Browsing by Author "Wilder-Smith, Annelies"
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Publication Duration of effectiveness of vaccines against SARS-CoV-2 infection and COVID-19 disease: results of a systematic review and meta-regression(2022) Feikin, Daniel R.; Higdon, Melissa M.; Abu-Raddad, Laith J.; Andrews, Nick; Araos, Rafael; Goldberg, Yair; Groome, Michelle J.; Huppert, Amit; O'Brien, Katherine L.; Smith, Peter G.; Wilder-Smith, Annelies; Zeger, Scott; Deloria Knoll, María; Patel, Minal K.Background: Knowing whether COVID-19 vaccine effectiveness wanes is crucial for informing vaccine policy, such as the need for and timing of booster doses. We aimed to systematically review the evidence for the duration of protection of COVID-19 vaccines against various clinical outcomes, and to assess changes in the rates of breakthrough infection caused by the delta variant with increasing time since vaccination. Methods: This study was designed as a systematic review and meta-regression. We did a systematic review of preprint and peer-reviewed published article databases from June 17, 2021, to Dec 2, 2021. Randomised controlled trials of COVID-19 vaccine efficacy and observational studies of COVID-19 vaccine effectiveness were eligible. Studies with vaccine efficacy or effectiveness estimates at discrete time intervals of people who had received full vaccination and that met predefined screening criteria underwent full-text review. We used random-effects meta-regression to estimate the average change in vaccine efficacy or effectiveness 1–6 months after full vaccination. Findings: Of 13 744 studies screened, 310 underwent full-text review, and 18 studies were included (all studies were carried out before the omicron variant began to circulate widely). Risk of bias, established using the risk of bias 2 tool for randomised controlled trials or the risk of bias in non-randomised studies of interventions tool was low for three studies, moderate for eight studies, and serious for seven studies. We included 78 vaccine-specific vaccine efficacy or effectiveness evaluations (Pfizer–BioNTech-Comirnaty, n=38; Moderna-mRNA-1273, n=23; Janssen-Ad26.COV2.S, n=9; and AstraZeneca-Vaxzevria, n=8). On average, vaccine efficacy or effectiveness against SARS-CoV-2 infection decreased from 1 month to 6 months after full vaccination by 21·0 percentage points (95% CI 13·9–29·8) among people of all ages and 20·7 percentage points (10·2–36·6) among older people (as defined by each study, who were at least 50 years old). For symptomatic COVID-19 disease, vaccine efficacy or effectiveness decreased by 24·9 percentage points (95% CI 13·4–41·6) in people of all ages and 32·0 percentage points (11·0–69·0) in older people. For severe COVID-19 disease, vaccine efficacy or effectiveness decreased by 10·0 percentage points (95% CI 6·1–15·4) in people of all ages and 9·5 percentage points (5·7–14·6) in older people. Most (81%) vaccine efficacy or effectiveness estimates against severe disease remained greater than 70% over time. Interpretation: COVID-19 vaccine efficacy or effectiveness against severe disease remained high, although it did decrease somewhat by 6 months after full vaccination. By contrast, vaccine efficacy or effectiveness against infection and symptomatic disease decreased approximately 20–30 percentage points by 6 months. The decrease in vaccine efficacy or effectiveness is likely caused by, at least in part, waning immunity, although an effect of bias cannot be ruled out. Evaluating vaccine efficacy or effectiveness beyond 6 months will be crucial for updating COVID-19 vaccine policy. Funding: Coalition for Epidemic Preparedness Innovations.Item Epidemic preparedness in urban settings: new challenges and opportunities(2020) Lee, Vernon J.; Ho, Marc; Wen Kai, Chen; Aguilera, Ximena; Heymann, David; Wilder-Smith, AnneliesItem Preparedness for emerging epidemic threats: a Lancet Infectious Diseases Commission(2020) Lee, Vernon; Aguilera, Ximena; Heymann, David; Wilder-Smith, Annelies; Lancet Infectious Diseases CommissionAt any time, an emerging, lethal, and highly transmissible pathogen might pose a risk of being spread globally because of the interconnectedness of the global population.1, 2 Emerging epidemic threats are occurring with increasing scale, duration, and effect, often disrupting travel and trade, and damaging both national and regional economies.3, 4 Even geographically limited outbreaks such as the Ebola virus disease in Africa might have a global effect. Preparing for epidemic threats is not a static or binary (prepared or unprepared) exercise, but a dynamic state reflecting the constantly changing world. Countries prepare in different ways based on their interpretation of disease risks and international agreements such as the International Health Regulations (IHR). The IHR were introduced in 1969 to prevent spread of specific serious diseases between countries and set out preparedness measures at international borders to stop disease spread. The 2005 revisions to the IHR reflect changes across multiple dimensions, requiring countries to develop preparedness capacities to detect and respond to outbreaks where and when they occur, supported by international partners to respond when outbreaks cannot be contained locally.5 However, disruptive factors have emerged at a greater pace over the past decade, creating a new ecology that requires novel strategies for preparedness. These factors include dealing with the increasing human population density and connectivity, harnessing novel data streams and new technological advances to manage epidemics, mitigating false information on social networks, to creating informal technical networks that can work together when political forces fail to do so. without epidemiological and clinical surveillance data is insufficient to show whether new SARS-CoV-2 variants are more transmissible, more lethal, or more capable of evading immunity, including vaccine-induced immunity.