Association of SARS-CoV-2 viral load distributions with individual demographics and suspected variant type: results from the Liverpool community testing pilot, England, 6 November 2020 to 8 September 2021.
Euro Surveill
; 28(4)2023 01.
Article
in English
| MEDLINE | ID: covidwho-2215129
ABSTRACT
BackgroundThe PCR quantification cycle (Cq) is a proxy measure of the viral load of a SARS-CoV-2-infected individual.AimTo investigate if Cq values vary according to different population characteristics, in particular demographic ones, and within the COVID-19 pandemic context, notably the SARS-CoV-2 type/variant individuals get infected with.MethodsWe considered all positive PCR results from Cheshire and Merseyside, England, between 6 November 2020 and 8 September 2021. Cq distributions were inspected with Kernel density estimates. Multivariable quantile regression models assessed associations between people's features and Cq.ResultsWe report Cq values for 188,821 SARS-CoV-2 positive individuals. Median Cqs increased with decreasing age for suspected wild-type virus and Alpha variant infections, but less so, if not, for Delta. For example, compared to 30-39-year-olds (median age group), 5-11-year-olds exhibited 1.8 (95% CI 1.5 to 2.1), 2.2 (95% CI 1.8 to 2.6) and 0.8 (95% CI 0.6 to 0.9) higher median Cqs for suspected wild-type, Alpha and Delta positives, respectively, in multivariable analysis. 12-18-year-olds also had higher Cqs for wild-type and Alpha positives, however, not for Delta. Overall, in univariable analysis, suspected Delta positives reported 2.8 lower median Cqs than wild-type positives (95% CI 2.7 to 2.8; p < 0.001). Suspected Alpha positives had 1.5 (95% CI 1.4 to 1.5; p < 0.001) lower median Cqs than wild type.ConclusionsWild-type- or Alpha-infected school-aged children (5-11-year-olds) might transmit less than adults (> 18 years old), but have greater mixing exposures. Smaller differences in viral loads with age occurred in suspected Delta infections. Suspected-Alpha- or Delta-infections involved higher viral loads than wild type, suggesting increased transmission risk. COVID-19 control strategies should consider age and dominant variant.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
SARS-CoV-2
/
COVID-19
Type of study:
Observational study
/
Prognostic study
Topics:
Variants
Limits:
Adolescent
/
Adult
/
Child
/
Humans
Country/Region as subject:
Europa
Language:
English
Journal subject:
Communicable Diseases
Year:
2023
Document Type:
Article
Affiliation country:
1560-7917.ES.2023.28.4.2200129
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