Clinical severity of SARS-CoV-2 Omicron BA.4 and BA.5 lineages compared to BA.1 and Delta in South Africa

• Published in: Nature communications 2022-10, Vol.13 (1), p.5860-8, Article 5860
• Main Authors: Wolter, Nicole, Jassat, Waasila, Walaza, Sibongile, Welch, Richard, Moultrie, Harry, Groome, Michelle J., Amoako, Daniel Gyamfi, Everatt, Josie, Bhiman, Jinal N., Scheepers, Cathrine, Tebeila, Naume, Chiwandire, Nicola, du Plessis, Mignon, Govender, Nevashan, Ismail, Arshad, Glass, Allison, Mlisana, Koleka, Stevens, Wendy, Treurnicht, Florette K., Subramoney, Kathleen, Makatini, Zinhle, Hsiao, Nei-yuan, Parboosing, Raveen, Wadula, Jeannette, Hussey, Hannah, Davies, Mary-Ann, Boulle, Andrew, von Gottberg, Anne, Cohen, Cheryl
• Format: Article
• Language: English
• Subjects: 631/326/596/4130; 692/308/174; 692/499; 692/699/255/2514; Coronaviruses; COVID-19; COVID-19 - epidemiology; Health risks; Hospitalization; Humanities and Social Sciences; Humans; Infections; Laboratory tests; multidisciplinary; Risk; SARS-CoV-2 - genetics; Science; Science (multidisciplinary); Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; South Africa - epidemiology
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-33614-0

Omicron lineages BA.4 and BA.5 drove a fifth wave of COVID-19 cases in South Africa. Here, we use the presence/absence of the S-gene target as a proxy for SARS-CoV-2 variant/lineage for infections diagnosed using the TaqPath PCR assay between 1 October 2021 and 26 April 2022. We link national COVID-19 individual-level data including case, laboratory test and hospitalisation data. We assess severity using multivariable logistic regression comparing the risk of hospitalisation and risk of severe disease, once hospitalised, for Delta, BA.1, BA.2 and BA.4/BA.5 infections. After controlling for factors associated with hospitalisation and severe outcome respectively, BA.4/BA.5-infected individuals had a similar odds of hospitalisation (aOR 1.24, 95% CI 0.98–1.55) and severe outcome (aOR 0.72, 95% CI 0.41–1.26) compared to BA.1-infected individuals. Newly emerged Omicron lineages BA.4/BA.5 showed similar severity to the BA.1 lineage and continued to show reduced clinical severity compared to the Delta variant. South Africa experienced a resurgence in COVID-19 in 2022 driven by Omicron subvariants BA.4 and BA.5. Here, the authors investigate the severity of infections caused by these subvariants, and find no difference in the risk of severe outcomes when compared to Omicron BA.1, whilst all Omicron subvariants were less severe than Delta.