COVID-19 pandemic dynamics in India, the SARS-CoV-2 Delta variant and implications for vaccination.
J R Soc Interface
; 19(191): 20210900, 2022 06.
Article
in English
| MEDLINE | ID: covidwho-1878854
ABSTRACT
The Delta variant is a major SARS-CoV-2 variant of concern first identified in India. To better understand COVID-19 pandemic dynamics and Delta, we use multiple datasets and model-inference to reconstruct COVID-19 pandemic dynamics in India during March 2020-June 2021. We further use the large discrepancy in one- and two-dose vaccination coverage in India (53% versus 23% by end of October 2021) to examine the impact of vaccination and whether prior non-Delta infection can boost vaccine effectiveness (VE). We estimate that Delta escaped immunity in 34.6% (95% CI 0-64.2%) of individuals with prior wild-type infection and was 57.0% (95% CI 37.9-75.6%) more infectious than wild-type SARS-CoV-2. Models assuming higher VE among non-Delta infection recoverees, particularly after the first dose, generated more accurate predictions than those assuming no such increases (best-performing VE setting:
90/95% versus 30/67% baseline for the first/second dose). Counterfactual modelling indicates that high vaccination coverage for first vaccine dose in India combined with the boosting of VE among recoverees averted around 60% of infections during July-mid-October 2021. These findings provide support to prioritizing first-dose vaccination in regions with high underlying infection rates, given continued vaccine shortages and new variant emergence.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
SARS-CoV-2
/
COVID-19
Type of study:
Observational study
/
Prognostic study
Topics:
Vaccines
/
Variants
Limits:
Humans
Country/Region as subject:
Asia
Language:
English
Journal:
J R Soc Interface
Year:
2022
Document Type:
Article
Affiliation country:
Rsif.2021.0900
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