Decoding Symptoms of the Omicron Variant and Subvariants

February 15, 2024

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As the SARS-CoV-2 virus behind COVID-19 continues evolving, each new variant brings distinctive mutations affecting transmissibility, disease severity, and even symptoms. Understanding the latest clinical patterns helps inform testing and isolate sooner.

This guide summarises symptom profiles associated with Omicron lineages and subvariants explaining why certain strains feel more like common colds, while others trigger full-body misery.

Omicron: Caused a Symptom Shift

Emerging in late 2021, the heavily mutated Omicron variant triggered a major symptom shift often presenting earlier in the upper, rather than lower respiratory tract.

Omicron Infection Sites

  • Nose
  • Throat
  • Sinuses

Chest Involvement

Less pneumonia or shortness of breath. Cough tends to be dry.

Common Symptoms

  • Sore throat
  • Runny nose
  • Cough
  • Headaches
  • Sneezing
  • Fatigue

So while still potentially serious in vulnerable groups, Omicron felt more akin to an ordinary cold for many younger, vaccinated people.

Omicron Subvariants: Ups and Downs

Post-Omicron, new spins on this variant arose with their own profiles.


  • Rose swiftly showing high transmissibility
  • Symptoms copied Omicron classic


  • More rapidly spreading mutation
  • Milder infections on average
  • Shorter symptom duration

BA.4 & BA.5

  • Dominant globally through 2022
  • Keenly evaded prior immunity
  • More fever, chills, coughing reported


  • Concerning mutations present
  • But symptoms remain Omicron-like
  • Must monitor carefully


  • Hybrid Omicron/Delta origins
  • Harsher symptoms re-emerging
    • High fever, breathing issues, diarrhea

BA.5 Symptom Profile

The first Omicron spawn wielding enough change to re-shape disease, BA.5 and cousins, makes it tougher to shrug off as ‘just a cold’.

Fever + Chills

BA.5 leans influenza-esque reviving higher fevers and rigor. Bed-rest recommended for a few rougher days.

Cough + Chest Discomfort

Cough shakes off dryness turning wetter, deeper with chest congestion. Still no pneumonia prevalence jump.

Fatigue + Brain Fog

Crashing fatigue and mental murkiness return in force for some, disrupting work and focus. Effects seem to hit younger groups more.

GI Troubles

About 20% experience diarrhea or other stomach upset last seen with 2020 variants.

XBB Subvariants: New Concerns

Rising star recombinant XBB sparks fresh worries pairing Omicron evasiveness with Delta virulence.

Respiratory Distress

ERP expert Dr. Eric Topol warns XBB marks:

“First time we’ve seen a signal of lung injury from Omicron or any of its sublineages.”

Tracking hospital metrics matters.

Systemic Symptoms

Full bodied flu-esque illness with headache, sore throat, fever, chills, muscle and joint pains.

Other Red Flags

  • Shortness of breath
  • Chest tightness
  • Heart palpitations

XBB severity requires vigilance.

COVID-19 Infection Timeline

Understanding symptom changes across the ∼10-day infection span guides safe management.

Day 1

  • Exposure to virus
  • Asymptomatic

Day 2-4

  • Early symptoms emerge
    • Fatigue, headache, fever
  • Routine seems normal otherwise

Day 3-6

  • Flu-like misery peaks
    • Chills, body aches
  • Upper respiratory dominance
    • Sore throat, sinus pain

Day 7

  • Symptoms improve noticeably
  • Energy returns

Day 8-10

  • Resolution for most
  • Isolation can end

But severity and duration alter across variants, with unvaccinated also faring worse.

FAQs: Omicron Variant Symptoms

Do Omicron symptoms differ from Delta?

Yes. Omicron leans upper respiratory: runny nose, congestion, sore throat, headaches. Delta was lower respiratory: pneumonia, shortness of breath, hypoxia.

How long do Omicron symptoms usually last?

On average, acute symptoms last 5-7 days with Omicron instead of 10-14 days with prior variants. But lingering fatigue, brain fog or loss of smell can bother some longer term.

What percentage get long COVID after Omicron?

UK data suggests around 4.5% have persisting symptoms >12 weeks. But most Omicron long COVID is less severe than with pre-Omicron variants. Vaccination further lowers long term risk.

Do new Omicron subvariants like XBB cause worse symptoms?

Yes, recombinant variants like XBB revives fever, pneumonia and systemic symptoms more similar to past dominant strains with evidence of lung impacts reemerging.

What distinguishes BA.5 symptoms from original Omicron?

BA.5 evokes higher fever, chills, chest congestion, wheezing, diarrhoea and headaches compared to classic Omicron. It also disproportionately sickens younger people.

Key Takeaways

  • Omicron mutation made COVID-19 illness more cold/flu-like
  • Subvariants like BA.5 and XBB restore some prior severity
  • Monitoring symptom changes aids prompt testing and care access
  • Outcomes still worse for unvaccinated groups

Staying alert to symptom patterns helps gauge risks so those vulnerable get treatment fast while communities curb transmission.

Though the virus keeps changing, each lesson learned brings us closer to stable coexistence where COVID-19 no longer devastates lives and livelihoods unnecessarily.

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