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Cited by 794SARS-CoV-2 and COVID-19 ResearchVaccine Coverage and HesitancyCOVID-19 epidemiological studies

COVID-19 vaccine coverage in health-care workers in England and effectiveness of BNT162b2 mRNA vaccine against infection (SIREN): a prospective, multicentre, cohort study

Open access
Hall, Victoria Jane, Foulkes, Sarah, Saei, Ayoub, Andrews, Nick, Oguti, Blanche, Charlett, Andre, Wellington, Edgar, Stowe, Julia +346 more·2021·The Lancet
DOI 10.1016/s0140-6736(21)00790-xPMC PMC8064668
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Abstract

Background BNT162b2 mRNA and ChAdOx1 nCOV-19 adenoviral vector vaccines have been rapidly rolled out in the UK from December, 2020. We aimed to determine the factors associated with vaccine coverage for both vaccines and documented the vaccine effectiveness of the BNT162b2 mRNA vaccine in a cohort of health-care workers undergoing regular asymptomatic testing. Methods The SIREN study is a prospective cohort study among staff (aged ≥18 years) working in publicly-funded hospitals in the UK. Participants were assigned into either the positive cohort (antibody positive or history of infection [indicated by previous positivity of antibody or PCR tests]) or the negative cohort (antibody negative with no previous positive test) at the beginning of the follow-up period. Baseline risk factors were collected at enrolment, symptom status was collected every 2 weeks, and vaccination status was collected through linkage to the National Immunisations Management System and questionnaires. Participants had fortnightly asymptomatic SARS-CoV-2 PCR testing and monthly antibody testing, and all tests (including symptomatic testing) outside SIREN were captured. Data cutoff for this analysis was Feb 5, 2021. The follow-up period was Dec 7, 2020, to Feb 5, 2021. The primary outcomes were vaccinated participants (binary ever vacinated variable; indicated by at least one vaccine dose recorded by at least one of the two vaccination data sources) for the vaccine coverage analysis and SARS-CoV-2 infection confirmed by a PCR test for the vaccine effectiveness analysis. We did a mixed-effect logistic regression analysis to identify factors associated with vaccine coverage. We used a piecewise exponential hazard mixed-effects model (shared frailty-type model) using a Poisson distribution to calculate hazard ratios to compare time-to-infection in unvaccinated and vaccinated participants and estimate the impact of the BNT162b2 vaccine on all PCR-positive infections (asymptomatic and symptomatic). This study is registered with ISRCTN, number ISRCTN11041050, and is ongoing. Findings 23 324 participants from 104 sites (all in England) met the inclusion criteria for this analysis and were enrolled. Included participants had a median age of 46·1 years (IQR 36·0-54·1) and 19 692 (84%) were female; 8203 (35%) were assigned to the positive cohort at the start of the analysis period, and 15 121 (65%) assigned to the negative cohort. Total follow-up time was 2 calendar months and 1 106 905 person-days (396 318 vaccinated and 710 587 unvaccinated). Vaccine coverage was 89% on Feb 5, 2021, 94% of whom had BNT162b2 vaccine. Significantly lower coverage was associated with previous infection, gender, age, ethnicity, job role, and Index of Multiple Deprivation score. During follow-up, there were 977 new infections in the unvaccinated cohort, an incidence density of 14 infections per 10 000 person-days; the vaccinated cohort had 71 new infections 21 days or more after their first dose (incidence density of eight infections per 10 000 person-days) and nine infections 7 days after the second dose (incidence density four infections per 10 000 person-days). In the unvaccinated cohort, 543 (56%) participants had typical COVID-19 symptoms and 140 (14%) were asymptomatic on or 14 days before their PCR positive test date, compared with 29 (36%) with typical COVID-19 symptoms and 15 (19%) asymptomatic in the vaccinated cohort. A single dose of BNT162b2 vaccine showed vaccine effectiveness of 70% (95% CI 55-85) 21 days after first dose and 85% (74-96) 7 days after two doses in the study population. Interpretation Our findings show that the BNT162b2 vaccine can prevent both symptomatic and asymptomatic infection in working-age adults. This cohort was vaccinated when the dominant variant in circulation was B1.1.7 and shows effectiveness against this variant. Funding Public Health England, UK Department of Health and Social Care, and the National Institute for Health Research.

Verified 2026-10-06 · 1 reference not checked yet

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Crossref · 10.1016/s0140-6736(21)00790-x

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Claims the paper makes

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  • Findingown data

    Among new infections, typical COVID-19 symptoms were present in 543 (56%) unvaccinated participants and 29 (36%) vaccinated participants.

    “In the unvaccinated cohort, 543 (56%) participants had typical COVID-19 symptoms and 140 (14%) were asymptomatic on or 14 days before their PCR positive test date, compared with 29 (36%) with typical COVID-19 symptoms and 15 (19%) asymptomatic in the vaccinated cohort.”
    Quote in the paperNot a substantial claim
  • Findingown data

    The estimated effectiveness of BNT162b2 was 85% (95% CI 74-96) at 7 days after the second dose in the study population.

    “and 85% (74–96) 7 days after two doses in the study population.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: An immunological response to the vaccine dose is provoked by 21 days after the first dose and 7 days after the second dose.
  • Findingown data

    Female gender was associated with lower vaccine coverage compared with male (adjusted OR 0.72, 95% CI 0.63-0.82).

    “| Female | 2346 (11·9%) | 17 346 (88·1%) | 0·75 (0·67–0·85) | .. | 0·72 (0·63–0·82) | .. |”
    Quote in the paperNot a substantial claim
  • Findingown data

    Black ethnicity was associated with lower vaccine coverage compared with White ethnicity (adjusted OR 0.26, 95% CI 0.21-0.32).

    “| Black | 162 (34·9%) | 302 (65·1%) | 0·22 (0·18–0·26) | .. | 0·26 (0·21–0·32) | .. |”
    Quote in the paperNot a substantial claim
  • Findingown data

    Job role was associated with vaccine coverage.

    “Significantly lower coverage was associated with previous infection, gender, age, ethnicity, job role, and Index of Multiple Deprivation score.”
    Quote in the paperNot a substantial claim
  • May combine two claims. 18
  • Classified as probably not a substantial claim. 11

  • May combine two claims.

    Findingown data

    Greater deprivation was associated with lower vaccine coverage; the most deprived IMD quintile had adjusted OR 0.75 (95% CI 0.65-0.87) compared with the least deprived quintile.

    “| 1 (most deprived) | 436 (16·6%) | 2198 (83·4%) | 0·50 (0·44–0·57) | .. | 0·75 (0·65–0·87) | .. |”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Older age was associated with higher vaccine coverage; for example, age 45-54 years had adjusted OR 2.22 (95% CI 1.80-2.73) compared with age <25 years.

    “| 45–54 | 600 (8·4%) | 6566 (91·6%) | 2·09 (1·71–2·56) | .. | 2·22 (1·80–2·73) | .. |”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In vaccinated participants, nine new infections occurred 7 days after the second dose, with an incidence density of four per 10 000 person-days.

    “and nine infections 7 days after the second dose (incidence density four infections per 10 000 person-days)”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Among new infections, asymptomatic status was present in 140 (14%) unvaccinated participants and 15 (19%) vaccinated participants.

    “In the unvaccinated cohort, 543 (56%) participants had typical COVID-19 symptoms and 140 (14%) were asymptomatic on or 14 days before their PCR positive test date, compared with 29 (36%) with typical COVID-19 symptoms and 15 (19%) asymptomatic in the vaccinated cohort.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Among vaccinated participants, 71 new infections occurred at least 21 days after the first dose, with an incidence density of eight per 10 000 person-days.

    “the vaccinated cohort had 71 new infections 21 days or more after their first dose (incidence density of eight infections per 10 000 person-days)”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In the unvaccinated group, 977 new infections occurred during follow-up, giving an incidence density of 14 per 10 000 person-days.

    “During follow-up, there were 977 new infections in the unvaccinated cohort, an incidence density of 14 infections per 10 000 person-days”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The median interval between first and second vaccine doses was 23 days (IQR 21-26).

    “The median length of time between first dose and second dose was 23 days (IQR 21–26; range 19–28).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Among vaccinated participants, 19,384 (94%) received the BNT162b2 vaccine and 1,252 (6%) received the ChAdOx1 vaccine as their first dose.

    “19 384 (94%) received the BNT162b2 vaccine and 1252 (6%) received the ChAdOx1 vaccine”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Protection from infection rose substantially from day 10 and reached a plateau after 21 days.

    “with substantial protection from infection increasing from day 10 onwards and plateauing after 21 days”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Vaccinated participants had 71 new infections 21 days after the first dose, an incidence density of 8 per 10,000 person-days.

    “In the vaccinated group, 21 days after the first dose, there were 71 new infections (incidence density of eight per 10 000 person-days of follow-up)”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Vaccinated participants had 9 new infections 7 days after the second dose, an incidence density of 4 per 10,000 person-days.

    “and nine new infections 7 days after the second dose (incidence density of four per 10 000 person-days of follow-up)”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Participants from Black, Asian or minority ethnic groups had lower odds of vaccination, with Black participants having the lowest odds (aOR 0.26, 95% CI 0.21-0.32).

    “Participants were less likely to have been vaccinated if they had a previous infection (adjusted odds ratio [aOR] 0·59, 95% CI 0·54–0·64), were female (0·72, 0·63–0·82), were aged under 35 (0·78, 0·64–0·96), were from Black, Asian or minority ethnic groups, especially if they were Black (0·26, 0·21–0·32)”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The study followed STROBE reporting guidelines.

    “The study follows the Strengthening the Reporting of Observational studies in Epidemiology guidelines.15”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15] von Elm E Altman DG Egger M Pocock SJ Gøtzsche PC Vandenbroucke JP The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies Lancet 370 2007 1453 1457 18064739 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Potential confounders such as hospital site and participant demographics were recorded so that adjusted analyses could be performed.

    “We collected data on potential confounders, including site and participant demographics, to enable adjusted analysis.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    To prevent exposure misclassification, follow-up was stopped at the date of an unreliable second dose.

    “To avoid misclassification of exposure, if a participant had an unreliable date of a second dose (eg, a second dose administered before a first dose or administered less than 19 days after the first dose) their follow-up time was censored at the date of the suspect second dose.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    The end of follow-up was defined to avoid immortal time bias.

    “We defined the end of follow-up in those who were not positive cases as the date of a negative test or Feb 5, 2021, if the test was after this date, to avoid immortal time bias.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Before the vaccine rollout, the precision of effectiveness estimates was assessed assuming 40 000 participants, 65% seronegative at baseline, 75% average coverage, and 0.5-5% incidence during follow-up.

    “Before vaccine introduction, we calculated the precision of effectiveness estimates on an estimated cohort size of 40 000 participants, with 65% seronegativity at baseline, coverage averaging 75% in the follow-up period, and incidence in the follow-up period ranging from 0·5% to 5%.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    The analysis included only one vaccine manufacturer, chosen because enough follow-up time was available.

    “We restricted our analysis to one manufacturer only, where sufficient follow-up time had accrued.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The study was registered with ISRCTN11041050.

    “This study is registered with ISRCTN, number ISRCTN11041050.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Most data on vaccinated individuals in the UK are from people aged >75 years, in whom vaccine effectiveness can be lower due to immunosenescence.

    “Notably, to date, most data on vaccinated individuals in the UK are from people aged >75 years old, in whom vaccine effectiveness can be lower due to immunosenesence.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [26] Aiello A Farzaneh F Candore G Immunosenescence and its hallmarks: how to oppose aging strategically? A review of potential options for therapeutic intervention Front Immunol 10 2019 2247 PMC6773825 31608061

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The final model's mean χ2 was 1.04, indicating no evidence against the model.

    “The final model resulted in a mean χ2 estimate of 1·04. Since the mean of χ2 variable is its degree of freedom, comparing the mean χ2 with its mean value 1 provides a quick check model. The estimated χ2 value of 1·04 is not too far from 1, which implies that there is no evidence against the final model.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: The proportional hazards assumption holds in the piecewise exponential hazard model.

  • May combine two claims.

    Study design and conductown data

    The testing frequency in the vaccinated population was higher than in the unvaccinated population (10.4 vs 14.3 days per test), which would bias vaccine effectiveness results towards the null.

    “The testing frequency in our vaccinated population was slightly higher than in the unvaccinated population (10·4 days per test vs 14·3 days per test), making us more likely to pick up infections among the vaccinated, and, therefore, biasing our vaccine effectiveness results towards the null hypothesis.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    The SIREN cohort's findings are more relevant for the general adult population because it is composed of working-age adults, though healthy worker effect bias might underestimate disease impact.

    “Given the SIREN cohort is composed of working-age adults, the findings are more relevant for the general adult population, although the healthy worker effect bias might underestimate the disease impact compared with the general population.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [27] Shah D Healthy worker effect phenomenon Indian J Occup Environ Med 13 2009 77 79 20386623 PMC2847330

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    The study was unable to investigate the effectiveness of the ChAdOx1 nCoV-19 vaccine because few participants received it and follow-up was short.

    “With fewer of the cohort vaccinated with the ChAdOx1 nCoV-19 vaccine, and the later roll-out resulting in less follow-up time accrued, we are unable to investigate the effectiveness of the ChAdOx1 nCoV-19 vaccine within this analysis.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    A substudy of the Oxford-AstraZeneca COVID-19 vaccine reported reduced viral load and PCR positivity in vaccinated participants, suggesting transmission might be reduced.

    “A substudy of the Oxford–AstraZeneca COVID-19 vaccine did weekly swabbing and reported reduced viral load and PCR positivity in vaccinated participants; a signal that transmission might be reduced by this vaccine.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [28] Emary KRW Golubchik T Aley PK Efficacy of ChAdOx1 nCoV-19 (AZD1222) Vaccine Against SARS-CoV-2 VOC 202012/01 (B.1.1.7) Lancet 397 2021 1351 1362 33798499 PMC8009612

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The B.1.1.7 variant was dominant in England during the study period, accounting for ≥50% of positive tests in certain regions from December 2020 and in all regions by early January 2021.

    “Given the dominance of the B.1.1.7 variant in England during the study period, which accounted for 50% or more positive tests in Pillar 2 laboratories since the beginning of December, 2020, in the South East, London, and East of England, and in all regions by early January 2021”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [16] Public Health England Investigation of SARS-CoV-2 variants of concern in England. Technical briefing 6 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/961299/Variants_of_Concern_VOC_Technical_Briefing_6_England-1.pdf Feb 13, 2021

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    Infections detected shortly after vaccination might have been acquired before vaccination, which would bias vaccine effectiveness towards the null.

    “it is also possible that infections detected at a short interval after vaccination were acquired before vaccination, and, therefore, were misclassified as events within vaccinated follow-up, biasing vaccine effectiveness to the null hypothesis.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Symptom status ascertained by self-completed questionnaires at 14-day intervals could introduce recall bias.

    “given our symptom status is ascertained by self-completed questionnaires sent at 14-day intervals, there is the possibility of recall bias”
    Quote in the paperNot a substantial claim
28 of 28

  • The authors state this as an assumption.

    The proportional hazards assumption holds in the piecewise exponential hazard model.

    “The proportional hazards in this model is an assumption.”

  • The authors state this as an assumption.

    The hospital trust random effect is normally distributed.

    “The hospital trust random effect was assumed to be normal, and this implies that frailty (exp(hospital trusts)) distribution was log-normal.”

  • The paper relies on this without support.

    The dominant SARS-CoV-2 variant in circulation during the study period was B1.1.7.

    “This cohort was vaccinated when the dominant variant in circulation was B1.1.7 and shows effectiveness against this variant.”

  • The paper relies on this without support.

    An immunological response to the vaccine dose is provoked by 21 days after the first dose and 7 days after the second dose.

    “We calculated hazard ratios from 21 days after first dose and 7 days after second dose using a weighted average method, the point at which an immunological response to the vaccine dose should have been provoked.”

  • The paper relies on this without support.

    At the time of the study, there was a scarcity of published research on whether vaccination reduces asymptomatic infection or transmission worldwide.

    “To date, little has been published on the effect of vaccination on reducing asymptomatic infection or transmission globally.”
5 of 5

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • ChAdOx1 maintains efficacy against B.1.1.7 but has a major loss in efficacy against mild COVID-19 with the B.1.351 variant.

    “ChAdOx1 maintains efficacy against B.1.1.724,27 but has a major loss in efficacy against mild COVID-19 with the B.1.351 variant.26”

    From Impact of SARS-CoV-2 variants on the total CD4+ and CD8+ T cell reactivity in infected or vaccinated individuals (2021) · cites this paper as [27]

  • There may be differences among the populations that received each vaccine, such as younger health care workers being more likely to receive BNT162b2 and persons in clinical risk groups more likely to receive ChAdOx1 nCoV-19.

    “There may also be differences among the populations that received each vaccine — for example, in younger age groups, health care workers are more likely to have received the BNT162b2 vaccine, whereas persons in clinical risk groups are more likely to have received the ChAdOx1 nCoV-19 vaccine.11”

    From Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant (2021) · cites this paper as [11]

  • Covid-19 vaccines are highly effective against symptomatic disease and, more so, against severe disease and fatal outcomes caused by the original strain of SARS-CoV-2 as well as the alpha variant.

    “Coronavirus disease 2019 (Covid-19) vaccines are highly effective against symptomatic disease and, more so, against severe disease and fatal outcomes caused by the original strain of SARS-CoV-2 as well as the alpha (B.1.1.7) variant that predominated in early 2021.”

    From Effectiveness of COVID-19 vaccines against the Omicron (B.1.1.529) variant of concern (2021) · cites this paper as [12]

Cites

Flagged first, then by citations

2 of the 27 references couldn’t be matched to a known paper.

Research works printed but not linked: 1

  1. MacKenna, 2021, Trends, regional variation, and clinical characteristics of COVID-19 vaccine recipients: a retrospective cohort study in 23·4 million patients using OpenSAFELY, medRxiv

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Authors
Hall, V. J., Foulkes, S., Saei, A., Andrews, N., Oguti, B., Charlett, A., Wellington, E., Stowe, J., Gillson, N., Atti, A., Islam, J., Karagiannis, I., Munro, K., Khawam, J., Chand, M. A., Brown, C. S., Ramsay, M., Lopez-Bernal, J., Hopkins, S., Andrews, N., Atti, A., Aziz, H., Brooks, T., Brown, C., Camero, D., Carr, C., Chand, M., Charlett, A., Crawford, H., Cole, M., Conneely, J., D'Arcangelo, S., Ellis, J., Evans, S., Foulkes, S., Gillson, N., Gopal, R., Hall, L., Hall, V., Harrington, P., Hopkins, S., Hewson, J., Hoschler, K., Ironmonger, D., Islam, J., Kall, M., Karagiannis, I., Kay, O., Khawam, J., King, E., Kirwan, P., Kyffin, R., Lackenby, A., Lattimore, M., Linley, E., Lopez-Bernal, J., Mabey, L., McGregor, R., Miah, S., Monk, E., Munro, K., Naheed, Z., Nissr, A., O'Connell, A., Oguti, B., Okafor, H., Organ, S., Osbourne, J., Otter, A., Patel, M., Platt, S., Pople, D., Potts, K., Ramsay, M., Robotham, J., Rokadiya, S., Rowe, C., Saei, A., Sebbage, G., Semper, A., Shrotri, M., Simmons, R., Soriano, A., Staves, P., Taylor, S., Taylor, A., Tengbe, A., Tonge, S., Vusirikala, A., Wallace, S., Wellington, E., Zambon, M., Corrigan, D., Sartaj, M., Cromey, L., Campbell, S., Braithwaite, K., Price, L., Haahr, L., Stewart, S., Lacey, E., Partridge, L., Stevens, G., Ellis, Y., Hodgson, H., Norman, C., Lacey, E., Larru, B., Mcwilliam, S., Roynon, A., Northfield, J., Winchester, S., Cieciwa, P., Pai, A., Bakker, P., Loughrey, C., Watt, A., Adair, F., Hawkins, A., Grant, A., Temple-Purcell, R., Howard, J., Slawson, N., Subudhi, C., Davies, S., Bexley, A., Penn, R., Wong, N., Boyd, G., Rajgopal, A., Arenas-Pinto, A., Matthews, R., Whileman, A., Laugharne, R., Ledger, J., Barnes, Jones, C., Osuji, N., Chitalia, N., Bailey, T., Akhtar, S., Harrison, G., Horne, S., Walker, N., Agwuh, K., Maxwell, V, Graves, J., Williams, S., O'Kelly, A., Ridley, P., Cowley, A., Johnstone, H., Swift, P., Democratis, J., Meda, M., Brake, S., Gunn, J., Selassi, A., Hams, S., Irvine, V, Chandrasekaran, B., Forsyth, C., Radmore, J., Thomas, C., Brown, K., Roberts, S., Burns, P., Gajee, K., Lewis, T., Byrne, T., Sanderson, F., Knight, S., Macnaughton, E., Burton, B., Smith, H., Chaudhuri, R., Aeron-Thomas, J., Hollinshead, K., Shorten, R., Swan, A., Shorten, R., Favager, C., Murira, J., Baillon, S., Hamer, S., Shah, A., Russell, J., Brennan, D., Dave, A., Chawla, A., Westwell, F., Adeboyeku, D., Papineni, P., Pegg, C., Williams, M., Ahmad, S., Horsley, A., Gabriel, C., Pagget, K., Cieciwa, P., Maloney, G., Ashcroft, J., Del Rosario, I., Crosby-Nwaobi, R., Flanagan, D., Dhasmana, D., Fowler, S., Cameron, E., Prentice, L., Sinclair, C., Irvine, V, Bateman, V, McLelland-Brooks, K., Ho, A., Murphy, M., Cochrane, A., Gibson, A., Patel, M., Black, K., Tempeton, K., Donaldson, S., Coke, L., Elumogo, N., Elliott, J., Padgett, D., Cross, A., Mirfenderesky, M., Joyce, S., Sinanovic, I., Howard, M., Lewis, T., Cowling, P., Brazil, M., Hanna, E., Abdelrazik, A., Brand, S., Sheridan, E., Wadams, B., Lloyd, A., Mouland, J., Giles, J., Pottinger, G., Coles, H., Joseph, M., Lee, M., Orr, S., Chenoweth, H., Browne, D., Auckland, C., Lear, R., Mahungu, T., Rodger, A., Warren, S., Brooking, D., Pai, S., Druyeh, R., Smith, E., Stone, S., Meisner, S., Delgado, D., Underhill, E., Keen, L., Aga, M., Domingos, P., Gormley, S., Kerrison, C., Birch, S., DeSilva, T., Allsop, L., Ambalkar, S., Beekes, M., Jose, S., Tomlinson, J., Painter, S., Price, C., Pepperell, J., James, K., Trinick, T., Moore, L., Day, J., Boulos, A., Knox, I., Defever, E., McCracken, D., Brown, K., Gray, K., Houston, A., Planche, T., Pritchard Jones, R., Wycherley, D., Bennett, S., Marrs, J., Nimako, K., Stewart, B., Bain, S., Kalakonda, N., Khanduri, S., Ashby, A., Holden, M., Mahabir, N., Harwood, J., Payne, B., Court, K., White, N., Longfellow, R., Hughes, L., Green, M., Halkes, M., Mercer, P., Roebuck, A., Wilson-Davies, E., Gallego, L., Lazarus, R., Aldridge, N., Berry, L., Game, F., Reynolds, T., Holmes, C., Wiselka, M., Higham, A., Booth, M., Duff, C., Alderton, J., Hilton, D., Powell, J., Jackson, A., Plant, A., Ahmed, N., Chin, T., Qazzafi, M., Moody, A., Tilley, R., Donaghy, T., O'Kane, M., Shipman, K., Sierra, R., Parmar, C., Mills, G., Harvey, D., Huang, Y., Birch, J., Robinson, L., Board, S., Broadley, A., Laven, C., Todd, N., Eyre, D., Jeffery, K., Dunachie, S., Duncan, C., Klenerman, P., Turtle, L., Baxendale, H., & Heeney, J.
Affiliations
  • Public Health England (GB)
  • St Thomas' Hospital (GB)
  • Guy's Hospital (GB)
Corresponding author
  • Aziz, H
  • Carr, C
  • Crawford, H
  • Okafor, H
  • Potts, K
  • Rowe, C
  • Braithwaite, K
  • Hodgson, H
  • Norman, C
  • Loughrey, C
  • Adair, F
  • Subudhi, C
  • Jones, C
  • Agwuh, K
  • Johnstone, H
  • Forsyth, C
  • Thomas, C
  • Gajee, K
  • Sanderson, F
  • Smith, H
  • Hollinshead, K
  • Favager, C
  • Westwell, F
  • Pegg, C
  • Gabriel, C
  • Pagget, K
  • Sinclair, C
  • McLelland-Brooks, K
  • Ho, A
  • Black, K
  • Tempeton, K
  • Coles, H
  • Chenoweth, H
  • Auckland, C
  • Kerrison, C
  • Price, C
  • James, K
  • Gray, K
  • Nimako, K
  • Court, K
  • Game, F
  • Holmes, C
  • Duff, C
  • Shipman, K
  • Parmar, C
  • Laven, C
  • Jeffery, K
  • Duncan, C
  • Baxendale, H
ORCID
Venue
The Lancet
Publisher
Elsevier BV
Published
2021-05
Volume
397
Issue
10286
Pages
1725-1735
ISSN
  • 0099-5355 (ISSN-L)
  • 0140-6736
DOI
10.1016/s0140-6736(21)00790-x
PMC
PMC8064668
OpenAlex
W3159191704
Cited by
767
References
27
Citations by year
2026: 18 · 2025: 34 · 2024: 55 · 2023: 109 · 2022: 270 · 2021: 278 · 2020: 3
FWCI
56.38
Type
journal article
Language
en
Open access
Licence
Locations
  • The Lancet (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • ResearchOnline (Glasgow Caledonian University) (submittedVersion, cc-by-nc-nd)
  • UCL Discovery (University College London) (submittedVersion)
Funders
  • United Kingdom Department of Health and Social Care
  • Public Health England
  • National Institute for Health Research
Topics
  • Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
  • Social Sciences › Health › Vaccine Coverage and Hesitancy
  • Physical Sciences › Mathematics › Modeling and Simulation › COVID-19 epidemiological studies
Keywords
COVID-19 vaccination, BNT162b2 mRNA vaccine, ChAdOx1 nCoV-19 vaccine, vaccination coverage, healthcare workers, hospital staff, vaccine effectiveness, COVID-19 pandemic, asymptomatic testing, time to infection, shared frailty model, England, SIREN study, nosocomial infections
MeSH terms
COVID-19 Vaccines, BNT162 Vaccine, England, Health Personnel, Humans, Occupational Diseases, Prospective Studies, RNA, Messenger, Cohort Studies, Occupational Exposure, Treatment Outcome

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-06.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-06.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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