Reinfection rate and disease severity of the BA.5 Omicron SARS-CoV-2 lineage compared to previously circulating variants of concern in the Canary Islands (Spain)

Abstract

The emergence of the Omicron SARS-CoV-2 variant of concern has changed the COVID-19 scenario as this variant is characterized by high transmissibility and immune evasion ability. To evaluate the impact of this variant on the Canary Islands (Spain) population, we determined the reinfection rates and disease severity associated with the Omicron sublineages and the previously circulating variants of concern. We performed a retrospective observational study on 21,745 SARS-CoV-2 viral genomes collected from December 2020 to July 2022 in the Canary Islands (Spain). We compared the reinfection rates between lineages using pairwise proportion and Fisher’s exact tests. To assess disease severity, we studied the association of Alpha, Delta, BA.1, BA.2, BA.5, and other risk factors on 28-day hospital mortality using logistic regression and Cox proportional hazard models. We observed 127 bona fide reinfection cases throughout the study period. We found that BA.5 had the highest reinfection rate compared to other lineages (vs. Delta p = 2.89 × 10 −25 ; vs. BA.1 p = 5.17 × 10 −11 ; vs. BA.2 p = 0.002). Among the 1,094 hospitalized patients, multivariate logistic regression showed that Alpha (Odds Ratio [OR] = 0.45, 95% Confidence Interval [CI] = 0.23-0.87, p = 0.02), BA.2 (OR = 0.38, 95% CI = 0.22-0.63, p = 1.91 × 10 −4 ), and BA.5 (OR = .30, 95% CI = 0.16-0.55, p = 1.05 × 10 −4 ) had lower 28-day hospital mortality compared to Delta. These results were confirmed by using Cox proportional hazard models. Omicron lineages, and in particular BA.5, were associated with higher reinfection rates and lower disease severity (28-day hospital mortality) than previously circulating variants of concern.

How does the SARS-CoV-2 reinfection rate change over time? The global evidence from systematic review and meta-analysis

“…This study showed that the total reinfection rate varies among different reinfected variants, with the Omicron variant having a significantly higher reinfection rate than other variants. This is consistent with the research results of Ciuffreda [ 30 ], Cohen [ 31 ], and Pulliam JRC et al [ 32 ]. The Omicron variant has a lower protective effect on reinfection compared to other variants, resulting in a significantly higher reinfection rate of the Omicron variant [ 33 ].…”

Comparing COVID-19 severity in patients hospitalized for community-associated Delta, BA.1 and BA.4/5 variant infection

“…The lower severity of the BA.4/5 variant compared to the BA.1 and the Delta variants was confirmed in the present study. Studies published on the severity of BA.4/5 found no difference, increase or decrease compared to the earlier Omicron variants ( 3 , 24 , 26 , 33 , 35 , 36 ). However, these conflicting results merit further research as do studies regarding quality of life indicators and their correlation with the severity of the SARS-CoV-2 infection ( 37 ).…”

Neutralizing antibody responses and cellular responses against SARS-CoV-2 Omicron subvariant BA.5 after mRNA SARS-CoV-2 vaccination in kidney transplant recipients

“…Although the current bivalent Omicron-containing booster vaccine produced increased anti-SARS-CoV-2 spike protein IgG and neutralizing antibody titers, these effects were lower in KTXRs than in healthy controls. Therefore, although the severity of the Omicron variants is less than that of the previous lineages 34,35 , KTXRs might be more susceptible to Omicron BA.5 and develop more severe disease.…”