Waning, Boosting and a Path to Endemicity for SARS-CoV-2

Keeling, Matthew James; Thomas, Amy; Hill, Edward M.; Thompson, Robin N; Dyson, Louise; Tildesley, Michael J.; Moore, Sam

doi:10.1101/2021.11.05.21265977

Cited by 16 publications

(42 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our assumptions in Roadmap 3 [15] about social mixing associated with Steps 3 and 4 significantly underestimated the level of precautionary behaviour (Fig. 5, top panel), leading to modelled outputs with greater transmission than was realised.…”

Section: Resultsmentioning

confidence: 99%

“…From Roadmap 3 Fig. 10 [15], which considered the impact of social mixing and hence transmission in Step 4. Top panel shows the inferred level of precautionary behaviour (grey) together with the assumed default levels from Roadmap 3 [15].…”

Section: Resultsmentioning

confidence: 99%

“…While the assumption of a step-change responding to relaxing measures was supported by the sudden increases in precautionary behaviour when measures were initially introduced, we now observe that the response to the introduction of measures was much quicker than to the relaxation of measures. Later models [17, 18] assumed a more gradual response to the relaxation steps; but population behaviour remains unpredictable over long timescales. Although we have seen a gradual decline in the inferred precautionary behaviour (and hence an increase in social mixing) since the end of the January 2021 lockdown (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…In general, Roadmap modelling suggested that hospital admissions would not rise to the extreme levels observed during the first and second waves (with peak admissions of 3099 and 4134 in England respectively) following the relaxation steps. The exception to this was Roadmap 4a [16, 45], where uncertainty over the Delta variant (especially the protection afforded by vaccination) led to a range of projections many with high peak hospital admissions (Fig. 6).…”

Section: Discussionmentioning

confidence: 99%

See 3 more Smart Citations

Comparison of the 2021 COVID-19 Roadmap Projections against Public Health Data in England

Keeling

Dyson

Tildesley

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Control and mitigation of the COVID-19 pandemic in England has relied on a combination of vaccination and non-pharmaceutical interventions (NPIs) such as closure of non-essential shops and leisure activities, closure of schools, social distancing, mask wearing, testing followed by isolation and general public health awareness. Some of these measures are extremely costly (both economically and socially), so it is important that they are relaxed promptly but without overwhelming already burdened health services. The eventual policy was a Roadmap of four relaxation steps throughout 2021, taking England from lock-down to the cessation of all restrictions on social interaction; with a minimum of five weeks between each step to allow the data to reflect the changes in restrictions and the results to analysed. Here we present a retrospective analysis of our six Roadmap documents generated in 2021 to assess the likely impacts of future relaxation steps in England. In each case we directly compare results generated at the time with more recent public health data (primarily hospital admissions, but also hospital occupancy and death) to understand discrepancies and potential improvements. We conclude that, in general, the model projections generated a reliable estimation of medium-term hospital admission trends, with the data points up to September 2021 generally lying within our 95% projection intervals. The greatest uncertainties in the modelled scenarios came from estimates of vaccine efficacy, hampered by the lack of data in the early stages of the Alpha and Delta variant waves, and from assumptions about human behaviour in the face of changing restrictions and changing risk. These are clearly avenues for future study.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of the 2021 COVID-19 Roadmap Projections against Public Health Data in England

Keeling

Dyson

Tildesley

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Given this observation, from September 2021 booster (third) doses were offered to individuals who had received their second dose of vaccine more than six months ago. Both waning and boosters are included in the updated model framework [51].…”

Section: Methodsmentioning

confidence: 99%

An assessment of the vaccination of school-aged children in England

Keeling

Moore

2022

Preprint

Self Cite

View full text Add to dashboard Cite

BACKGROUND. Children and young persons are known to have a high number of close interactions, oftenwithin the school environment, which can facilitate rapid spread of infection; yet for SARS-CoV-2 it isthe elderly and vulnerable that suffer the greatest health burden. Vaccination, initially targeting theelderly and vulnerable but later expanded to the entire adult population, has been transformative inthe control of SARS-CoV-2 in England. However, early concerns over adverse events and the lower riskassociated with infection in younger individuals means that the expansion of the vaccine programmeto those under 18 year of age needs to be rigorously and quantitatively assessed. METHODS. Here, using a bespoke mathematical model matched to case and hospital data for England,we consider the potential impact of vaccinating 12-17 and 5-11 year olds. This analysis is reportedfrom an early model (generated in June 2021) that formed part of the evidence base for the decisionsin England, and a later model (from November 2021) that benefits from a richer understanding ofvaccine efficacy, greater knowledge of the Delta variant wave and uses data on the rate of vaccineadministration. For both models we consider the population wide impact of childhood vaccination aswell as the specific impact on the age-group targeted for vaccination. RESULTS. Projections from June suggested that an expansion of the vaccine programme to those 12-17years old could generate substantial reductions in infection, hospital admission and deaths in the en-tire population, depending on population behaviour following the relaxation of control measures. Thebenefits within the 12-17 year old cohort were less marked, saving between 656 and 1077 (95% predic-tion interval 281-2260) hospital admissions and between 22 and 38 (95% PI 9-91) deaths dependingon assumed population behaviour. For the more recent model, the benefits within this age group arereduced, saving on average 631 (95% PI 304-1286) hospital admissions and 11 (95% PI 5-28) deathsfor 80% vaccine uptake, while the benefits to the wider population represent a reduction of 8-10% inhospital admissions and deaths. The vaccination of 5-11 year olds is projected to have a far smallerimpact, in part due to the later roll-out of vaccines to this age-group. CONCLUSIONS. Vaccination of 12-17 year olds and 5-11 year olds is projected to generate a reductionin infection, hospital admission and deaths for both the age-groups involved and the population ingeneral. For any decision involving childhood vaccination, these benefits needs to be balanced againstpotential adverse events from the vaccine, the operational constraints on delivery and the potentialfor diverting resources from other public health campaigns.

show abstract