tetano
Editor, Senior Moderator
BMC Infect Dis
. 2024 Mar 21;24(1):336.
doi: 10.1186/s12879-024-09209-z. Characteristics of infections with ancestral, Beta and Delta variants of SARS-CoV-2 in the PHIRST-C community cohort study, South Africa, 2020-2021
Cheryl Cohen[SUP] 1 2 [/SUP], Jackie Kleynhans[SUP] 3 4 [/SUP], Anne von Gottberg[SUP] 3 5 [/SUP], Meredith L McMorrow[SUP] 6 [/SUP], Nicole Wolter[SUP] 3 5 [/SUP], Jinal N Bhiman[SUP] 3 5 [/SUP], Jocelyn Moyes[SUP] 3 4 [/SUP], Mignon du Plessis[SUP] 3 5 [/SUP], Maimuna Carrim[SUP] 3 5 [/SUP], Amelia Buys[SUP] 3 [/SUP], Neil A Martinson[SUP] 7 8 9 [/SUP], Kathleen Kahn[SUP] 10 [/SUP], Stephen Tollman[SUP] 10 [/SUP], Limakatso Lebina[SUP] 7 11 [/SUP], Floidy Wafawanaka[SUP] 10 [/SUP], Jacques du Toit[SUP] 10 [/SUP], Francesc Xavier Gómez-Olivé[SUP] 10 [/SUP], Fatimah S Dawood[SUP] 6 [/SUP], Thulisa Mkhencele[SUP] 3 [/SUP]; PHIRST group; Stefano Tempia[SUP] 3 4 6 [/SUP]
Affiliations
Background: Data on the characteristics of individuals with mild and asymptomatic infections with different SARS-CoV-2 variants are limited. We therefore compared the characteristics of individuals infected with ancestral, Beta and Delta SARS-CoV-2 variants in South Africa.
Methods: We conducted a prospective cohort study in a rural and an urban site during July 2020-August 2021. Mid-turbinate nasal swabs were collected twice-weekly from household members irrespective of symptoms and tested for SARS-CoV-2 using real-time reverse transcription polymerase chain reaction (rRT-PCR). Differences in demographic and clinical characteristics, shedding and cycle threshold (Ct) value of infection episodes by variant were evaluated using multinomial regression. Overall and age-specific incidence rates of infection were compared by variant.
Results: We included 1200 individuals from 222 households and 648 rRT-PCR-confirmed infection episodes (66, 10% ancestral, 260, 40% Beta, 322, 50% Delta). Symptomatic proportion was similar for ancestral (7, 11%), Beta (44, 17%), and Delta (46, 14%) infections (p=0.4). After accounting for previous infection, peak incidence shifted to younger age groups in successive waves (40-59 years ancestral, 19-39 years Beta, 13-18 years Delta). On multivariable analysis, compared to ancestral, Beta infection was more common in individuals aged 5-12 years (vs 19-39)(adjusted odds ratio (aOR) 2.6, 95% confidence interval (CI)1.1-6.6) and PCR cycle threshold (Ct) value <30 (vs >35)(aOR 3.2, 95%CI 1.3-7.9), while Delta was more common in individuals aged <5 (aOR 6.7, 95%CI1.4-31.2) and 5-12 years (aOR 6.6 95%CI2.6-16.7)(vs 19-39) and Ct value <30 (aOR 4.5, 95%CI 1.3-15.5) and 30-35 (aOR 6.0, 95%CI 2.3-15.7)(vs >35).
Conclusions: Consecutive SARS-CoV-2 waves with Beta and Delta variants were associated with a shift to younger individuals. Beta and Delta infections were associated with higher peak viral loads, potentially increasing infectiousness.
Keywords: Cohort study; Epidemiology; SARS-CoV-2; South Africa.
. 2024 Mar 21;24(1):336.
doi: 10.1186/s12879-024-09209-z. Characteristics of infections with ancestral, Beta and Delta variants of SARS-CoV-2 in the PHIRST-C community cohort study, South Africa, 2020-2021
Cheryl Cohen[SUP] 1 2 [/SUP], Jackie Kleynhans[SUP] 3 4 [/SUP], Anne von Gottberg[SUP] 3 5 [/SUP], Meredith L McMorrow[SUP] 6 [/SUP], Nicole Wolter[SUP] 3 5 [/SUP], Jinal N Bhiman[SUP] 3 5 [/SUP], Jocelyn Moyes[SUP] 3 4 [/SUP], Mignon du Plessis[SUP] 3 5 [/SUP], Maimuna Carrim[SUP] 3 5 [/SUP], Amelia Buys[SUP] 3 [/SUP], Neil A Martinson[SUP] 7 8 9 [/SUP], Kathleen Kahn[SUP] 10 [/SUP], Stephen Tollman[SUP] 10 [/SUP], Limakatso Lebina[SUP] 7 11 [/SUP], Floidy Wafawanaka[SUP] 10 [/SUP], Jacques du Toit[SUP] 10 [/SUP], Francesc Xavier Gómez-Olivé[SUP] 10 [/SUP], Fatimah S Dawood[SUP] 6 [/SUP], Thulisa Mkhencele[SUP] 3 [/SUP]; PHIRST group; Stefano Tempia[SUP] 3 4 6 [/SUP]
Affiliations
- PMID: 38515050
- PMCID: PMC10956206
- DOI: 10.1186/s12879-024-09209-z
Background: Data on the characteristics of individuals with mild and asymptomatic infections with different SARS-CoV-2 variants are limited. We therefore compared the characteristics of individuals infected with ancestral, Beta and Delta SARS-CoV-2 variants in South Africa.
Methods: We conducted a prospective cohort study in a rural and an urban site during July 2020-August 2021. Mid-turbinate nasal swabs were collected twice-weekly from household members irrespective of symptoms and tested for SARS-CoV-2 using real-time reverse transcription polymerase chain reaction (rRT-PCR). Differences in demographic and clinical characteristics, shedding and cycle threshold (Ct) value of infection episodes by variant were evaluated using multinomial regression. Overall and age-specific incidence rates of infection were compared by variant.
Results: We included 1200 individuals from 222 households and 648 rRT-PCR-confirmed infection episodes (66, 10% ancestral, 260, 40% Beta, 322, 50% Delta). Symptomatic proportion was similar for ancestral (7, 11%), Beta (44, 17%), and Delta (46, 14%) infections (p=0.4). After accounting for previous infection, peak incidence shifted to younger age groups in successive waves (40-59 years ancestral, 19-39 years Beta, 13-18 years Delta). On multivariable analysis, compared to ancestral, Beta infection was more common in individuals aged 5-12 years (vs 19-39)(adjusted odds ratio (aOR) 2.6, 95% confidence interval (CI)1.1-6.6) and PCR cycle threshold (Ct) value <30 (vs >35)(aOR 3.2, 95%CI 1.3-7.9), while Delta was more common in individuals aged <5 (aOR 6.7, 95%CI1.4-31.2) and 5-12 years (aOR 6.6 95%CI2.6-16.7)(vs 19-39) and Ct value <30 (aOR 4.5, 95%CI 1.3-15.5) and 30-35 (aOR 6.0, 95%CI 2.3-15.7)(vs >35).
Conclusions: Consecutive SARS-CoV-2 waves with Beta and Delta variants were associated with a shift to younger individuals. Beta and Delta infections were associated with higher peak viral loads, potentially increasing infectiousness.
Keywords: Cohort study; Epidemiology; SARS-CoV-2; South Africa.