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Euro Surveill ; 27(1)2022 01.
Article in English | MEDLINE | ID: covidwho-1613512


Serum samples were collected pre- and post-booster vaccination with Comirnaty in 626 participants (aged ≥ 50 years) who had received two Comirnaty doses < 30 days apart, two Comirnaty doses ≥ 30 days apart or two Vaxzevria doses ≥ 30 days apart. Irrespective of primary vaccine type or schedule, spike antibody GMTs peaked 2-4 weeks after second dose, fell significantly ≤ 38 weeks later and rose above primary immunisation GMTs 2-4 weeks post-booster. Higher post-booster responses were observed with a longer interval between primary immunisation and boosting.

COVID-19 Vaccines , COVID-19 , Humans , London , SARS-CoV-2 , United Kingdom
Nat Commun ; 12(1): 7217, 2021 Dec 10.
Article in English | MEDLINE | ID: covidwho-1565716


The UK prioritised delivery of the first dose of BNT162b2 (Pfizer/BioNTech) and AZD1222 (AstraZeneca) vaccines by extending the interval between doses up to 12 weeks. In 750 participants aged 50-89 years, we here compare serological responses after BNT162b2 and AZD1222 vaccination with varying dose intervals, and evaluate these against real-world national vaccine effectiveness (VE) estimates against COVID-19 in England. We show that antibody levels 14-35 days after dose two are higher in BNT162b2 recipients with an extended vaccine interval (65-84 days) compared with those vaccinated with a standard (19-29 days) interval. Following the extended schedule, antibody levels were 6-fold higher at 14-35 days post dose 2 for BNT162b2 than AZD1222. For both vaccines, VE was higher across all age-groups from 14 days after dose two compared to one dose, but the magnitude varied with dose interval. Higher dose two VE was observed with >6 week interval between BNT162b2 doses compared to the standard schedule. Our findings suggest higher effectiveness against infection using an extended vaccine schedule. Given global vaccine constraints these results are relevant to policymakers.

Preprint in English | EuropePMC | ID: ppcovidwho-292973


Importance: There are limited data on immune responses after COVID-19 vaccine boosters in individuals receiving primary immunisation with BNT162b2 (Pfizer-BioNTech) or AZD1222 (AstraZeneca) Objective: To assess SARS-CoV-2 antibody responses before and after booster vaccination with BNT162b2 in adults receiving two BNT162b2 or AZD1222 vaccine doses at least 6 months previously, as part of the United Kingdom national immunisation schedule Design: Prospective, cohort study Setting: London, England Participants: 750 immunocompetent adults aged ≥50 years Interventions: A single dose of BNT162b2 administered at least six months after primary immunisation with two doses of BNT162b2 given <30 days apart (BNT162b2-control) or ≥30 days apart (BNT162b2-extended) compared to AZD1222 given ≥30 days apart (AZD1222-extended) Main Outcome and Measures: SARS-CoV-2 spike protein antibody geometric mean titres (GMTs) before and 2-4 weeks after booster Results: Of 750 participants, 626 provided serum samples for up to 38 weeks after their second vaccine dose. Antibody GMTs peaked at 2-4 weeks after the second dose, before declining by 68% at 36-38 weeks after dose 2 for BNT162b2-control participants, 85% at 24-29 weeks for BNT162b2-extended participants and 78% at 24-29 weeks for AZD1222-extended participants. Antibody GMTs was highest in BNT162b2-extended participants (942 [95%CI, 797-1113]) than AZD1222-extended (183 [124-268]) participants at 24-29 weeks or BNT162b2-control participants at 36-38 weeks (208;95%CI, 150-289). At 2-4 weeks after booster, GMTs were significantly higher than after primary vaccination in all three groups: 18,104 (95%CI, 13,911-23,560;n=47) in BNT162b2-control (76.3-fold), 13,980 (11,902-16,421;n=118) in BNT162b2-extended (15.9-fold) and 10,799 (8,510-13,704;n=43) in AZD1222-extended (57.2-fold) participants. BNT162b2-control participants (median:262 days) had a longer interval between primary and booster doses than BNT162b2-extended or AZD1222-extended (both median:186 days) participants. Conclusions and Relevance: We observed rapid serological responses to boosting with BNT162b2, irrespective of vaccine type or schedule used for primary immunisation, with higher post-booster responses with longer interval between primary immunisation and boosting. Boosters will not only provide additional protection for those at highest risk of severe COVID-19 but also prevent infection and, therefore, interrupt transmission, thereby reducing infections rates in the population. Ongoing surveillance will be important for monitoring the duration of protection after the booster.

The International Migration Review ; 55(3):640-659, 2021.
Article in English | ProQuest Central | ID: covidwho-1352609


Border closures associated with COVID-19 constitute a response to an exogenous shock unrelated to migration. In this IMR Dispatch, we argue that the impact of policies initially implemented to halt movement and curb the spread of the disease will nonetheless have medium- and longer term consequences for international migration. Specifically, we argue that these initial border restrictions have set in motion demographic and sociological processes that are likely to culminate in greater support for restricting future migration. Based on demographic evidence, we posit that after extended suppression of migration, OECD countries and Russia will see a migration spike, akin to a “baby boom” for fertility rebounds. Drawing on sociological theory and research, we hypothesize that these spikes in migration will increase anti-immigrant sentiment among native-born residents in destination countries and mobilize political support for reintroducing restrictive migration policies — triggering a feedback loop. In an effort to help facilitate future research and empirical tests of our model, we identify key concepts, processes, and data sources for the analysis of the pandemic’s impact on international migration over time.

Animals (Basel) ; 11(7)2021 Jul 02.
Article in English | MEDLINE | ID: covidwho-1295737


Amphibians are an understudied group in the zoo-focussed literature. Whilst commonly housed in specialist exhibits and of real conservation value due to the global extinction crisis, amphibian welfare is not often investigated empirically in zoo settings. The limited research that is available suggests that enclosure design (structure, planting and naturalistic theming) has a positive impact on the time that amphibians will be on show to visitors. However, the categorisation of any "visitor effect" (i.e., influences of visitor presence on amphibian activity and time on display) is hard to find. The COVID-19 pandemic forced the closure of zoological organisations in the UK for several months from March 2020, with gradual re-openings from the summer into autumn and winter. This event provided a unique opportunity to study the effect of the lack of visitors, the presence of essential zoo staff only, the wider return of organisational staff, and then the return of visitors over a prolonged period. This project at WWT Slimbridge Wetlands Centre assessed the number of individuals of six species of amphibian-common toad (Bufo bufo), common frog (Rana temporaria), smooth newt (Lissotriton vulgaris), pool frog (Pelophylax lessonae), golden mantella (Mantella aurantiaca) and golden poison dart frog (Phyllobates terribilis)-visible to observers under different conditions. All amphibians were housed in a purpose-built indoor exhibit of individual enclosures and were recorded when visible (as a proportion of the total population of the enclosure) during closure, the return of extra centre staff and visitor periods. The results showed species-specific differences in visibility, with some species of amphibian being more likely to be on view when the presence of people at their enclosure was less likely or in smaller numbers. Such differences are likely related to the specific camouflage or anti-predation tactics in these focal species. Further study to quantify amphibian sensitivity to, and perception of, environmental change caused by public presence (e.g., light levels and sound) would be useful welfare-themed research extensions. Our results can help inform husbandry, collection planning and amphibian enclosure design to reduce any noticeable visitor effects, and provide a useful benchmark for further, more complex, welfare assessment measures.

Euro Surveill ; 26(12)2021 03.
Article in English | MEDLINE | ID: covidwho-1154193


Sera were collected from 185 adults aged ≥ 70 years in London to evaluate the immune response to COVID-19 vaccines. A single dose of Pfizer/BioNtech vaccine resulted in > 94% seropositivity after 3 weeks in naïve individuals using the Roche Spike antibody assay, while two doses produced very high spike antibody levels, significantly higher than convalescent sera from mild-to-moderate PCR-confirmed adult cases. Our findings support the United Kingdom's approach of prioritising the first dose and delaying the second dose of COVID-19 vaccine.

Antibodies, Viral/blood , Antibody Formation , COVID-19 Vaccines/immunology , COVID-19/prevention & control , Aged , Aged, 80 and over , Humans , London