Estimates of prevalence of anti-SARS-CoV-2 antibodies among blood donors in South Africa in March 2022

Bingham, Jeremy; Cable, Russel; Coleman, Charl; Glatt, Tanya Nadia; Grebe, Eduard; Mhlanga, Laurette; Nyano, Cynthia; Pieterson, Nadia; Swanevelder, Ronél; Swarts, Avril; Sykes, Wendy; Berg, Karin van den; Vermeulen, Marion; Welte, Alex

doi:10.21203/rs.3.rs-1687679/v2

Cited by 19 publications

(17 citation statements)

References 2 publications

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“…Nonetheless, these example estimates (Table S4) are consistent with reported serology measures [4 th column vs. e.g. ∼90% seropositive in March 2022 after the Omicron BA.1 wave reported in Bingham et al 2022 (8)] and reinfection rates reported elsewhere [5 th and 6 th columns vs. e.g., reported much higher reinfection rate during the Omicron wave in Pulliam et al (9)].…”

Section: A Proposed Approach To Compute the Reinfection Rates Using M...supporting

confidence: 86%

COVID-19 pandemic dynamics in South Africa and epidemiological characteristics of three variants of concern (Beta, Delta, and Omicron)

Yang¹,

Shaman

2021

Preprint

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Within days of first detection, Omicron SARS-CoV-2 variant case numbers grew exponentially and spread globally. To better understand variant epidemiological characteristics, we utilize a model-inference system to reconstruct SARS-CoV-2 transmission dynamics in South Africa and decompose novel variant transmissibility and immune erosion. Accounting for under-detection of infection, infection seasonality, nonpharmaceutical interventions, and vaccination, we estimate that the majority of South Africans had been infected by SARS-CoV-2 before the Omicron wave. Based on findings for Gauteng province, Omicron is estimated 100.3% (95% CI: 74.8 - 140.4%) more transmissible than the ancestral SARS-CoV-2 and 36.5% (95% CI: 20.9 - 60.1%) more transmissible than Delta; in addition, Omicron erodes 63.7% (95% CI: 52.9 - 73.9%) of the population immunity, accumulated from prior infections and vaccination, in Gauteng.

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Section: A Proposed Approach To Compute the Reinfection Rates Using M...supporting

confidence: 86%

COVID-19 pandemic dynamics in South Africa and epidemiological characteristics of three variants of concern (Beta, Delta, and Omicron)

Yang¹,

Shaman

2021

Preprint

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“…The reduced mortality in the Omicron BA.4/BA.5 wave was more specifically presumed to be related to the high prevalence of humoral and cell-mediated immunity in South Africa. Studies of humoral immunity reported SARS-CoV-2 antibody sero-prevalence estimates of 71% (26) and 73% (3) before the Omicron BA.1/BA.2 wave, while estimates after the Omicron BA.1/BA.2 wave but just before the Omicron BA.4/BA.5 wave were 97% (27) and 91% (28). The latter serosurvey indicated that 61% of individuals had serological evidence of SARS-CoV-2 infection during the Omicron BA.1/BA.2 wave in South Africa (28).…”

Section: Discussionmentioning

confidence: 99%

Trends in Cases, Hospitalisation and Mortality Related to the Omicron BA.4/BA.5 Sub-Variants in South Africa

Jassat

Karim

Ozougwu

et al. 2022

Preprint

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Introduction: The Omicron BA.1/BA.2 wave in South Africa had lower hospitalisation and mortality than previous SARS-CoV-2 variants and was followed by an Omicron BA.4/BA.5 wave. This study compared admission incidence risk across waves, and the risk of mortality in the Omicron BA.4/BA.5 wave, to the Omicron BA.1/BA.2 and Delta waves. Methods: Data from South Africa's national hospital surveillance system, SARS-CoV-2 case linelist and Electronic Vaccine Data System were linked and analysed. Wave periods were defined when the country passed a weekly incidence of 30 cases/100,000 people. Mortality rates in the Delta, Omicron BA.1/BA.2 and Omicron BA.4/BA.5 wave periods were compared by post-imputation random effect multivariable logistic regression models. Results: In-hospital deaths declined 6-fold from 37,537 in the Delta wave to 6,074 in the Omicron BA.1/BA.2 wave and a further 7-fold to 837 in the Omicron BA.4/BA.5 wave. The case fatality ratio (CFR) was 25.9% (N=144,798), 10.9% (N=55,966) and 7.1% (N=11,860) in the Delta, Omicron BA.1/BA.2, and Omicron BA.4/BA.5 waves respectively. After adjusting for age, sex, race, comorbidities, health sector and province, compared to the Omicron BA.4/BA.5 wave, patients had higher risk of mortality in the Omicron BA.1/BA.2 wave (adjusted odds ratio [aOR] 1.43; 95% confidence interval [CI] 1.32-1.56) and Delta (aOR 3.22; 95% CI 2.98-3.49) wave. Being partially vaccinated (aOR 0.89, CI 0.86-0.93), fully vaccinated (aOR 0.63, CI 0.60-0.66) and boosted (aOR 0.31, CI 0.24-0.41); and prior laboratory-confirmed infection (aOR 0.38, CI 0.35-0.42) were associated with reduced risks of mortality. Conclusion: Overall, admission incidence risk and in-hospital mortality, which had increased progressively in South Africa's first three waves, decreased in the fourth Omicron BA.1/BA.2 wave and declined even further in the fifth Omicron BA.4/BA.5 wave. Mortality risk was lower in those with natural infection and vaccination, declining further as the number of vaccine doses increased.

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“…This is consistent with ongoing affinity maturation of responses after second antigenic exposures (28). In South Africa, where >95% of people are now estimated to be seropositive, this scenario of hybrid immunity is likely very common (17,29). However, even in the context of these high titer responses, BA.4 shows reduced sensitivity to neutralization compared to other VOCs, perhaps accounting for ongoing community transmission.…”

Section: Discussionmentioning

confidence: 99%

Fc effector activity and neutralization against SARS-CoV-2 BA.4 is compromised in convalescent sera, regardless of the infecting variant

Richardson

Kgagudi

Manamela

et al. 2022

Preprint

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The SARS-CoV-2 Omicron BA.1 variant, which exhibits high level neutralization resistance, has since evolved into several sub-lineages including BA.4 and BA.5, which have dominated the fifth wave of infection in South Africa. Here we assessed the sensitivity of BA.4 to neutralization and antibody dependent cellular cytotoxicity (ADCC) in convalescent donors infected with four previous variants of SARS-CoV-2, as well as in post-vaccination breakthrough infections (BTIs) caused by Delta or BA.1. We confirm that BA.4 shows high level resistance to neutralization, regardless of the infecting variant. However, breakthrough infections, which trigger potent neutralization, retained activity against BA.4, albeit at reduced titers. Fold reduction of neutralization in BTIs was lower than that seen in unvaccinated convalescent donors, suggesting maturation of neutralizing responses to become more resilient against VOCs in hybrid immunity. BA.4 sensitivity to ADCC was reduced but remained detectable in both convalescent donors and in BTIs. Overall, the high neutralization resistance of BA.4, even to antibodies from BA.1 infections, provides an immunological mechanism for the rapid spread of BA.4 immediately after a BA.1-dominated wave. Furthermore, although ADCC activity against BA.4 was reduced, residual activity may nonetheless contribute to the protection from disease.

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Estimates of prevalence of anti-SARS-CoV-2 antibodies among blood donors in South Africa in March 2022

Cited by 19 publications

References 2 publications

COVID-19 pandemic dynamics in South Africa and epidemiological characteristics of three variants of concern (Beta, Delta, and Omicron)

COVID-19 pandemic dynamics in South Africa and epidemiological characteristics of three variants of concern (Beta, Delta, and Omicron)

Trends in Cases, Hospitalisation and Mortality Related to the Omicron BA.4/BA.5 Sub-Variants in South Africa

Fc effector activity and neutralization against SARS-CoV-2 BA.4 is compromised in convalescent sera, regardless of the infecting variant

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