BA.5 sub-lineages associated with higher severity of COVID-19 infection: A cross-sectional study in Indonesia.

Objectives: We aimed to compare the clinical severity and outcome among laboratory-confirmed Omicron variant cases admitted between January and December 2022.

Methods: This is a cross-sectional study conducted in Hasan Sadikin General Hospital between January and December 2022. We enrolled patients aged ≥18 years with laboratory-confirmed Omicron infection. Data were collected from clinical records and a whole genome sequencing database. We compared the risk of severe symptoms and mortality using a logistic regression analysis adjusted for sex, age, comorbidities, and vaccination status.

Results: We enrolled 255 patients and the main sub-lineages were BA.1 (16.1%), BA.2 (11.4%), BA.5 (35.7%), XBB (22.7%), and BQ.1 (14.1%). Compared with BA.1/BA.2, BA.5 sub-lineages were associated with severe symptoms (adjusted odds ratio of 2.9, 95% confidence interval 1.1-8.2, <0.05). The highest risk of severe symptoms and mortality was linked with a high number of comorbidities (adjusted odds ratio of 7.8, 95% confidence interval 1.7-22.4, <0.05). Booster vaccination was protective of severity and mortality.

Conclusions: Disease severity was associated with BA.5 sub-lineages and multiple comorbidities. Good management is particularly important for people with comorbidities. Furthermore, booster vaccination is also required to reduce severity and mortality.