COVID-19 XBB Variant: Symptoms and Impact in the USA
Introduction
COVID-19 continues to evolve, with new variants emerging that challenge global health efforts. In 2023, the XBB variant, a sublineage of Omicron, has become a prominent concern, particularly in the United States. As this new variant spreads, understanding its symptoms and impact becomes crucial in mitigating its effects.
The XBB Variant: An Overview

The XBB variant, also known as the XBB.1.5 or “Kraken” variant, is a recombinant strain. It was first identified as a fusion of two Omicron subvariants, BA.2.10.1 and BA.2.75. Recombinant strains arise when two different variants of the virus infect the same host and swap genetic material, leading to a new combination of mutations. This characteristic gives the XBB variant unique properties in terms of transmissibility, immune evasion, and symptomatology.
Symptoms of the XBB Variant

While the symptoms of COVID-19 have ranged broadly since the start of the pandemic, the XBB variant has introduced some subtle shifts in symptom presentation. Like previous variants, the XBB strain mainly affects the respiratory system. However, it has been noted for showing a blend of symptoms associated with both the original SARS-CoV-2 virus and the Omicron variants. Here are some of the commonly reported symptoms associated with the XBB variant:
1. Sore Throat: One of the most reported symptoms of the XBB variant is a sore throat. Patients often describe it as persistent and more intense compared to previous variants.
2. Nasal Congestion: Unlike the original COVID-19 strain, which primarily led to a dry cough and fever, the XBB variant frequently presents with nasal congestion and a runny nose, resembling symptoms of the common cold.
3. Cough: A dry or wet cough is still prevalent among XBB infections. However, some patients report a milder cough compared to earlier strains of the virus.
4. Headache: Headaches are a common complaint, often accompanied by sinus pressure and discomfort, which can be mistaken for seasonal allergies or a sinus infection.
5. Fatigue: Severe fatigue and general malaise continue to be reported by those infected with the XBB variant. This symptom can last for several weeks even after other symptoms have resolved.
6. Fever: Although not as common as in earlier COVID-19 variants, fever is still occasionally observed. When present, it tends to be low-grade.
7. Muscle Aches and Joint Pain: Similar to previous strains, individuals may experience generalized muscle aches and joint pain.
8. Gastrointestinal Symptoms: Nausea, diarrhea, and stomach cramps have been increasingly reported with the XBB variant, suggesting that this strain may have a broader impact on the body.
9. Loss of Smell or Taste: While less frequent compared to the original strain, some individuals with the XBB variant still report a temporary loss of smell or taste.
Differences from Previous Variants

One notable difference with the XBB variant is the increased incidence of upper respiratory symptoms such as nasal congestion and sore throat. Early strains of COVID-19 primarily affected the lower respiratory tract, leading to symptoms like a dry cough and shortness of breath. The shift to upper respiratory symptoms in the XBB variant may explain why it can be mistaken for a common cold or seasonal flu, potentially leading to underdiagnosis or delayed isolation.
Severity and Hospitalization Rates
Preliminary data suggest that the XBB variant, like other Omicron sublineages, may cause less severe illness than previous variants, such as Delta. The overall hospitalization rate appears to be lower, and the cases that do require hospital care often involve individuals with underlying health conditions or those who are immunocompromised.
However, due to its high transmissibility and immune-evasive properties, even a small percentage of severe cases can place a significant burden on healthcare systems, especially during peak transmission periods.
Impact on Vaccination and Immunity
The XBB variant poses challenges to existing immunity from both vaccinations and previous infections. Its recombinant nature means it carries mutations that help it partially evade the immune response. Although breakthrough infections have been observed, current vaccines still provide a level of protection, particularly against severe illness and hospitalization. Updated booster doses targeting Omicron subvariants are recommended to enhance immunity against the XBB strain.