3.0 Paediatric Clinical Presentation: Omicron Sub-variants (2024-2025 Season)
While new SARS-CoV-2 variants continue to emerge, their clinical profile largely aligns with a general upper respiratory tract infection (URTI), a reality that creates significant diagnostic challenges for clinicians differentiating COVID-19 from other seasonal viruses. For the 2024-2025 season, the Omicron lineages present with a familiar constellation of symptoms.
Commonly reported symptoms include:
- Nasal congestion or rhinorrhea
- Cough
- Fatigue or weakness
- Fever or chills
- Headache and myalgia
- Sore throat
- Sneezing
- Dyspnea
- Gastrointestinal symptoms (diarrhea, nausea/vomiting)
- Occasional loss of taste or smell
3.1 Characterizing the Nimbus (NB.1.8.1) Variant
The Nimbus variant has distinguished itself with a particularly notable hallmark symptom: an intensely painful sore throat, described colloquially as a “razor-like sore throat” (jilet gibi boğaz ağrısı). This specific sign, when present, can be a strong clinical indicator for this lineage. The Nimbus variant is reportedly responsible for approximately 43% of cases in the United States.
The following table delineates the defining clinical features of the Nimbus variant from its other common associated symptoms, as reported by authorities such as the UK’s National Health Service.
| Defining Clinical Signs | Other Associated Symptoms |
| Intense, sharp sore throat | Fatigue |
| Cervical lymphadenopathy | Fever |
| Myalgia | |
| Rhinorrhea | |
| Headache | |
| Sneezing | |
| Nausea, vomiting, and diarrhea |
3.2 Profile of the Stratus (XFG) Variant
The Stratus (XFG) variant is another sub-lineage that is increasing in prevalence, particularly in Europe and India. Its clinical profile does not appear to deviate significantly from other Omicron lineages. Symptoms associated with Stratus are reported to include chills, dyspnea, sore throat, fatigue, headache, myalgia, nausea/vomiting, diarrhea, hoarseness, and occasional loss of taste or smell.
The considerable symptomatic overlap between these new sub-variants and other common respiratory pathogens creates a significant diagnostic dilemma for the treating clinician.