TY - JOUR
T1 - Delta Variants of SARS-CoV-2 Cause Significantly Increased Vaccine Breakthrough COVID-19 Cases in Houston, Texas
AU - Christensen, Paul A.
AU - Olsen, Randall J.
AU - Long, S. Wesley
AU - Subedi, Sishir
AU - Davis, James J.
AU - Hodjat, Parsa
AU - Walley, Debbie R.
AU - Kinskey, Jacob C.
AU - Ojeda Saavedra, Matthew
AU - Pruitt, Layne
AU - Reppond, Kristina
AU - Shyer, Madison N.
AU - Cambric, Jessica
AU - Gadd, Ryan
AU - Thakur, Rashi M.
AU - Batajoo, Akanksha
AU - Mangham, Regan
AU - Pena, Sindy
AU - Trinh, Trina
AU - Yerramilli, Prasanti
AU - Nguyen, Marcus
AU - Olson, Robert
AU - Snehal, Richard
AU - Gollihar, Jimmy
AU - Musser, James M.
N1 - Funding Information:
Supported by the Houston Methodist Academic Institute Infectious Diseases Fund and supported in whole or in part with federal funds from the National Institute of Allergy and Infectious Diseases , NIH , Department of Health and Human Services ( 75N93019C00076 , J.J.D. and R.O.).
Publisher Copyright:
© 2022 American Society for Investigative Pathology
PY - 2022/2
Y1 - 2022/2
N2 - Genetic variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have repeatedly altered the course of the coronavirus disease 2019 (COVID-19) pandemic. Delta variants are now the focus of intense international attention because they are causing widespread COVID-19 globally and are associated with vaccine breakthrough cases. We sequenced 16,965 SARS-CoV-2 genomes from samples acquired March 15, 2021, through September 20, 2021, in the Houston Methodist hospital system. This sample represents 91% of all Methodist system COVID-19 patients during the study period. Delta variants increased rapidly from late April onward to cause 99.9% of all COVID-19 cases and spread throughout the Houston metroplex. Compared with all other variants combined, Delta caused a significantly higher rate of vaccine breakthrough cases (23.7% for Delta compared with 6.6% for all other variants combined). Importantly, significantly fewer fully vaccinated individuals required hospitalization. Vaccine breakthrough cases caused by Delta had a low median PCR cycle threshold value (a proxy for high virus load). This value was similar to the median cycle threshold value for unvaccinated patients with COVID-19 caused by Delta variants, suggesting that fully vaccinated individuals can transmit SARS-CoV-2 to others. Patients infected with Alpha and Delta variants had several significant differences. The integrated analysis indicates that vaccines used in the United States are highly effective in decreasing severe COVID-19, hospitalizations, and deaths.
AB - Genetic variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have repeatedly altered the course of the coronavirus disease 2019 (COVID-19) pandemic. Delta variants are now the focus of intense international attention because they are causing widespread COVID-19 globally and are associated with vaccine breakthrough cases. We sequenced 16,965 SARS-CoV-2 genomes from samples acquired March 15, 2021, through September 20, 2021, in the Houston Methodist hospital system. This sample represents 91% of all Methodist system COVID-19 patients during the study period. Delta variants increased rapidly from late April onward to cause 99.9% of all COVID-19 cases and spread throughout the Houston metroplex. Compared with all other variants combined, Delta caused a significantly higher rate of vaccine breakthrough cases (23.7% for Delta compared with 6.6% for all other variants combined). Importantly, significantly fewer fully vaccinated individuals required hospitalization. Vaccine breakthrough cases caused by Delta had a low median PCR cycle threshold value (a proxy for high virus load). This value was similar to the median cycle threshold value for unvaccinated patients with COVID-19 caused by Delta variants, suggesting that fully vaccinated individuals can transmit SARS-CoV-2 to others. Patients infected with Alpha and Delta variants had several significant differences. The integrated analysis indicates that vaccines used in the United States are highly effective in decreasing severe COVID-19, hospitalizations, and deaths.
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U2 - 10.1016/j.ajpath.2021.10.019
DO - 10.1016/j.ajpath.2021.10.019
M3 - Article
C2 - 34774517
AN - SCOPUS:85124232692
VL - 192
SP - 320
EP - 331
JO - American Journal of Pathology
JF - American Journal of Pathology
SN - 0002-9440
IS - 2
ER -