Update on the omicron sub-variants BA.4 and BA.5.

Area of Science:

• Virology
• Epidemiology
• Public Health

Background:

• Global relaxation of public health measures, including mask mandates for outdoor activities, is occurring due to declining coronavirus disease 2019 (COVID-19) cases.
• Emergence of new Omicron sub-variants, BA.4 and BA.5, is linked to a rise in COVID-19 cases in South Africa, the US, and Europe, with spread now observed in Asia.

Purpose of the Study:

• To review scientific considerations regarding the new Omicron BA.4 and BA.5 sub-variants.
• To analyze the characteristics of these sub-variants, including their transmissibility and immune evasion capabilities.

Main Methods:

• Review of scientific literature and epidemiological data.
• Analysis of variant evolution from the Omicron lineage.
• Assessment of clinical severity data associated with BA.4 and BA.5 infections.

Main Results:

• Omicron BA.4 and BA.5 sub-variants exhibit increased contagiousness compared to previous strains.
• These sub-variants demonstrate an ability to circumvent immunity acquired from prior infection or vaccination.
• Preliminary data suggests a potentially reduced clinical severity associated with BA.4 and BA.5 infections.

Conclusions:

• The emergence of Omicron BA.4 and BA.5 necessitates ongoing scientific monitoring and public health vigilance.
• Despite increased transmissibility and immune evasion, the reduced clinical severity warrants further investigation.
• Understanding these variants is crucial for adapting public health strategies in the ongoing COVID-19 pandemic.