SARS-CoV-2 variants 2024
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SARS-CoV-2 Variant Trends in 2024: Omicron Lineages and Global Surveillance
Omicron Variant Evolution and Dominant Lineages in 2024
Throughout 2023 and into 2024, the global landscape of SARS-CoV-2 has been dominated by Omicron and its rapidly evolving lineages. In China’s Henan Province, BA.5.2 was the main variant until April 2023, after which XBB took over. By January 2024, BA.2.86 became the predominant variant, with XBB and BA.2.86 both showing lower severity and fewer severe or fatal cases compared to earlier variants. Most infections were mild, and severe outcomes were more common in older adults, males, and with certain variants like BA.5.2, but less so with XBB and BA.2.86 .
In the United States, Omicron descendants XBB and JN.1 were the primary circulating lineages from May 2023 to September 2024. XBB descendants such as EG.5, FL.1.5.1, HV.1, and HK.3 rose in prevalence through 2023. In winter 2023, JN.1 emerged and quickly became dominant, representing a significant genetic shift from previous XBB lineages. New JN.1 descendants, including KQ.1, KP.2, KP.3, and LB.1, continued to appear and circulate through mid-2024. Surges in COVID-19 cases were observed during the transitions between these dominant lineages .
Immune Evasion, Disease Severity, and Vaccine Effectiveness
Omicron and its subvariants have shown significant immune escape, which has challenged both natural and vaccine-induced immunity. This immune evasion has led to breakthrough infections in vaccinated and previously infected individuals, reducing the effectiveness of existing vaccines and immunotherapies Song2025C.2024Dhama2022. However, despite increased transmissibility and immune escape, the overall severity of disease caused by recent Omicron lineages, including XBB, BA.2.86, and JN.1, has generally been lower, with fewer severe and fatal cases reported Song2025C.2024.
Ongoing Challenges and Strategies for Control
The continuous emergence of new SARS-CoV-2 variants, especially those with immune escape capabilities, poses ongoing challenges for public health. These challenges include maintaining vaccine effectiveness, updating vaccine formulations, and ensuring effective surveillance to detect and respond to new variants quickly C.2024Dhama2022Edwin2023. Nanotechnology-based strategies, such as mRNA vaccines, have played a crucial role in the pandemic response, but the rapid evolution of the virus means that new approaches and updated vaccines will be needed to keep pace with emerging variants .
Importance of Genomic Surveillance
Both global and regional studies emphasize the critical importance of ongoing genomic surveillance. Monitoring the genetic changes in SARS-CoV-2 helps guide public health decisions, informs vaccine updates, and supports the development of new medical countermeasures. Continuous surveillance is essential to detect new variants early and to adapt strategies for prevention and control Song2025C.2024Dhama2022.
Conclusion
In 2024, SARS-CoV-2 continues to evolve, with Omicron subvariants such as XBB, BA.2.86, and JN.1 dominating in different regions. These variants are characterized by increased transmissibility and immune escape but generally cause less severe disease. Ongoing genomic surveillance and the rapid adaptation of vaccines and therapeutics remain essential to managing the pandemic and mitigating the impact of future SARS-CoV-2 variants.
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