Protection against SARS-CoV-2 after Covid-19 Vaccination and Previous Infection.

BACKGROUND: The duration and effectiveness of immunity from infection with and vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are relevant to pandemic policy interventions, including the timing of vaccine boosters. METHODS: We investigated the duration and effectiveness of immunity in a prospective cohort of asymptomatic health care workers in the United Kingdom who underwent routine polymerase-chain-reaction (PCR) testing. Vaccine effectiveness (≤10 months after the first dose of vaccine) and infection-acquired immunity were assessed by comparing the time to PCR-confirmed infection in vaccinated persons with that in unvaccinated persons, stratified according to previous infection status. We used a Cox regression model with adjustment for previous SARS-CoV-2 infection status, vaccine type and dosing interval, demographic characteristics, and workplace exposure to SARS-CoV-2. RESULTS: Of 35,768 participants, 27% (9488) had a previous SARS-CoV-2 infection. Vaccine coverage was high: 95% of the participants had received two doses (78% had received BNT162b2 vaccine [Pfizer-BioNTech] with a long interval between doses, 9% BNT162b2 vaccine with a short interval between doses, and 8% ChAdOx1 nCoV-19 vaccine [AstraZeneca]). Between December 7, 2020, and September 21, 2021, a total of 2747 primary infections and 210 reinfections were observed. Among previously uninfected participants who received long-interval BNT162b2 vaccine, adjusted vaccine effectiveness decreased from 85% (95% confidence interval [CI], 72 to 92) 14 to 73 days after the second dose to 51% (95% CI, 22 to 69) at a median of 201 days (interquartile range, 197 to 205) after the second dose; this effectiveness did not differ significantly between the long-interval and short-interval BNT162b2 vaccine recipients. At 14 to 73 days after the second dose, adjusted vaccine effectiveness among ChAdOx1 nCoV-19 vaccine recipients was 58% (95% CI, 23 to 77) - considerably lower than that among BNT162b2 vaccine recipients. Infection-acquired immunity waned after 1 year in unvaccinated participants but remained consistently higher than 90% in those who were subsequently vaccinated, even in persons infected more than 18 months previously. CONCLUSIONS: Two doses of BNT162b2 vaccine were associated with high short-term protection against SARS-CoV-2 infection; this protection waned considerably after 6 months. Infection-acquired immunity boosted with vaccination remained high more than 1 year after infection. (Funded by the U.K. Health Security Agency and others; ISRCTN Registry number, ISRCTN11041050.).

Early Warning Surveillance for SARS-CoV-2 Omicron Variants, United Kingdom, November 2021-September 2022.

Since June 2020, the SARS-CoV-2 Immunity and Reinfection Evaluation (SIREN) study has conducted routine PCR testing in UK healthcare workers and sequenced PCR-positive samples. SIREN detected increases in infections and reinfections and delected Omicron subvariant waves emergence contemporaneous with national surveillance. SIREN's sentinel surveillance methods can be used for variant surveillance.

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

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.

COVID-19 mortality among people with diagnosed HIV compared to those without during the first wave of the COVID-19 pandemic in England.

OBJECTIVES: We describe COVID-19 mortality among people with and without HIV during the first wave of the pandemic in England. METHODS: National surveillance data on adults (aged ≥ 15 years) with diagnosed HIV resident in England were linked to national COVID-19 mortality surveillance data (2 March 2020-16 June 2020); HIV clinicians verified linked cases and provided information on the circumstances of death. We present COVID-19 mortality rates by HIV status, using negative binomial regression to assess the association between HIV and mortality, adjusting for gender, age and ethnicity. RESULTS: Overall, 99 people with HIV, including 61 of black ethnicity, died of/with COVID-19 (107/100 000) compared with 49 483 people without HIV (109/100 000). Compared to people without HIV, higher COVID-19 mortality rates were observed in people with HIV of black (188 vs. 122/100 000) and Asian (131 vs. 77.0/100 000) ethnicity, and in both younger (15-59 years: 58.3 vs. 10.2/100 000) and older (≥ 60 years: 434 vs. 355/100 000) people. After adjustment for demographic factors, people with HIV had a higher COVID-19 mortality risk than those without (2.18; 95% CI: 1.76-2.70). Most people with HIV who died of/with COVID-19 had suppressed HIV viraemia (91%) and at least one comorbidity reported to be associated with poor COVID-19 outcomes (87%). CONCLUSIONS: In the first wave of the pandemic in England, COVID-19 mortality among people with HIV was low, but was higher than in those without HIV, after controlling for demographic factors. This supports the strategy of prioritizing COVID-19 vaccination for people with HIV and strongly encouraging its uptake, especially in those of black and Asian ethnicity.

The success of HIV combination prevention: The Dean Street model.

The 56 Dean Street combination prevention model, a strong engagement with the LGBTQI community and flexible services adapted to users' changing needs led to an 80% drop in HIV diagnoses in gay, bisexual and other men who have sex with men (GBMSM) from 2015 to 2017. We describe the service changes at 56 Dean Street since 2012 which resulted in an increase in the frequency of HIV testing, the introduction of pre-exposure prophylaxis, earlier HIV diagnosis and a shorter time to viral suppression in those living with HIV. This model could be adapted to deliver similar results in those settings of high HIV prevalence among GBMSM and where access to technological innovation in healthcare and engagement with the community can be achieved.

Prevalence and impact of persistent symptoms following SARS-CoV-2 infection among healthcare workers: A cross-sectional survey in the SIREN cohort.

INTRODUCTION: Following SARS-CoV-2 infection, some patients experience a range of long-lasting symptoms, with a specific burden on their lives and ability to work. AIM: We describe the prevalence and impact of persistent symptoms pre-/post-vaccination in SIREN study participants. METHODS: A cross-sectional study of SARS-CoV-2 positive participants was carried out within SIREN, a frequently tested UK healthcare worker cohort with vaccination and demographic data available. Participants with a SARS-CoV-2 positive PCR or anti-SARS-CoV-2 sample between 01 March 2020 and 31 September 2022 were asked via a questionnaire about symptoms and days absent from work following infection. Responses were excluded if infection dates were inconsistent with study records or missing key data. Symptom type/duration and whether infection occurred pre-/post-vaccination and during which variant period were described. Logistic regression was used to estimate factors associated with persistent symptoms (>12 weeks), adjusting for vaccination and demographic factors. The median days absent from work were also determined. RESULTS: Of 16,599 invitations, 6677 participants responded, and 5053 were included in the analysis. The prevalence of persistent symptoms (symptoms lasting over 12 weeks) differed by infection episode; highest for first infections (32.7%; 1557/4767) compared to second (21.6%; 214/991) and third infections (21.6%; 16/74). Most frequently reported symptoms were fatigue, tiredness, shortness of breath and difficulty concentrating. A higher prevalence of persistent symptoms was reported during the Wild-type variant period compared to the other variant periods (52.9% Wild-type vs. 20.7% Omicron, for any symptom reported during their first infection). Overall, persistent symptoms were higher among unvaccinated participants (unvaccinated 38.1% vs vaccinated 22.0%). Multivariable analysis showed that participants were less likely to report persistent symptoms in infections occurring after vaccination compared to those with an infection before vaccination in the Alpha/Delta and Omicron periods (Alpha/Delta: adjusted Odds Ratio (aOR) 0.66, CI 95% 0.51-0.87, p = aOR 0.07, CI 95% 0.01-0.65, p = 0.02). About half of participants reported that their persistent symptoms impacted their day-to-day (51.8%) and work-related (42.1%) activities 'a little', and 24.0% and 14.4% reported that the impact was 'A lot'. 8.9% reported they had reduced their working hours, and 13.9% had changed their working pattern. DISCUSSION: Persistent symptoms were frequent in our cohort, and there was a reduction in symptom duration in those with multiple infection episodes during later variant periods and post-vaccination. The impact of persistent symptoms resulting in reducing working hours or adjusting working patterns has important implications for workforce resilience. UK healthcare workers were highly exposed during the pandemic, demonstrating a significant burden.

Protection of vaccine boosters and prior infection against mild/asymptomatic and moderate COVID-19 infection in the UK SIREN healthcare worker cohort: October 2023 to March 2024.

OBJECTIVES: Bivalent original/BA.4-5 and monovalent XBB.1.5 mRNA boosters were offered to UK healthcare workers (HCWs) in the autumn of 2023. We aimed to estimate booster vaccine effectiveness (VE) and post-infection immunity among the SIREN HCW cohort over the subsequent 6-month period of XBB.1.5 and JN.1 variant circulation. METHODS: Between October 2023 to March 2024, 2867 SIREN study participants tested fortnightly for SARS-CoV-2 and completed symptoms questionnaires. We used multi-state models, adjusted for vaccination, prior infection, and demographic covariates, to estimate protection against mild/asymptomatic and moderate SARS-CoV-2 infection. RESULTS: Half of the participants (1422) received a booster during October 2023 (280 bivalent, 1142 monovalent), and 536 (19%) had a PCR-confirmed infection over the study period. Bivalent booster VE was 15.1% (-55.4 to 53.6%) at 0-2 months and 4.2% (-46.4 to 37.3%) at 2-4 months post-vaccination. Monovalent booster VE was 44.2% (95% CI 21.7 to 60.3%) at 0-2 months, and 24.1% (-0.7 to 42.9%) at 2-4 months. VE was greater against moderate infection than against mild/asymptomatic infection, but neither booster showed evidence of protection after 4 months. Controlling for vaccination, compared to an infection >2 years prior, infection within the past 6 months was associated with 58.6% (30.3 to 75.4%) increased protection against moderate infection and 38.5% (5.8 to 59.8%) increased protection against mild/asymptomatic infection. CONCLUSIONS: Monovalent XBB.1.5 boosters provided short-term protection against SARS-CoV-2 infection, particularly against moderate symptoms. Vaccine formulations that target the circulating variant may be suitable for inclusion in seasonal vaccination campaigns among HCWs.

Electronic health records to capture primary outcome measures: two case studies in HIV prevention research.

BACKGROUND: There is increasing interest in the use of electronic health records (EHRs) to improve the efficiency and cost-effectiveness of clinical trials, including the capture of outcome measures. MAIN TEXT: We describe our experience of using EHRs to capture the primary outcome measure - HIV infection or the diagnosis of HIV infection - in two randomised HIV prevention trials conducted in the UK. PROUD was a clinic-based trial evaluating pre-exposure prophylaxis (PrEP), and SELPHI was an internet-based trial evaluating HIV self-testing kits. The EHR was the national database of HIV diagnoses in the UK, curated by the UK Health Security Agency (UKHSA). In PROUD, linkage to the UKHSA database was performed at the end of the trial and identified five primary outcomes in addition to the 30 outcomes diagnosed by the participating clinics. Linkage also produced an additional 345 person-years follow-up, an increase of 27% over clinic-based follow-up. In SELPHI, new HIV diagnoses were primarily identified via UKHSA linkage, complemented by participant self-report through internet surveys. Rates of survey completion were low, and only 14 of the 33 new diagnoses recorded in the UKHSA database were also self-reported. Thus UKHSA linkage was essential for capturing HIV diagnoses and the successful conduct of the trial. CONCLUSIONS: Our experience of using the UKHSA database of HIV diagnoses as a source of primary outcomes in two randomised trials in the field of HIV prevention was highly favourable and encourages the use of a similar approach in future trials in this disease area.

Free HIV self-test for identification and linkage to care of previously undetected HIV infection in men who have sex with men in England and Wales (SELPHI): an open-label, internet-based, randomised controlled trial.

BACKGROUND: High levels of HIV testing in men who have sex with men remain key to reducing the incidence of HIV. We aimed to assess whether the offer of a single, free HIV self-testing kit led to increased HIV diagnoses with linkage to care. METHODS: SELPHI was an internet-based, open-label, randomised controlled trial that recruited participants via sexual and social networking sites. Eligibility criteria included being a man or trans woman (although trans women are reported separately); being resident in England or Wales, UK; being aged 16 years or older; having had anal intercourse with a man; not having a positive HIV diagnosis; and being willing to provide name, email address, date of birth, and consent to link to national HIV databases. Participants were randomly allocated (3:2) by computer-generated number sequence to receive a free HIV self-test kit (BT group) or to not receive this free kit (nBT group). Online surveys collected data at baseline, 2 weeks after enrolment (BT group only), 3 months after enrolment, and at the end of the study. The primary outcome was confirmed (linked to care) new HIV diagnosis within 3 months of enrolment, analysed by intention to treat. Those assessing the primary outcome were masked to allocation. This study is registered with the ISRCTN Clinical Trials Register, number ISRCTN20312003. FINDINGS: 10 111 participants (6049 in BT group and 4062 in nBT group) enrolled between Feb 16, 2017, and March 1, 2018. The median age of participants was 33 years (IQR 26-44 years); 9000 (89%) participants were White; 8118 (80%) participants were born in the UK; 81 (1%) participants were transgender men; 4706 (47%) participants were university educated; 1537 (15%) participants had never been tested for HIV; and 389 (4%) participants were taking pre-exposure prophylaxis. At enrolment, 7282 (72%) participants reported condomless anal sex with at least one male partner in the previous 3 months. In the BT group, of the 4511 participants for whom HIV testing information was available, 4263 (95%) reported having used the free HIV self-test kit within 3 months.Within 3 months of enrolment there were 19 confirmed new HIV diagnoses (0·31%) in 6049 participants in the BT group and 15 (0·37%) of 4062 in the nBT group (p=0·64). INTERPRETATION: The offer of a single, free HIV self-test did not lead to increased rates of new HIV diagnoses, which could reflect decreasing HIV incidence rates in the UK. Nonetheless, the offer of a free HIV self-testing kit resulted in high HIV testing rates, indicating that self-testing is an attractive testing option for a large group of men who have sex with men. FUNDING: UK National Institute for Health and Care Research.