XBB.1.5 COVID Variant: Symptoms, Spread, and What to Know

Emerging mutations demand updated precautions to curb community transmission.

By Medha deb

Created on Sep 22, 2025

Emerging mutations demand updated precautions to curb community transmission.

The emergence of the XBB.1.5 Omicron COVID-19 subvariant—popularly known as the “Kraken” variant—has caused significant concern and questions as it quickly became the dominant strain in several regions, especially the Northeastern United States. Understanding its unique characteristics, transmission rates, symptom patterns, and recommended protective measures is essential as public health officials and researchers continue to monitor the variant’s impact worldwide.

Understanding XBB.1.5: What Sets This Variant Apart?

XBB.1.5 is a recombinant subvariant of Omicron, created through the combination of two BA.2 Omicron lineages. This new variant was first identified in the United States in late 2022, rapidly ascending to dominance in January 2023 in certain regions, due to its enhanced transmissibility and ability to evade immunity from previous infections and vaccinations.

As the XBB.1.5 variant raises significant concerns, it's crucial to stay informed about its symptoms and impacts. To deepen your understanding, consider exploring our detailed overview of the XBB COVID-19 ‘Nightmare Variant’ symptoms, risks, and protection strategies. This guide provides essential insights that can help you navigate the ongoing challenges posed by this evolving virus.

Origin: Recombinant of two BA.2 Omicron sublineages
Detection: First identified in the U.S. in October 2022
Spread: Rapidly became the most prevalent variant in the Northeastern U.S. by early 2023, accounting for over 80% of cases in states like New York and New Jersey
Global Presence: Detected in at least 43 U.S. states and 74 countries globally

Mutation Details:
XBB.1.5 carries mutations in the spike protein, notably enhancing its ability to bind to the ACE2 receptor in human cells, potentially making it more transmissible than prior subvariants.

How Contagious Is XBB.1.5?

One of the main concerns surrounding XBB.1.5 is its high transmission rate. Epidemiological models and real-world data indicate that this subvariant spreads more efficiently than earlier Omicron offshoots. This acceleration is reflected in its replacement of prior dominant strains in regional case reports.

Understanding the broader implications of prevalent COVID variants like JN.1 is vital for public health. For those who seek comprehensive guidance, check out our resource on JN.1 COVID Variant: Symptoms, Risks, and How to Stay Protected. Stay educated on safeguards you can take to mitigate risks associated with emerging threats.

Transmission Rate: Rapid growth in case numbers; higher R-value (reproduction number) compared to previous variants
Immune Evasion: Increased ability to bypass immunity from previous infections and vaccinations, though vaccines continue to reduce risk of severe illness

It is important to note that despite its increased transmissibility, public health experts have not observed a corresponding increase in disease severity at the population level thus far.

Symptoms of XBB.1.5: What Do We Know?

The primary symptoms associated with XBB.1.5 infections closely mimic those seen with previous Omicron variants. While severe outcomes are still possible—particularly among older adults and high-risk populations—the majority of cases present with mild to moderate symptoms.

To understand how newer variants like FLiRT and LB.1 compare to XBB.1.5, it's essential to broaden your knowledge. Dive into our in-depth article on FLiRT and LB.1: Understanding the Latest COVID Variants and Their Symptoms. Designed to keep you updated, this piece breaks down key distinctions in symptom presentation and health impacts.

Fever or chills
Cough (can be dry or productive)
Sore throat (often described as severe or “razor blade throat”)
Congestion or runny nose
Shortness of breath or difficulty breathing
Loss of taste or smell (less common than with previous variants)
Muscle or body aches
Headache
Fatigue
Nausea or vomiting
Diarrhea

Notably, the “classic” COVID-19 symptom of sudden loss of taste or smell has become less frequently reported with Omicron subvariants compared to former strains like Delta or Alpha. However, it can still occur in isolated cases.

Symptom Duration

The typical course of symptoms lasts five to seven days, but individual experiences can vary significantly. Some symptoms like fatigue and cough may persist longer in certain individuals.

Recognizing fatigue and tiredness as potential signs of COVID can be crucial for your health response. For a deeper exploration, visit our guide on Fatigue, Muscle Soreness, and Tiredness: Key Signs of Omicron COVID-19 Symptoms. This resource is tailored to help you identify symptoms early and take appropriate action.

Is XBB.1.5 More Severe Than Earlier Variants?

There is currently no direct evidence that XBB.1.5 causes more severe disease than previous Omicron variants. Clinical observations and preliminary research suggest that the severity of symptoms has not increased, and in many cases, may be less pronounced. This may be partially due to:

Retained immunity (from vaccines or previous infections) in much of the population
Omicron’s tendency to remain primarily in the upper respiratory tract, leading to milder symptoms than variants that impacted the lungs more aggressively

Still, some groups may face higher risk for complications, including:

Elderly individuals
People with underlying health conditions (e.g., heart disease, diabetes, immunosuppression)
Unvaccinated or undervaccinated individuals

Understanding how symptoms evolve in vaccinated individuals is essential for informed decisions. For comprehensive insights, explore our informative article on How Long Do COVID-19 Symptoms Last If You’re Vaccinated?. Equip yourself with knowledge that can help navigate treatment options and expectations.

Comparing XBB.1.5 Symptoms to Previous COVID Variants

Variant	Most Common Symptoms	Severity	Unique Features
Alpha/Delta	Loss of taste/smell, high fever, shortness of breath, cough	Moderate to severe	Frequent loss of taste/smell; higher risk of pneumonia
Omicron BA.1/BA.2	Sore throat, congestion, cough, headache, fatigue	Mild to moderate	Upper airway focused, less loss of taste/smell
XBB.1.5	Sore throat, cough, congestion, headache, fatigue	Mild to moderate (population-level)	High transmissibility; strong immune evasion

What Should You Do If You Have Symptoms?

Test for COVID-19: Any unexplained respiratory symptoms—especially if resembling those listed above—should prompt immediate testing (at-home rapid antigen or PCR as available).
Isolate if Positive: If you test positive, follow public health guidelines regarding isolation to reduce the risk of spreading the virus.
Monitor Symptoms: Watch for worsening symptoms, such as difficulty breathing, chest pain, persistent fever, confusion, or inability to stay awake. Seek medical attention if these occur.
Contact Healthcare Provider: Especially if you are in a high-risk group or symptoms are severe, reach out to your provider for guidance, including whether you may be eligible for antiviral treatment.

If you're dealing with COVID-19 symptoms, knowing how to treat them at home is vital. Discover effective methods and essential steps in our comprehensive guide on How to Treat COVID-19 Symptoms at Home: Essential Steps for Recovery. This knowledge can empower you to manage your health proactively.

Testing remains a key public health recommendation even though symptoms may be mild or resemble common colds and flu. Timely identification ensures appropriate treatment, isolation, and the safeguarding of vulnerable populations.

Vaccine Effectiveness Against XBB.1.5

Research has shown that existing COVID-19 vaccines—while potentially less effective at preventing infection from XBB.1.5 due to the variant’s immune-evasive properties—still provide significant protection against severe outcomes, hospitalization, and death.

Bivalent boosters are recommended for eligible individuals; these target Omicron and its subvariants more specifically.
Vaccination or recent booster offers the best available protection, especially for vulnerable populations.

The CDC and World Health Organization advise everyone aged six months and older to stay up to date with COVID-19 vaccinations and boosters as soon as they become eligible.

Mitigation and Prevention: Reducing Risk of Infection

With XBB.1.5’s high transmissibility, layered prevention remains critical. Recommendations include:

Stay current with COVID-19 vaccines and boosters
Mask indoors in crowded or poorly ventilated settings, especially in regions with high transmission rates
Practice frequent hand hygiene
Use high-quality masks (e.g., N95, KN95) for added protection
Improve indoor ventilation where possible
Consider regular testing ahead of gatherings, travel, or following exposure—particularly if you have vulnerable individuals in your household

Who Is Most at Risk for Severe Disease?

Adults age 65 and older
Individuals with chronic medical conditions
People with weakened immune systems
Unvaccinated individuals

Those falling into these groups should be especially vigilant about prevention measures and contact their healthcare provider promptly if experiencing symptoms.

Mild vs. Severe COVID-19 Symptoms: When to Seek Emergency Care

Mild symptoms: Sore throat, runny nose, mild cough, headache, low-grade fever, body aches
Severe symptoms requiring immediate medical attention:
- Difficulty breathing or shortness of breath
- Persistent chest pain or pressure
- New confusion or inability to wake/stay awake
- Bluish lips, nail beds, or skin tone changes

Do not delay in seeking care if you or someone you know develops these emergency warning signs.

How Is XBB.1.5 Diagnosed?

COVID-19—including XBB.1.5 and other variants—is diagnosed using the same testing platforms as previous variants. This includes:

Nasal or throat swab PCR tests (laboratory-based; can detect the viral genetic material)
Rapid antigen tests (at-home; less sensitive but provide results in minutes)

Genomic sequencing is required to definitively identify XBB.1.5, but this detail is not necessary for personal treatment or public health management. Routine diagnostic tests suffice for isolation and clinical care decisions.

Frequently Asked Questions (FAQs) about XBB.1.5

Q: Is XBB.1.5 the most contagious COVID-19 variant?

A: Yes, current research and epidemiological patterns indicate that XBB.1.5 is one of the most transmissible variants to date, due to its unique mutations and immune-evasive capabilities.

Q: Are symptoms from XBB.1.5 different from older variants?

A: The most reported symptoms are similar to those of previous Omicron subvariants—primarily sore throat, cough, congestion, headache, and fatigue. Sudden loss of taste or smell is now less common.

Q: Can the COVID-19 vaccines protect me against XBB.1.5?

A: While the vaccines may not fully prevent infection with XBB.1.5, especially as immunity wanes, they continue to provide strong protection against severe illness, hospitalization, and death.

Q: Should I mask and test even if I have mild symptoms?

A: Yes. Even mild symptoms like sore throat and congestion should prompt testing and, if positive or pending, masking and isolation to protect others—especially those at high risk.

Q: Can you get long COVID from an XBB.1.5 infection?

A: Yes. Although the risk of chronic symptoms may be somewhat lower with Omicron-related infections than with Delta, long COVID can still occur after mild or moderate infections.

Key Takeaways and Staying Informed

XBB.1.5 is currently one of the most prevalent and transmissible COVID-19 variants.
Symptoms resemble those of previous Omicron subvariants, with a focus on the upper respiratory tract.
Vaccination and boosters offer ongoing protection from severe illness and hospitalization.
Testing remains crucial for differentiating COVID-19 from flu and colds.
Layered prevention—vaccinations, masking, ventilation, and prompt testing—remains the most effective public health strategy.

For the latest official updates and recommendations on XBB.1.5 and COVID-19, refer to guidelines from the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO).

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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