TY - JOUR
T1 - Exponential growth, high prevalence of SARS-CoV-2, and vaccine effectiveness associated with the Delta variant
AU - Elliott, Paul
AU - Haw, David
AU - Wang, Haowei
AU - Eales, Oliver
AU - Walters, Caroline E.
AU - Ainslie, Kylie E. C.
AU - Atchison, Christina
AU - Fronterre, Claudio
AU - Diggle, Peter J.
AU - Page, Andrew J.
AU - Trotter, Alexander J.
AU - Prosolek, Sophie J.
AU - The COVID-19 Genomics UK (COG-UK) Consortium
AU - Ashby, Deborah
AU - Donnelly, Christl A.
AU - Barclay, Wendy
AU - Taylor, Graham
AU - Cooke, Graham
AU - Ward, Helen
AU - Darzi, Ara
AU - Riley, Steven
AU - Davidson, Rosemary
PY - 2021/12/17
Y1 - 2021/12/17
N2 - Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections were rising during early summer 2021 in many countries as a result of the Delta variant. We assessed reverse transcription polymerase chain reaction swab positivity in the Real-time Assessment of Community Transmission-1 (REACT-1) study in England. During June and July 2021, we observed sustained exponential growth with an average doubling time of 25 days, driven by complete replacement of the Alpha variant by Delta and by high prevalence at younger, less-vaccinated ages. Prevalence among unvaccinated people [1.21% (95% credible interval 1.03%, 1.41%)] was three times that among double-vaccinated eople [0.40%(95% credible interval 0.34%, 0.48%]. However, after adjusting for age and other variables, vaccine effectiveness for double-vaccinated people was estimated at between ∼50% and ∼60% during this period in England. Increased socialmixing in the presence of Delta had the potential to generate sustained growth in infections, even at high levels of vaccination.
AB - Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections were rising during early summer 2021 in many countries as a result of the Delta variant. We assessed reverse transcription polymerase chain reaction swab positivity in the Real-time Assessment of Community Transmission-1 (REACT-1) study in England. During June and July 2021, we observed sustained exponential growth with an average doubling time of 25 days, driven by complete replacement of the Alpha variant by Delta and by high prevalence at younger, less-vaccinated ages. Prevalence among unvaccinated people [1.21% (95% credible interval 1.03%, 1.41%)] was three times that among double-vaccinated eople [0.40%(95% credible interval 0.34%, 0.48%]. However, after adjusting for age and other variables, vaccine effectiveness for double-vaccinated people was estimated at between ∼50% and ∼60% during this period in England. Increased socialmixing in the presence of Delta had the potential to generate sustained growth in infections, even at high levels of vaccination.
UR - http://www.scopus.com/inward/record.url?scp=85120291789&partnerID=8YFLogxK
U2 - 10.1126/science.abl9551
DO - 10.1126/science.abl9551
M3 - Article
C2 - 34726481
AN - SCOPUS:85120291789
VL - 374
JO - Science
JF - Science
SN - 0036-8075
IS - 6574
M1 - abl9551
ER -
