22 research outputs found
Beyond Provenance: New Approaches to Interpreting the Chemistry of Archaeological Copper Alloys
For the last 180 years, scientists have been attempting to determine the ‘provenance’ (geological source) of the copper used in Bronze Age artefacts. However, despite advances in analytical technologies, the theoretical approach has remained virtually unchanged over this period, with the interpretative methodology only changing to accommodate the increasing capacity of computers. This book represents a concerted effort to think about the composition of Bronze Age metal as the product of human intentionality as well as of geology. It considers the trace element composition of the metal, the alloying elements, and the lead isotopic composition, showing how a combination of these aspects, along with archaeological context and typology, can reveal much more about the life history of such artefacts, expanding considerably upon the rather limited ambition of knowing where the ore was extracted. Beyond Provenance serves as a ‘how-to handbook’ for those wishing to look for evidence of human intentionality in the chemical patterning observed in bronzes
SARS-CoV-2 antibody trajectories after a single COVID-19 vaccination with and without prior infection
Given high SARS-CoV-2 incidence, coupled with slow and inequitable vaccine roll-out in many settings, there is a need for evidence to underpin optimum vaccine deployment, aiming to maximise global population immunity. We evaluate whether a single vaccination in individuals who have already been infected with SARS-CoV-2 generates similar initial and subsequent antibody responses to two vaccinations in those without prior infection. We compared anti-spike IgG antibody responses after a single vaccination with ChAdOx1, BNT162b2, or mRNA-1273 SARS-CoV-2 vaccines in the COVID-19 Infection Survey in the UK general population. In 100,849 adults median (50 (IQR: 37–63) years) receiving at least one vaccination, 13,404 (13.3%) had serological/PCR evidence of prior infection. Prior infection significantly boosted antibody responses, producing higher peak levels and/or longer half-lives after one dose of all three vaccines than those without prior infection receiving one or two vaccinations. In those with prior infection, the median time above the positivity threshold was >1 year after the first vaccination. Single-dose vaccination targeted to those previously infected may provide at least as good protection to two-dose vaccination among those without previous infection
Antibodies to SARS-CoV-2 are associated with protection against reinfection
Background:Â The relationship between the presence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the risk of subsequent reinfection remains unclear.
Methods:Â We investigated the incidence of SARS-CoV-2 infection confirmed by polymerase chain reaction (PCR) in seropositive and seronegative health care workers attending testing of asymptomatic and symptomatic staff at Oxford University Hospitals in the United Kingdom. Baseline antibody status was determined by anti-spike (primary analysis) and anti-nucleocapsid IgG assays, and staff members were followed for up to 31 weeks. We estimated the relative incidence of PCR-positive test results and new symptomatic infection according to antibody status, adjusting for age, participant-reported gender, and changes in incidence over time.
Results: A total of 12,541 health care workers participated and had anti-spike IgG measured; 11,364 were followed up after negative antibody results and 1265 after positive results, including 88 in whom seroconversion occurred during follow-up. A total of 223 anti-spike–seronegative health care workers had a positive PCR test (1.09 per 10,000 days at risk), 100 during screening while they were asymptomatic and 123 while symptomatic, whereas 2 anti-spike–seropositive health care workers had a positive PCR test (0.13 per 10,000 days at risk), and both workers were asymptomatic when tested (adjusted incidence rate ratio, 0.11; 95% confidence interval, 0.03 to 0.44; P=0.002). There were no symptomatic infections in workers with anti-spike antibodies. Rate ratios were similar when the anti-nucleocapsid IgG assay was used alone or in combination with the anti-spike IgG assay to determine baseline status.
Conclusions:Â The presence of anti-spike or anti-nucleocapsid IgG antibodies was associated with a substantially reduced risk of SARS-CoV-2 reinfection in the ensuing 6 months. (Funded by the U.K. Government Department of Health and Social Care and others.
Fatal COVID-19 outcomes are associated with an antibody response targeting epitopes shared with endemic coronaviruses
The role of immune responses to previously seen endemic coronavirus epitopes in severe acute respiratory coronavirus 2 (SARS-CoV-2) infection and disease progression has not yet been determined. Here, we show that a key characteristic of fatal coronavirus disease (COVID-19) outcomes is that the immune response to the SARS-CoV-2 spike protein is enriched for antibodies directed against epitopes shared with endemic beta-coronaviruses, and has a lower proportion of antibodies targeting the more protective variable regions of the spike. The magnitude of antibody responses to the SARS-CoV-2 full-length spike protein, its domains and subunits, and the SARS-CoV-2 nucleocapsid also correlated strongly with responses to the endemic beta-coronavirus spike proteins in individuals admitted to intensive care units (ICU) with fatal COVID-19 outcomes, but not in individuals with non-fatal outcomes. This correlation was found to be due to the antibody response directed at the S2 subunit of the SARS-CoV-2 spike protein, which has the highest degree of conservation between the beta-coronavirus spike proteins. Intriguingly, antibody responses to the less cross-reactive SARS-CoV-2 nucleocapsid were not significantly different in individuals who were admitted to ICU with fatal and non-fatal outcomes, suggesting an antibody profile in individuals with fatal outcomes consistent with an original antigenic sin type-response
Risk of SARS-CoV-2 reinfection during multiple Omicron variant waves in the UK general population
SARS-CoV-2 reinfections increased substantially after Omicron variants emerged. Large-scale community-based comparisons across multiple Omicron waves of reinfection characteristics, risk factors, and protection afforded by previous infection and vaccination, are limited. Here we studied ~45,000 reinfections from the UK’s national COVID-19 Infection Survey and quantified the risk of reinfection in multiple waves, including those driven by BA.1, BA.2, BA.4/5, and BQ.1/CH.1.1/XBB.1.5 variants. Reinfections were associated with lower viral load and lower percentages of self-reporting symptoms compared with first infections. Across multiple Omicron waves, estimated protection against reinfection was significantly higher in those previously infected with more recent than earlier variants, even at the same time from previous infection. Estimated protection against Omicron reinfections decreased over time from the most recent infection if this was the previous or penultimate variant (generally within the preceding year). Those 14–180 days after receiving their most recent vaccination had a lower risk of reinfection than those >180 days from their most recent vaccination. Reinfection risk was independently higher in those aged 30–45 years, and with either low or high viral load in their most recent previous infection. Overall, the risk of Omicron reinfection is high, but with lower severity than first infections; both viral evolution and waning immunity are independently associated with reinfection
Antibody responses to SARS-CoV-2 vaccines in 45,965 adults from the general population of the United Kingdom
We report that in a cohort of 45,965 adults, who were receiving either the ChAdOx1 or the BNT162b2 SARS-CoV-2 vaccines, in those who had no prior infection with SARS-CoV-2, seroconversion rates and quantitative antibody levels after a single dose were lower in older individuals, especially in those aged >60 years. Two vaccine doses achieved high responses across all ages. Antibody levels increased more slowly and to lower levels with a single dose of ChAdOx1 compared with a single dose of BNT162b2, but waned following a single dose of BNT162b2 in older individuals. In descriptive latent class models, we identified four responder subgroups, including a ‘low responder’ group that more commonly consisted of people aged >75 years, males and individuals with long-term health conditions. Given our findings, we propose that available vaccines should be prioritized for those not previously infected and that second doses should be prioritized for individuals aged >60 years. Further data are needed to better understand the extent to which quantitative antibody responses are associated with vaccine-mediated protection
Antibody responses and correlates of protection in the general population after two doses of the ChAdOx1 or BNT162b2 vaccines
Antibody responses are an important part of immunity after Coronavirus Disease 2019 (COVID-19) vaccination. However, antibody trajectories and the associated duration of protection after a second vaccine dose remain unclear. In this study, we investigated anti-spike IgG antibody responses and correlates of protection after second doses of ChAdOx1 or BNT162b2 vaccines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the United Kingdom general population. In 222,493 individuals, we found significant boosting of anti-spike IgG by the second doses of both vaccines in all ages and using different dosing intervals, including the 3-week interval for BNT162b2. After second vaccination, BNT162b2 generated higher peak levels than ChAdOX1. Older individuals and males had lower peak levels with BNT162b2 but not ChAdOx1, whereas declines were similar across ages and sexes with ChAdOX1 or BNT162b2. Prior infection significantly increased antibody peak level and half-life with both vaccines. Anti-spike IgG levels were associated with protection from infection after vaccination and, to an even greater degree, after prior infection. At least 67% protection against infection was estimated to last for 2–3 months after two ChAdOx1 doses, for 5–8 months after two BNT162b2 doses in those without prior infection and for 1–2 years for those unvaccinated after natural infection. A third booster dose might be needed, prioritized to ChAdOx1 recipients and those more clinically vulnerable
SARS-CoV-2 antibody trajectories after a single COVID-19 vaccination with and without prior infection
Given high SARS-CoV-2 incidence, coupled with slow and inequitable vaccine roll-out in many settings, there is a need for evidence to underpin optimum vaccine deployment, aiming to maximise global population immunity. We evaluate whether a single vaccination in individuals who have already been infected with SARS-CoV-2 generates similar initial and subsequent antibody responses to two vaccinations in those without prior infection. We compared anti-spike IgG antibody responses after a single vaccination with ChAdOx1, BNT162b2, or mRNA-1273 SARS-CoV-2 vaccines in the COVID-19 Infection Survey in the UK general population. In 100,849 adults median (50 (IQR: 37–63) years) receiving at least one vaccination, 13,404 (13.3%) had serological/PCR evidence of prior infection. Prior infection significantly boosted antibody responses, producing higher peak levels and/or longer half-lives after one dose of all three vaccines than those without prior infection receiving one or two vaccinations. In those with prior infection, the median time above the positivity threshold was >1 year after the first vaccination. Single-dose vaccination targeted to those previously infected may provide at least as good protection to two-dose vaccination among those without previous infection
Community prevalence of SARS-CoV-2 in England from April to November, 2020: results from the ONS Coronavirus Infection Survey
Background: Decisions about the continued need for control measures to contain the spread of severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2) rely on accurate and up-to-date information about the number of people
testing positive for SARS-CoV-2 and risk factors for testing positive. Existing surveillance systems are generally not
based on population samples and are not longitudinal in design.
Methods: Samples were collected from individuals aged 2 years and older living in private households in England that
were randomly selected from address lists and previous Office for National Statistics surveys in repeated crosssectional household surveys with additional serial sampling and longitudinal follow-up. Participants completed a
questionnaire and did nose and throat self-swabs. The percentage of individuals testing positive for SARS-CoV-2 RNA
was estimated over time by use of dynamic multilevel regression and poststratification, to account for potential
residual non-representativeness. Potential changes in risk factors for testing positive over time were also assessed.
The study is registered with the ISRCTN Registry, ISRCTN21086382.
Findings: Between April 26 and Nov 1, 2020, results were available from 1 191 170 samples from 280327 individuals; 5231
samples were positive overall, from 3923 individuals. The percentage of people testing positive for SARS-CoV-2 changed
substantially over time, with an initial decrease between April 26 and June 28, 2020, from 0·40% (95% credible interval
0·29–0·54) to 0·06% (0·04–0·07), followed by low levels during July and August, 2020, before substantial increases at
the end of August, 2020, with percentages testing positive above 1% from the end of October, 2020. Having a patient facing role and working outside your home were important risk factors for testing positive for SARS-CoV-2 at the end of
the first wave (April 26 to June 28, 2020), but not in the second wave (from the end of August to Nov 1, 2020). Age (young
adults, particularly those aged 17–24 years) was an important initial driver of increased positivity rates in the second
wave. For example, the estimated percentage of individuals testing positive was more than six times higher in those
aged 17–24 years than in those aged 70 years or older at the end of September, 2020. A substantial proportion of
infections were in individuals not reporting symptoms around their positive test (45–68%, dependent on calendar time.
Interpretation: Important risk factors for testing positive for SARS-CoV-2 varied substantially between the part of the
first wave that was captured by the study (April to June, 2020) and the first part of the second wave of increased
positivity rates (end of August to Nov 1, 2020), and a substantial proportion of infections were in individuals not
reporting symptoms, indicating that continued monitoring for SARS-CoV-2 in the community will be important for
managing the COVID-19 pandemic moving forwards
Tracing traditions: patterns of technological innovation and the circulation of copper in Southwest Asia from the 8th to 1st millennia BCE
The regions of Southwest Asia during the Late Chalcolithic and Bronze Age were inextricably linked through trade and culture expansion, but also in their technological development. This thesis presents the results of a large-scale synthesis of published chemical data from the region from the beginning of the use of metal in the 8th millennium BCE to the start of the Iron Age in the early 1st millennium BCE. Change and continuity in alloying tradition, copper-composition, and human interaction with the material are analysed by the application of two âOxford Systemâ methodologies and Kuijpersâ Perceptive Categories. The resultant patterns in the copper-base assemblage are visible across space and time, and it is the aim of this thesis to marry these alterations in approach or access to material with the wider archaeological context. This large-scale approach has also drawn out aspects of technology which have, until now, generally been regarded as isolated and sporadic regional finds. A pan-regional approach has revealed they are in fact part of wider phenomena. The study of these outliers opens up the prospect for deeper insight into human interaction with and technological approach to material throughout the development of ancient metallurgy.</p