARS-CoV-2 reinfection confirmed by comparative genomic analysis. Methods: A protocol based on Cochrane rapid review methodology was employed. Databases and pre-print servers were searched until 9/11/2020. Results: Ten studies, representing 17 patients, were identified (mean age=40; 71% male). The time interval between primary infection and reinfection ranged from 13 to 142 days (median: 60).Comparative whole genome sequencing confirmed reinfection in 14 patients (the primary and secondary infections were caused by different viruses). A further three cases had strong, but not confirmed evidence of reinfection, as only partial genomes were retrieved on primary infection.Across 12 studies that reported the number of single nucleotide polymorphisms (SNPs) comparing the first and second genomes, between 8 and 24 SNPs were discovered. With an average SARS-CoV-2 mutation acquisition rate of 1-2 per month, in all cases it is likely that the secondary infection was caused by a different SARS-CoV-2 virus, rather than prolonged shedding of viral RNA from the primary infection.In five reinfection cases, the primary and secondary infections were caused by different SARS-CoV-2 lineages/clades, strongly indicating that infections were caused by different viruses. Conclusion: Comparative genomic analyses from 14 patients confirm that SARS-CoV-2 reinfection can occur.

14.
Rev Med Virol ; 31(3): e2184, 2021 05.
Article in English | MEDLINE | ID: mdl-33105071

ABSTRACT

A key consideration in the Covid-19 pandemic is the dominant modes of transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. The objective of this review was to synthesise the evidence for the potential airborne transmission of SARS-CoV-2 via aerosols. Systematic literature searches were conducted in PubMed, Embase, Europe PMC and National Health Service UK evidence up to 27 July 2020. A protocol was published and Cochrane guidance for rapid review methodology was adhered to throughout. Twenty-eight studies were identified. Seven out of eight epidemiological studies suggest aerosol transmission may occur, with enclosed environments and poor ventilation noted as possible contextual factors. Ten of the 16 air sampling studies detected SARS-CoV-2 ribonucleic acid; however, only three of these studies attempted to culture the virus with one being successful in a limited number of samples. Two of four virological studies using artificially generated aerosols indicated that SARS-CoV-2 is viable in aerosols. The results of this review indicate there is inconclusive evidence regarding the viability and infectivity of SARS-CoV-2 in aerosols. Epidemiological studies suggest possible transmission, with contextual factors noted. Viral particles have been detected in air sampling studies with some evidence of clinical infectivity, and virological studies indicate these particles may represent live virus, adding further plausibility. However, there is uncertainty as to the nature and impact of aerosol transmission of SARS-CoV-2, and its relative contribution to the Covid-19 pandemic compared with other modes of transmission.


Subject(s)
Aerosols/analysis , COVID-19/transmission , RNA, Viral/isolation & purification , SARS-CoV-2/physiology , COVID-19/epidemiology , COVID-19/pathology , COVID-19/virology , Humans , Retrospective Studies , SARS-CoV-2/pathogenicity , Uncertainty
15.
J Infect ; 81(3): 357-371, 2020 09.
Article in English | MEDLINE | ID: mdl-32615199

ABSTRACT

OBJECTIVES: To summarise the evidence on the detection pattern and viral load of SARS-CoV-2 over the course of an infection (including any asymptomatic or pre-symptomatic phase), and the duration of infectivity. METHODS: A systematic literature search was undertaken in PubMed, Europe PubMed Central and EMBASE from 30 December 2019 to 12 May 2020. RESULTS: We identified 113 studies conducted in 17 countries. The evidence from upper respiratory tract samples suggests that the viral load of SARS-CoV-2 peaks around symptom onset or a few days thereafter, and becomes undetectable about two weeks after symptom onset; however, viral loads from sputum samples may be higher, peak later and persist for longer. There is evidence of prolonged virus detection in stool samples, with unclear clinical significance. No study was found that definitively measured the duration of infectivity; however, patients may not be infectious for the entire duration of virus detection, as the presence of viral ribonucleic acid may not represent transmissible live virus. CONCLUSION: There is a relatively consistent trajectory of SARS-CoV-2 viral load over the course of COVID-19 from respiratory tract samples, however the duration of infectivity remains uncertain.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/virology , Pneumonia, Viral/virology , Viral Load , Adult , Asymptomatic Infections/epidemiology , COVID-19 , Child , Coronavirus Infections/epidemiology , Feces/virology , Humans , Limit of Detection , Pandemics , Pneumonia, Viral/epidemiology , RNA, Viral , SARS-CoV-2 , Severity of Illness Index , Sputum/virology , Time Factors , Virus Shedding
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