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Background: Face masks have been proposed as an important way of reducing transmission of viral respiratory infections, including SARS-CoV-2. Objective: To assess the likelihood that wearing face masks in community settings reduces transmission of viral respiratory infections. Methods: We conducted a rapid evidence review and used a Bayesian statistical approach to analysing experimental and observational studies conducted in community-dwelling children and adults that assessed the effectiveness of face mask wearing (vs. no face masks) on self-reported, laboratory-confirmed, or clinically diagnosed viral respiratory infections. Results: Eleven RCTs and 10 observational studies met the inclusion criteria. The calculation of Bayes factors and cumulative posterior odds from the RCTs showed a moderate likelihood of a small effect of wearing surgical face masks in community settings in reducing self-reported influenza-like illness (ILI) (cumulative posterior odds = 3.61). However, the risk of reporting bias was high and evidence of reduction of clinically- or laboratory-confirmed infection was equivocal (cumulative posterior odds = 1.07 and 1.22, respectively). Observational studies yielded evidence of a negative association between face mask wearing and ILI but with high risk of confounding and reporting bias. Conclusions: Available evidence from RCTs is equivocal as to whether or not wearing face masks in community settings results in a reduction in clinically- or laboratory-confirmed viral respiratory infections. No relevant studies concerned SARS-CoV-2 or were undertaken in community settings in the UK.
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AIMS: To estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19 disease. DESIGN: Living rapid review of observational and experimental studies with random-effects hierarchical Bayesian meta-analyses. Published articles and pre-prints were identified via MEDLINE and medRxiv. SETTING: Community or hospital. No restrictions on location. PARTICIPANTS: Adults who received a SARS-CoV-2 test or a COVID-19 diagnosis. MEASUREMENTS: Outcomes were SARS-CoV-2 infection, hospitalisation, disease severity and mortality stratified by smoking status. Study quality was assessed (i.e. ‘good', ‘fair' and ‘poor'). FINDINGS: v11 (searches up to 2021-02-16) included 405 studies with 62 ‘good' and ‘fair' quality studies included in unadjusted meta-analyses. 121 studies (29.9%) reported current, former and never smoking status with the remainder using broader categories. Recorded smoking prevalence among people with COVID-19 was generally lower than national prevalence. Current compared with never smokers were at reduced risk of SARS-CoV-2 infection (RR = 0.71, 95% Credible Interval (CrI) = 0.61-0.82, τ = 0.34). Data for former smokers were inconclusive (RR = 1.03, 95% CrI = 0.95-1.11, τ = 0.17) but favoured there being no important association (4% probability of RR ≥1.1). Former compared with never smokers were at increased risk of hospitalisation (RR = 1.19, CrI = 1.1-1.29, τ = 0.13), greater disease severity (RR = 1.8, CrI = 1.27-2.55, τ = 0.46) and mortality (RR = 1.56, CrI = 1.23-2, τ = 0.43). Data for current smokers on hospitalisation, disease severity and mortality were inconclusive (RR = 1.1, 95% CrI = 0.99-1.21, τ = 0.15;RR 1.26, 95% CrI = 0.92-1.73, τ = 0.32;RR = 1.12, 95% CrI = 0.84-1.47, τ = 0.42, respectively) but favoured there being no important associations with hospitalisation and mortality (49% and 56% probability of RR ≥1.1, respectively) and a small but important association with disease severity (83% probability of RR ≥1.1). CONCLUSIONS: Compared with never smokers, current smokers appear to be at reduced risk of SARS-CoV-2 infection while former smokers appear to be at increased risk of hospitalisation, greater disease severity and mortality from COVID-19. However, it is uncertain whether these associations are causal. v7 of this living review article has been published in _Addiction_ [https://doi-org.libproxy.ucl.ac.uk/10.1111/add.15276]
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AIMS: To estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19 disease. DESIGN: Living rapid review of observational and experimental studies with random-effects hierarchical Bayesian meta-analyses. Published articles and pre-prints were identified via MEDLINE and medRxiv. SETTING: Community or hospital. No restrictions on location. PARTICIPANTS: Adults who received a SARS-CoV-2 test or a COVID-19 diagnosis. MEASUREMENTS: Outcomes were SARS-CoV-2 infection, hospitalisation, disease severity and mortality stratified by smoking status. Study quality was assessed (i.e. ‘good', ‘fair' and ‘poor'). FINDINGS: Version 10 (searches up to 15 December 2020) included 345 studies with 52 ‘good' and ‘fair' quality studies included in unadjusted meta-analyses. One-hundred-and-one studies (29.3%) reported current, former and never smoking status with the remainder using broader categories. Recorded smoking prevalence among people with COVID-19 was generally lower than national prevalence. Current compared with never smokers were at reduced risk of SARS-CoV-2 infection (RR = 0.69, 95% Credible Interval (CrI) = 0.58-0.82, τ = 0.36). Data for former smokers were inconclusive (RR = 1.03, 95% CrI = 0.94-1.13, τ = 0.18) but favoured there being no important association (8% probability of RR ≥1.1). Former compared with never smokers were at increased risk of hospitalisation (RR = 1.18, CrI = 1.07-1.31, τ = 0.14), greater disease severity (RR = 1.52, CrI = 1.12-2.06, τ = 0.29) and mortality (RR = 1.40, 95% CrI = 1.20-1.64, τ = 0.19). Data for current smokers on hospitalisation, disease severity and mortality were inconclusive (RR = 1.08, CrI = 0.95-1.23, τ = 0.18;RR = 1.26, CrI = 0.85-1.93, τ = 0.34;RR = 1.05, 95% CrI = 0.77-1.41, τ = 0.39, respectively) but favoured there being no important associations with hospitalisation and mortality (31% and 38% probability of RR ≥1.1, respectively) and a small but important association with disease severity (80% probability of RR ≥1.1). CONCLUSIONS: Compared with never smokers, current smokers appear to be at reduced risk of SARS-CoV-2 infection while former smokers appear to be at increased risk of hospitalisation, greater disease severity and mortality from COVID-19. However, it is uncertain whether these associations are causal. v7 of this living review article has been published in _Addiction _and is available here https://doi-org.libproxy.ucl.ac.uk/10.1111/add.15276
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AIMS: To estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19 disease. DESIGN: Living rapid review of observational and experimental studies with random-effects hierarchical Bayesian meta-analyses. Published articles and pre-prints were identified via MEDLINE and medRxiv. SETTING: Community or hospital. No restrictions on location. PARTICIPANTS: Adults who received a SARS-CoV-2 test or a COVID-19 diagnosis. MEASUREMENTS: Outcomes were SARS-CoV-2 infection, hospitalisation, disease severity and mortality stratified by smoking status. Study quality was assessed (i.e. ‘good', ‘fair' and ‘poor'). FINDINGS: v11 (searches up to 2021-02-16) included 405 studies with 62 ‘good' and ‘fair' quality studies included in unadjusted meta-analyses. 121 studies (29.9%) reported current, former and never smoking status with the remainder using broader categories. Recorded smoking prevalence among people with COVID-19 was generally lower than national prevalence. Current compared with never smokers were at reduced risk of SARS-CoV-2 infection (RR = 0.71, 95% Credible Interval (CrI) = 0.61-0.82, τ = 0.34). Data for former smokers were inconclusive (RR = 1.03, 95% CrI = 0.95-1.11, τ = 0.17) but favoured there being no important association (4% probability of RR ≥1.1). Former compared with never smokers were at increased risk of hospitalisation (RR = 1.19, CrI = 1.1-1.29, τ = 0.13), greater disease severity (RR = 1.8, CrI = 1.27-2.55, τ = 0.46) and mortality (RR = 1.56, CrI = 1.23-2, τ = 0.43). Data for current smokers on hospitalisation, disease severity and mortality were inconclusive (RR = 1.1, 95% CrI = 0.99-1.21, τ = 0.15;RR 1.26, 95% CrI = 0.92-1.73, τ = 0.32;RR = 1.12, 95% CrI = 0.84-1.47, τ = 0.42, respectively) but favoured there being no important associations with hospitalisation and mortality (49% and 56% probability of RR ≥1.1, respectively) and a small but important association with disease severity (83% probability of RR ≥1.1). CONCLUSIONS: Compared with never smokers, current smokers appear to be at reduced risk of SARS-CoV-2 infection while former smokers appear to be at increased risk of hospitalisation, greater disease severity and mortality from COVID-19. However, it is uncertain whether these associations are causal. v7 of this living review article has been published in _Addiction_ [https://doi-org.libproxy.ucl.ac.uk/10.1111/add.15276]
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AIMS: To estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity in hospitalised patients, and iv) mortality from SARS-CoV-2/COVID-19 disease. DESIGN: Living rapid review of observational and experimental studies with random-effects hierarchical Bayesian meta-analyses. Published articles and pre-prints were identified via MEDLINE and medRxiv . SETTING: Community or hospital. No restrictions on location. PARTICIPANTS: Adults who received a SARS-CoV-2 test or a COVID-19 diagnosis. MEASUREMENTS: Outcomes were SARS-CoV-2 infection, hospitalisation, disease severity and mortality stratified by smoking status. Study quality was assessed (i.e. ‘good,' ‘fair' and ‘poor'). FINDINGS: v12 (searches up to 2021-07-18) included 547 studies with 87 ‘good' and ‘fair' quality studies included in unadjusted meta-analyses. 171 studies (31.3%) reported current, former and never smoking status with the remainder using broader categories. Recorded smoking prevalence among people with COVID-19 was generally lower than national prevalence. Current compared with never smokers were at reduced risk of SARS-CoV-2 infection (RR = 0.67, 95% Credible Interval (CrI) = 0.60-0.75, τ = 0.27). Data for former smokers were inconclusive (RR = 0.99, 95% CrI = 0.94-1.05, τ = 0.12) but favoured there being no important association (<1% probability of RR ≥1.1). Former compared with never smokers were at increased risk of hospitalisation (RR = 1.27, CrI = 1.15-1.40, τ = 0.20), greater disease severity (RR = 1.69, CrI = 1.30-2.22, τ = 0.43) and mortality (RR = 1.59, CrI = 1.34-1.89, τ = 0.37). Current compared with never smokers were at increased risk of greater disease severity (RR 1.3, 95% CrI = 1.01-1.71, τ = 0.32). Data for current smokers on hospitalisation and mortality were inconclusive (RR = 1.10, 95% CrI = 0.97-1.24, τ = 0.23;RR = 1.13, 95% CrI = 0.90-1.40, τ = 0.41, respectively) but favoured there being no important associations (50% and 60% probability of RR ≥1.1, respectively). CONCLUSIONS: Compared with never smokers, current smokers appear to be at reduced risk of SARS-CoV-2 infection and increased risk of greater in-hospital disease severity, while former smokers appear to be at increased risk of hospitalisation, greater in-hospital disease severity and mortality from COVID-19. However, it is uncertain whether these associations are causal. This version (v12) will be the last regular update;however, yearly updates may continue as new evidence becomes available. v7 of this living review article has been published in _Addiction_ [https://doi.org/10.1111/add.15276]
ABSTRACT
Background: SARS-CoV-2 is the causative agent of COVID-19, an emergent zoonotic disease which has reached pandemic levels and is designated a public health emergency of international concern. It is plausible that former or current smoking status are associated with infection, hospitalisation and/or mortality from COVID-19. Objective: We aimed to estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19. Methods: We adopted recommended practice for rapid evidence reviews, which involved limiting the search to main databases and having one reviewer extract data and another verify. Published articles and pre-prints were identified via Ovid MEDLINE, medRxiv and expertise within the review team. We included observational studies with community-dwelling or hospitalised adults aged 16 years who had been tested for SARS-CoV-2 infection or diagnosed with COVID-19, providing that data on smoking status were reported. The National Institutes of Health's Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies was used to divide studies into ‘good', ‘fair' and ‘poor' quality to address objectives of this review. Studies were judged as ‘good' quality if they: i) had low levels of missing data on smoking status, ii) used a reliable self-report measure that distinguished between current, former and never smoking status, iii) used biochemical verification of smoking status and iv) adjusted analyses for potential confounding variables. Results: Sixty-seven studies were included, 30 of which were conducted in China, 12 in the US, six in the UK, four in France, three in Mexico, three in Spain, two across multiple international sites, two in Italy, and one each from Iran, Israel, Korea, Kuwait and Switzerland. Eleven studies did not state the source for information on smoking status. Fifty-one studies reported current and/or former smoking status but had high levels of missing data and/or did not explicitly state whether the remaining participants were never smokers. Notwithstanding recording uncertainties, compared with national prevalence estimates, recorded current and former smoking rates in most studies were lower than expected. In six ‘fair' quality studies, no significant difference was observed between current and never (RR = 0.78, 95% CI = 0.55-1.11, p = .17, I2 = 92%) or former and never smokers (RR = 1.07, 95% CI = 0.95-1.20, p = .24, I2 = 61%) in the risk of testing positive for SARS-CoV-2. In five ‘fair' quality studies, there was no significant difference between current and never (RR = 1.12, 95% CI = 0.74-1.69, p = .48, I2 = 84%) or former and never smokers (RR = 1.21, 95% CI = 0.82-1.79, p = .24, I2 = 81%) in the risk of requiring admission to hospital following diagnosis of COVID-19. In three ‘fair' quality studies, current smokers were at increased risk of greater disease severity compared with never smokers (RR = 1.37, 95% CI = 1.07-1.75, p = .01, I2 = 0%). No significant difference was observed between former and never smokers (RR = 1.51, 95% CI = 0.82-2.80, p = .19, I2 = 81%). In three ‘fair' quality studies, there were inconsistent results on mortality from COVID-19 in current and former compared with never smokers. Conclusions: Across 67 observational studies, there is substantial uncertainty about the associations between smoking and COVID-19 outcomes. The recorded smoking prevalence in hospitalised patients was lower than national estimates but this observation is inconsistent with there being no evidence of increased admission to hospital from five ‘fair' quality studies of people who tested positive. There was limited evidence from ‘fair' quality studies that current compared with never smoking is associated with greater disease severity in those hospitalised for COVID-19. Implications: Unrelated to COVID-19, smokers are at a greater risk of a range of serious health problems, requiring them to be admitt d to hospital. Given uncertainty around the association of smoking with COVID-19, smoking cessation remains a public health priority and high-quality smoking cessation advice including recommendations to use alternative nicotine should form part of public health efforts during this pandemic.
ABSTRACT
Background: SARS-CoV-2 is the causative agent of COVID-19, an emergent zoonotic disease which has reached pandemic levels and is designated a public health emergency of international concern. It is plausible that former or current smoking status are risk factors for infection, hospitalisation and/or mortality from COVID-19. Objective: We aimed to estimate the rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19 stratified by smoking status. Methods: We adopted recommended practice for rapid evidence reviews, which involved limiting the search to main databases and having one reviewer extract data and another verify. Published articles and pre-prints were identified via MEDLINE, EPPI-Mapper and expertise within the review team. We included observational studies with community-dwelling or hospitalised adults aged 16 years who had been tested for SARS-CoV-2 or were diagnosed with COVID-19, providing that data on smoking status were reported. Studies were judged as high quality if they explicitly recorded current, former and never smoking status with low levels of missing data. Results: Twenty-eight studies were included, 22 of which were conducted in China, three in the US, one in Korea, one in France and one across multiple international sites with data predominantly collected in the UK. Eight studies did not state the source for information on smoking status. Twenty-five studies reported current and/or former smoking status but had high levels of missing data and/or did not explicitly state whether the remaining participants were never smokers. Notwithstanding these uncertainties, compared with national prevalence estimates, recorded current and former smoking rates in the included studies were generally lower than expected. Within the only study to report community SARS-CoV-2 infection by smoking status, current smokers appeared more likely to be tested but the rate for positive tests was lower. In two high-quality studies, results from a fixed-effects meta-analysis provided no evidence for an increased risk of hospitalisation among 657 current/former smokers who tested positive in the community (RR = 1.03, 95% CI = 0.93-1.14, p = 0.57). Among 1370 people hospitalised across two high-quality studies, there was greater disease severity in current/former smokers compared with never smokers (RR = 1.43, 95% CI = 1.15-1.77, p = .002). Three studies reporting on mortality did not explicitly state never smoking status. Conclusions: Across 28 observational studies, there is substantial uncertainty arising from the recording of smoking status on whether current and/or former smoking status is associated with SARS-CoV-2 infection, hospitalisation or mortality. There is low quality evidence that current and former smoking compared with never is associated with greater disease severity in those hospitalised for COVID-19. Implications: Unrelated to COVID-19, smokers are at a greater risk of a range of serious health problems requiring them to be admitted to hospital. Given uncertainty around the association of smoking with COVID-19, smoking cessation remains a public health priority and high-quality smoking cessation advice should form part of public health efforts during this pandemic.
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Aims: : To estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19 disease. Design: Living rapid review of observational and experimental studies with random-effects hierarchical Bayesian meta-analyses. Published articles and pre-prints were identified via Ovid MEDLINE and medRxiv. Setting: Community or hospital with no restrictions on location. Participants: Adults who had received a test for SARS-CoV-2 infection or a diagnosis of COVID-19. Measurements: Outcomes were SARS-CoV-2 infection, hospitalisation, disease severity and mortality stratified by smoking status. Study quality was assessed. Findings: Version 6 with searches up to 17 July 2020 included 174 studies with 26 included in meta-analyses. Thirty-nine studies reported current, former and never smoking status. Notwithstanding recording uncertainties, compared with adult national prevalence estimates, recorded current smoking rates were generally lower than expected. Current compared with never smokers were at reduced risk of SARS-CoV-2 infection (RR = 0.74, 95% Credible Interval (CrI) = 0.56-0.97, τ = 0.46). Former compared with never smokers were at somewhat increased risk of infection but data were inconclusive (RR = 1.06, 95% CrI = 0.94-1.20, τ = 0.19). Current (RR = 1.05, CrI = 0.82-1.34, τ = 0.29) and former (RR = 1.20, CrI = 1.03-1.44, τ = 0.19) compared with never smokers were both at somewhat increased risk of hospitalisation with COVID-19, but data for current smokers were inconclusive. Current (RR = 1.15, CrI = 0.80-1.66, τ = 0.29) and former (RR = 1.51, CrI = 1.06-2.15, τ = 0.36) compared with never smokers were at increased risk of greater disease severity, but data for current smokers were inconclusive. Current (RR = 1.89, 95% CrI = 0.77-3.41, τ = 0.51) and former (RR = 1.93, 95% CrI = 1.33-2.66, τ = 0.19) compared with never smokers had increased risk of in-hospital death, but data for current smokers were inconclusive. Conclusions: There is uncertainty about the associations of smoking with COVID-19 outcomes. Recorded smoking prevalence among people with COVID-19 was generally lower than national prevalence. Current smokers were at reduced risk of infection. Former smokers were at increased risk of hospitalisation, disease severity and mortality, while data for current smokers favoured no important associations but were inconclusive.
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Aims: : To estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19 disease. Design: Living rapid review of observational and experimental studies with random-effects hierarchical Bayesian meta-analyses. Published articles and pre-prints were identified via MEDLINE and medRxiv. Setting: Community or hospital. No restrictions on location. Participants: Adults who received a SARS-CoV-2 test or a COVID-19 diagnosis. Measurements: Outcomes were SARS-CoV-2 infection, hospitalisation, disease severity and mortality stratified by smoking status. Study quality was assessed (i.e. ‘good', ‘fair' and ‘poor'). Findings: Version 8 (searches up to 22 September 2020) included 256 studies with 36 ‘good' and ‘fair' quality studies included in meta-analyses. Sixty-seven studies (26.2%) reported current, former and never smoking status with the remainder using broader categories. Recorded smoking prevalence among people with COVID-19 was generally lower than national prevalence. Current compared with never smokers were at reduced risk of SARS-CoV-2 infection (RR=0.72, 95% Credible Interval (CrI) = 0.57-0.89, τ = 0.40). Data for former smokers were inconclusive (RR=1.02, 95% CrI = 0.92-1.13, τ = 0.18) but favoured there being no important association (7% probability of RR ≥1.1). Former compared with never smokers were at somewhat increased risk of hospitalisation (RR=1.19, CrI = 1.03-1.43, τ = 0.17), greater disease severity (RR=1.52, CrI = 1.12-2.05, τ = 0.29) and mortality (RR=1.35, 95% CrI = 1.09-1.73, τ = 0.26). Data for current smokers on hospitalisation, disease severity and mortality were inconclusive (RR=1.06, CrI = 0.82-1.35, τ = 0.27;RR=1.26, CrI = 0.85-1.96, τ = 0.34;RR=1.10, 95% CrI = 0.69-1.67, τ = 0.50, respectively) but favoured there being no important associations with hospitalisation and mortality (35% and 51% probability of RR ≥1.1, respectively) and a small but important association with disease severity (79% probability of RR ≥1.1). Conclusions: Compared with never smokers, current smokers appear to be at reduced risk of SARS-CoV-2 infection while former smokers appear to be at increased risk of hospitalisation, greater disease severity and mortality from COVID-19. However, it is uncertain whether these associations are causal.
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Aims: : To estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19 disease. Design: Living rapid review of observational and experimental studies with random-effects hierarchical Bayesian meta-analyses. Published articles and pre-prints were identified via MEDLINE and medRxiv. Setting: Community or hospital. No restrictions on location. Participants: Adults who received a SARS-CoV-2 test or a COVID-19 diagnosis. Measurements: Outcomes were SARS-CoV-2 infection, hospitalisation, disease severity and mortality stratified by smoking status. Study quality was assessed (i.e. ‘good', ‘fair' and ‘poor'). Findings: Version 7 (searches up to 25 August 2020) included 233 studies with 32 ‘good' and ‘fair' quality studies included in meta-analyses. Fifty-seven studies (24.5%) reported current, former and never smoking status. Recorded smoking prevalence among people with COVID-19 was generally lower than national prevalence. Current compared with never smokers were at reduced risk of SARS-CoV-2 infection (RR=0.74, 95% Credible Interval (CrI) = 0.58-0.93, τ = 0.41). Data for former smokers were inconclusive (RR=1.05, 95% CrI = 0.95-1.17, τ = 0.17) but favoured there being no important association (21% probability of RR ≥1.1). Former compared with never smokers were at somewhat increased risk of hospitalisation (RR=1.20, CrI = 1.03-1.44, τ = 0.17), greater disease severity (RR=1.52, CrI = 1.13-2.07, τ = 0.29), and mortality (RR=1.39, 95% CrI = 1.09-1.87, τ = 0.27). Data for current smokers were inconclusive (RR=1.06, CrI = 0.82-1.35, τ = 0.27;RR=1.25, CrI = 0.85-1.93, τ = 0.34;RR=1.22, 95% CrI = 0.78-1.94, τ = 0.49 respectively) but favoured there being no important associations with hospitalisation and mortality (35% and 70% probability of RR ≥1.1, respectively) and a small but important association with disease severity (79% probability of RR ≥1.1). Conclusions: Due to incomplete recording of smoking status, there is uncertainty about the associations of smoking with COVID-19 outcomes. Current smokers were at reduced risk of SARS-CoV-2 infection. Former smokers were at increased risk of hospitalisation, disease severity and mortality from COVID-19, while data for current smokers inconclusively favoured no large associations with these outcomes.
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Background: SARS-CoV-2 is the causative agent of COVID-19, an emergent zoonotic disease which has reached pandemic levels and is designated a public health emergency of international concern. It is plausible that former or current smoking status is associated with infection, hospitalisation and/or mortality from COVID-19. Objective: We aimed to estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19 disease. Methods: This is a living evidence review with frequent updates. We adopted recommended practice for rapid evidence reviews, which involved limiting the search to main databases and having one reviewer extract data and another verify. Published articles and pre-prints were identified via Ovid MEDLINE, medRxiv and expertise within the review team. We included observational or experimental studies with community-dwelling or hospitalised adults aged 16 years who had received a test for SARS-CoV-2 infection or a diagnosis of COVID-19, providing that data on smoking status were reported. Studies were judged as ‘good' quality if they: i) had low levels of missing data on smoking status (i.e.
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Background: SARS-CoV-2 is the causative agent of COVID-19, an emergent zoonotic disease which has reached pandemic levels and is designated a public health emergency of international concern. It is plausible that former or current smoking status is associated with infection, hospitalisation and/or mortality from COVID-19. Objective: We aimed to estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19 disease. Methods: This is a living evidence review with frequent updates. We adopted recommended practice for rapid evidence reviews, which involved limiting the search to main databases and having one reviewer extract data and another verify. Published articles and pre-prints were identified via Ovid MEDLINE, medRxiv and expertise within the review team. We included observational or experimental studies with community-dwelling or hospitalised adults aged 16 years who had received a test for SARS-CoV-2 infection or a diagnosis of COVID-19, providing that data on smoking status were reported. Studies were judged as ‘good' quality if they: i) had low levels of missing data on smoking status (i.e.
ABSTRACT
AIMS: To estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19 disease. DESIGN: Living rapid review of observational and experimental studies with random-effects hierarchical Bayesian meta-analyses. Published articles and pre-prints were identified via MEDLINE and medRxiv. SETTING: Community or hospital. No restrictions on location. PARTICIPANTS: Adults who received a SARS-CoV-2 test or a COVID-19 diagnosis. MEASUREMENTS: Outcomes were SARS-CoV-2 infection, hospitalisation, disease severity and mortality stratified by smoking status. Study quality was assessed (i.e. ‘good', ‘fair' and ‘poor'). FINDINGS: Version 9 (searches up to 27 October 2020) included 279 studies with 42 ‘good' and ‘fair' quality studies included in unadjusted meta-analyses. Seventy-nine studies (28%) reported current, former and never smoking status with the remainder using broader categories. Recorded smoking prevalence among people with COVID-19 was generally lower than national prevalence. Current compared with never smokers were at reduced risk of SARS-CoV-2 infection (RR = 0.69, 95% Credible Interval (CrI) = 0.57-0.83, τ = 0.38). Data for former smokers were inconclusive (RR = 1.02, 95% CrI = 0.93-1.12, τ = 0.18) but favoured there being no important association (5% probability of RR ≥1.1). Former compared with never smokers were at somewhat increased risk of hospitalisation (RR = 1.17, CrI = 1.04-1.36, τ = 0.17), greater disease severity (RR = 1.52, CrI = 1.12-2.06, τ = 0.29) and mortality (RR = 1.39, 95% CrI = 1.16-1.69, τ = 0.23). Data for current smokers on hospitalisation, disease severity and mortality were inconclusive (RR = 1.06, CrI = 0.89-1.27, τ = 0.23;RR = 1.26, CrI = 0.86-1.94, τ = 0.34;RR = 1.05, 95% CrI = 0.71-1.49, τ = 0.45, respectively) but favoured there being no important associations with hospitalisation and mortality (32% and 39% probability of RR ≥1.1, respectively) and a small but important association with disease severity (80% probability of RR ≥1.1). CONCLUSIONS: Compared with never smokers, current smokers appear to be at reduced risk of SARS-CoV-2 infection while former smokers appear to be at increased risk of hospitalisation, greater disease severity and mortality from COVID-19. However, it is uncertain whether these associations are causal. v7 of this living review article has been published in _Addiction _and is available here https://doi-org.libproxy.ucl.ac.uk/10.1111/add.15276
ABSTRACT
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant (B.1.1.529) rapidly replaced Delta (B.1.617.2) to become dominant in England. Our study assessed differences in transmission between Omicron and Delta using two independent data sources and methods. Omicron and Delta cases were identified through genomic sequencing, genotyping and S-gene target failure in England from 5-11 December 2021. Secondary attack rates for named contacts were calculated in household and non-household settings using contact tracing data, while household clustering was identified using national surveillance data. Logistic regression models were applied to control for factors associated with transmission for both methods. For contact tracing data, higher secondary attack rates for Omicron vs. Delta were identified in households (15.0% vs. 10.8%) and non-households (8.2% vs. 3.7%). For both variants, in household settings, onward transmission was reduced from cases and named contacts who had three doses of vaccine compared to two, but this effect was less pronounced for Omicron (adjusted risk ratio, aRR 0.78 and 0.88) than Delta (aRR 0.62 and 0.68). In non-household settings, a similar reduction was observed only in contacts who had three doses vs. two doses for both Delta (aRR 0.51) and Omicron (aRR 0.76). For national surveillance data, the risk of household clustering, was increased 3.5-fold for Omicron compared to Delta (aRR 3.54 (3.29-3.81)). Our study identified increased risk of onward transmission of Omicron, consistent with its successful global displacement of Delta. We identified a reduced effectiveness of vaccination in lowering risk of transmission, a likely contributor for the rapid propagation of Omicron.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , Cohort Studies , COVID-19/epidemiology , COVID-19/prevention & control , Vaccination , England/epidemiologyABSTRACT
When SARS-CoV-2 Omicron emerged in 2021, S gene target failure enabled differentiation between Omicron and the dominant Delta variant. In England, where S gene target surveillance (SGTS) was already established, this led to rapid identification (within ca 3 days of sample collection) of possible Omicron cases, alongside real-time surveillance and modelling of Omicron growth. SGTS was key to public health action (including case identification and incident management), and we share applied insights on how and when to use SGTS.
Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/epidemiology , Humans , Membrane Glycoproteins/genetics , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Viral Envelope Proteins/geneticsABSTRACT
BACKGROUND: A rapid increase in coronavirus disease 2019 (Covid-19) cases due to the omicron (B.1.1.529) variant of severe acute respiratory syndrome coronavirus 2 in highly vaccinated populations has aroused concerns about the effectiveness of current vaccines. METHODS: We used a test-negative case-control design to estimate vaccine effectiveness against symptomatic disease caused by the omicron and delta (B.1.617.2) variants in England. Vaccine effectiveness was calculated after primary immunization with two doses of BNT162b2 (Pfizer-BioNTech), ChAdOx1 nCoV-19 (AstraZeneca), or mRNA-1273 (Moderna) vaccine and after a booster dose of BNT162b2, ChAdOx1 nCoV-19, or mRNA-1273. RESULTS: Between November 27, 2021, and January 12, 2022, a total of 886,774 eligible persons infected with the omicron variant, 204,154 eligible persons infected with the delta variant, and 1,572,621 eligible test-negative controls were identified. At all time points investigated and for all combinations of primary course and booster vaccines, vaccine effectiveness against symptomatic disease was higher for the delta variant than for the omicron variant. No effect against the omicron variant was noted from 20 weeks after two ChAdOx1 nCoV-19 doses, whereas vaccine effectiveness after two BNT162b2 doses was 65.5% (95% confidence interval [CI], 63.9 to 67.0) at 2 to 4 weeks, dropping to 8.8% (95% CI, 7.0 to 10.5) at 25 or more weeks. Among ChAdOx1 nCoV-19 primary course recipients, vaccine effectiveness increased to 62.4% (95% CI, 61.8 to 63.0) at 2 to 4 weeks after a BNT162b2 booster before decreasing to 39.6% (95% CI, 38.0 to 41.1) at 10 or more weeks. Among BNT162b2 primary course recipients, vaccine effectiveness increased to 67.2% (95% CI, 66.5 to 67.8) at 2 to 4 weeks after a BNT162b2 booster before declining to 45.7% (95% CI, 44.7 to 46.7) at 10 or more weeks. Vaccine effectiveness after a ChAdOx1 nCoV-19 primary course increased to 70.1% (95% CI, 69.5 to 70.7) at 2 to 4 weeks after an mRNA-1273 booster and decreased to 60.9% (95% CI, 59.7 to 62.1) at 5 to 9 weeks. After a BNT162b2 primary course, the mRNA-1273 booster increased vaccine effectiveness to 73.9% (95% CI, 73.1 to 74.6) at 2 to 4 weeks; vaccine effectiveness fell to 64.4% (95% CI, 62.6 to 66.1) at 5 to 9 weeks. CONCLUSIONS: Primary immunization with two doses of ChAdOx1 nCoV-19 or BNT162b2 vaccine provided limited protection against symptomatic disease caused by the omicron variant. A BNT162b2 or mRNA-1273 booster after either the ChAdOx1 nCoV-19 or BNT162b2 primary course substantially increased protection, but that protection waned over time. (Funded by the U.K. Health Security Agency.).
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COVID-19 Vaccines , COVID-19 , Vaccine Efficacy , 2019-nCoV Vaccine mRNA-1273/therapeutic use , BNT162 Vaccine/therapeutic use , COVID-19/prevention & control , COVID-19 Vaccines/therapeutic use , Case-Control Studies , ChAdOx1 nCoV-19/therapeutic use , Humans , Immunization, Secondary/adverse effects , SARS-CoV-2/geneticsABSTRACT
AIMS: To estimate the association of smoking status with rates of (i) infection, (ii) hospitalization, (iii) disease severity and (iv) mortality from SARS-CoV-2/COVID-19 disease. DESIGN: Living rapid review of observational and experimental studies with random-effects hierarchical Bayesian meta-analyses. Published articles and pre-prints were identified via MEDLINE and medRxiv. SETTING: Community or hospital, no restrictions on location. PARTICIPANTS: Adults who received a SARS-CoV-2 test or a COVID-19 diagnosis. MEASUREMENTS: Outcomes were SARS-CoV-2 infection, hospitalization, disease severity and mortality stratified by smoking status. Study quality was assessed (i.e. 'good', 'fair' and 'poor'). FINDINGS: Version 7 (searches up to 25 August 2020) included 233 studies with 32 'good' and 'fair' quality studies included in meta-analyses. Fifty-seven studies (24.5%) reported current, former and never smoking status. Recorded smoking prevalence among people with COVID-19 was generally lower than national prevalence. Current compared with never smokers were at reduced risk of SARS-CoV-2 infection [relative risk (RR) = 0.74, 95% credible interval (CrI) = 0.58-0.93, τ = 0.41]. Data for former smokers were inconclusive (RR = 1.05, 95% CrI = 0.95-1.17, τ = 0.17), but favoured there being no important association (21% probability of RR ≥ 1.1). Former compared with never smokers were at somewhat increased risk of hospitalization (RR = 1.20, CrI = 1.03-1.44, τ = 0.17), greater disease severity (RR = 1.52, CrI = 1.13-2.07, τ = 0.29) and mortality (RR = 1.39, 95% CrI = 1.09-1.87, τ = 0.27). Data for current smokers were inconclusive (RR = 1.06, CrI = 0.82-1.35, τ = 0.27; RR = 1.25, CrI = 0.85-1.93, τ = 0.34; RR = 1.22, 95% CrI = 0.78-1.94, τ = 0.49, respectively), but favoured there being no important associations with hospitalization and mortality (35% and 70% probability of RR ≥ 1.1, respectively) and a small but important association with disease severity (79% probability of RR ≥ 1.1). CONCLUSIONS: Compared with never smokers, current smokers appear to be at reduced risk of SARS-CoV-2 infection, while former smokers appear to be at increased risk of hospitalization, increased disease severity and mortality from COVID-19. However, it is uncertain whether these associations are causal.
Subject(s)
COVID-19/epidemiology , COVID-19/mortality , SARS-CoV-2 , Smoking/epidemiology , Smoking/mortality , Bayes Theorem , Hospitalization , Humans , Mortality , Prevalence , Risk , Severity of Illness IndexABSTRACT
Aims To estimate the association of smoking status with rates of (i) infection, (ii) hospitalization, (iii) disease severity and (iv) mortality from SARS-CoV-2/COVID-19 disease. Design Living rapid review of observational and experimental studies with random-effects hierarchical Bayesian meta-analyses. Published articles and pre-prints were identified via MEDLINE and medRxiv. Setting Community or hospital, no restrictions on location. Participants Adults who received a SARS-CoV-2 test or a COVID-19 diagnosis. Measurements Outcomes were SARS-CoV-2 infection, hospitalization, disease severity and mortality stratified by smoking status. Study quality was assessed (i.e. 'good', 'fair' and 'poor'). Findings Version 7 (searches up to 25 August 2020) included 233 studies with 32 'good' and 'fair' quality studies included in meta-analyses. Fifty-seven studies (24.5%) reported current, former and never smoking status. Recorded smoking prevalence among people with COVID-19 was generally lower than national prevalence. Current compared with never smokers were at reduced risk of SARS-CoV-2 infection [relative risk (RR) = 0.74, 95% credible interval (CrI) = 0.58-0.93, tau = 0.41]. Data for former smokers were inconclusive (RR = 1.05, 95% CrI = 0.95-1.17, tau = 0.17), but favoured there being no important association (21% probability of RR >= 1.1). Former compared with never smokers were at somewhat increased risk of hospitalization (RR = 1.20, CrI = 1.03-1.44, tau = 0.17), greater disease severity (RR = 1.52, CrI = 1.13-2.07, tau = 0.29) and mortality (RR = 1.39, 95% CrI = 1.09-1.87, tau = 0.27). Data for current smokers were inconclusive (RR = 1.06, CrI = 0.82-1.35, tau = 0.27;RR = 1.25, CrI = 0.85-1.93, tau = 0.34;RR = 1.22, 95% CrI = 0.78-1.94, tau = 0.49, respectively), but favoured there being no important associations with hospitalization and mortality (35% and 70% probability of RR >= 1.1, respectively) and a small but important association with disease severity (79% probability of RR >= 1.1). Conclusions Compared with never smokers, current smokers appear to be at reduced risk of SARS-CoV-2 infection, while former smokers appear to be at increased risk of hospitalization, increased disease severity and mortality from COVID-19. However, it is uncertain whether these associations are causal. (PsycInfo Database Record (c) 2021 APA, all rights reserved)