01 December 2025 : Editorial
Editorial: COVID-19 Six Years on and Endemic Omicron Variants of SARS-CoV-2 Under Monitoring Now Include NB.1.8.1 (Nimbus) and XFG (Stratus)
Dinah V. Parums
E 1*
DOI: 10.12659/MSM.952217
Med Sci Monit 2025; 31:e952217
Table 1 Six years on. Some key COVID-19 timelines and events from December 2019 to November 2025 and the Omicron variants of SARS-CoV-2.
| Date | Key event |
|---|---|
| December 12 2019 | Patients in Hubei Province, China, reported symptoms of atypical pneumonia, unresponsive to treatment []1 |
| December 31 2019 | The World Health Organization (WHO) in China received reports of atypical pneumonia cases in Wuhan []1 |
| January 10 2020 | The WHO identifies the 2019 novel coronavirus (2019-nCoV) as the cause of cases of atypical pneumonia []17 |
| January 11 2020 | The WHO receives the novel coronavirus’s genetic sequence. China reports the first death from SARS-CoV-2 infection []1 |
| January 13 2020 | The first confirmed cases outside China were reported, and human-to-human transmission is suspected []3 |
| January 30 2020 | The WHO first declared that COVID-19 was a public health emergency of international concern (PHEIC) []2 |
| February 11 2020 | The WHO announces the official name for the disease as Coronavirus Disease 2019 (COVID-19) []3 |
| March 11 2020 | More than 118,000 reported cases in 143 countries and 4,291 deaths were reported, which resulted in a declaration of a COVID-19 pandemic by the WHO []3 |
| May 8 2020 | The US Food and Drug Administration (FDA) authorized the first COVID-19 test that used saliva samples []3 |
| September 22 2020 | The reported global mortality from COVID-19 exceeded 1 million within the first 10 months of the pandemic []3 |
| May 31 2021 | The Virus Evolution Working Group of the World Health Organization (WHO) recommended the revised naming of SARS-CoV-2 variants of concern (VOC) and variants of interest (VOI) []6 |
| November 26 2021 | The Omicron variant, B.1.1.529, of SARS-CoV-2 was included in the WHO list of variants of concern (VOC) and became the dominant variant in many countries []7 |
| January 21 2022 | The WHO published its recommendations for priority actions in response to the Omicron variant, B.1.1.529, of SARS-CoV-2, and the Omicron variant (and its five lineages, BA.1, BA.2, BA.3, BA.4, and BA.5) became the predominant cause of COVID-19 worldwide [,]7 |
| June 7 2022 | The WHO added a new category to its SARS-CoV-2 variant tracking system, the VOC Lineages Under Monitoring (VOC-LUM), to inform global health authorities of the VOC lineages and sublineages that may require priority attention and monitoring []8 |
| January 12 2023 | The Omicron XBB.1.5 (Kraken) subvariant (a sublineage of the XBB variant) caused 49.1% of cases of COVID-19 in the US []9 |
| May 5 2023 | The Director-General of the World Health Organization (WHO) advised that COVID-19 was now an established and ongoing health issue and no longer a PHEIC due to decreasing mortality, declining hospital admissions and intensive care unit (ICU) admissions, and increasing population immunity to SARS-CoV-2 []2 |
| August 8 2023 | The WHO identified EG.5 (Eris) as a variant under monitoring (VUM) and a variant of interest (VOI) []10 |
| December 18 2023 | Mutations in the SARS-CoV-2 spike protein occurred rapidly, with the Omicron variant (B.1.1.529) and its subvariants, Kraken (XBB.1.5), Eris (EG.5), and Pirola (BA.2.86) being successively dominant in the previous two years. Also, the WHO designated JN.1 as a separate variant of interest (VOI) from the parent lineage, BA.2.86, due to its rapid spread []11 |
| June 25 2025 | The WHO reported a risk evaluation for two SARS-CoV-2 variants under monitoring (VUM), NB.1.8.1 (Nimbus) and XFG (Stratus) [,]14 |
| From mid-2025 | Increasing numbers of COVID-19 cases were reported in 2025. Towards the end of 2025, genomic analysis of the infecting SARS-CoV-2 virus identified the most common circulating variants to be XFG (Stratus), which is dominant in Europe and the Americas, and NB.1.8.1 (Nimbus), which is dominant in the Western Pacific region []4 |
| November 2 2025 | The total number of COVID-19 cases reported to the WHO in the past six years was []13 |