The Omicron 5 (BA.5) variant of SARS-CoV-2 represents one of the most contagious evolutions of the Covid-19 virus. Although in most cases it causes milder symptoms compared to the early pandemic waves, it should not be underestimated, especially in vulnerable individuals.
Understanding how Omicron 5 presents, recognizing early warning signs, and knowing when to take action is essential both for protecting individual health and for reducing the spread of the virus.
What are the most common Symptoms of Omicron 5
Compared to earlier variants (such as Delta or the original Wuhan strain), Omicron 5 marks a clear shift toward a flu-like or flu-like illness, although with some distinctive features.
According to the most recent data, people who contract Omicron 5 or the current subvariants (such as KP.3 or XEC) almost always experience:
- Acute sore throat: often described as an intense burning sensation or a feeling of “shards of glass” when swallowing.
- Runny nose and nasal congestion: a constantly runny or severely blocked nose, often accompanied by frequent sneezing.
- Persistent cough: usually dry at first, but it may become productive (with mucus) at a later stage.
- Marked fatigue (asthenia): a deep sense of exhaustion that does not improve with rest.
- Headache: often tension-type, localized in the forehead or behind the eyes.
Shortly after the onset of the first symptoms, many patients report a feeling of general malaise, along with difficulty concentrating and daytime drowsiness.
👉 Unlike earlier variants, the loss of taste and smell is now much less common and tends to be partial or temporary.
Atypical symptoms and “New” warning signs
Beyond the classic respiratory symptoms, Omicron 5 has brought to the forefront clinical manifestations that were previously less common:
- Night sweats: many patients report sudden awakenings during the night completely drenched in sweat, even in the absence of high fever.
- Muscle and joint pain (myalgia): widespread aches, especially in the lower back and legs, similar to those of a severe flu.
- Gastrointestinal symptoms: nausea, mild diarrhea, or loss of appetite are being reported with increasing frequency.
- Mild neurological symptoms: feelings of dizziness, vertigo, and the so-called “brain fog”, characterized by mental cloudiness.
The loss of taste (ageusia) and smell (anosmia)—hallmark symptoms of COVID-19 in 2020—have now become rare with Omicron 5, occurring in less than 10% of cases.
How long do Omicron 5 symptoms last
The duration of symptoms varies depending on age, immune status, and pre-existing health conditions. On average:
- 4–7 days in vaccinated individuals or those previously infected
- 7–10 days in unvaccinated individuals
- Up to 14 days in fragile or immunocompromised patients
After the acute phase, a post-viral fatigue may develop, characterized by:
- persistent tiredness
- shortness of breath after mild exertion
- difficulty concentrating
These lingering symptoms may persist for days or weeks and should not be ignored, especially if they interfere with daily activities.
Incubation period and speed of transmission
One of the most critical aspects of Omicron 5 is its very short incubation period, which is typically 2–3 days.
This means that:
- people become contagious very quickly
- symptoms may appear after the virus has already been transmitted
- crowded and enclosed environments increase the risk of spread
It is precisely this characteristic that makes Omicron 5 extremely contagious, even in the presence of mild or initially unrecognized symptoms.
Omicron 5: when to see a doctor
Although Omicron 5 is generally less aggressive to the lungs, it can still cause serious complications, especially in vulnerable individuals or those who are not adequately protected.
Contact a doctor immediately or go to the emergency room if you experience any of the following:
- Shortness of breath (dyspnea): difficulty breathing even at rest or after minimal exertion (for example, walking a few steps).
- Chest pain: a persistent feeling of pressure or tightness in the chest.
- Low oxygen saturation: if you use a pulse oximeter and readings consistently fall below 94%.
- Mental confusion: disorientation, lethargy, or extreme difficulty staying awake.
- Persistent high fever: body temperature above 39°C (102.2°F) that does not improve after three days, despite the use of antipyretic medications.
In patients with asthma, COPD, heart disease, or immunosuppression, even an apparently mild form of Omicron 5 requires closer medical monitoring.
How to distinguish Omicron 5 from the flu or allergies
Many symptoms may overlap, but there are key differences that can help with identification:
- Seasonal flu → higher fever, intense chills, sudden onset
- Allergies → no fever, itchy eyes and nose, recurrent symptoms
- Omicron 5 → pronounced sore throat, intense fatigue, rapid incubation period
👉 Antigen or molecular testing remains the only reliable diagnostic tool to confirm the infection.
Management and treatment of symptoms
Today, the management of Omicron 5 is based on symptomatic treatment and common-sense medical care:
- Hydration: drink plenty of water to prevent dehydration caused by fever and to help thin respiratory secretions.
- Complete rest: essential to reduce the risk of developing Long COVID–related symptoms.
- Monitoring: regularly check body temperature and, if possible, oxygen saturation levels.
- Medications: the use of NSAIDs (such as ibuprofen) or paracetamol (acetaminophen) should always be discussed with your primary care physician.
Antibiotics are not indicated, except in cases of bacterial superinfection. In vulnerable patients, doctors may consider targeted antiviral therapies, which are most effective when started early.
Prevention and reinfections
Immunity acquired after infection or vaccination tends to decrease over time. To reduce the risk of reinfection, it is recommended to:
- regularly ventilate indoor spaces
- wash your hands frequently
- wear a mask in crowded settings
- keep COVID-19 vaccinations up to date
Official recommendations remain those provided by the Ministry of Health, the Istituto Superiore di Sanità and the World Health Organization.
ou can find further in-depth information in The Lancet – Clinical studies and research on Omicron
If, after reading this guide, you still have questions about your symptoms, or if respiratory issues persist, on InfinityDoc you can:
- book a targeted specialist visit
- request a rapid medical consultation
- learn more about diagnostic and respiratory monitoring pathways
👉 Acting promptly means protecting yourself and those around you.
FAQ – Omicron 5 Symptoms
Sore throat, sudden runny nose, and intense fatigue.
On average, 4–7 days in vaccinated individuals.
It rarely exceeds 38°C (100.4°F).
No, today it is less common and often temporary.
In case of shortness of breath, chest pain, or persistent fever.
Yes, immunity can decrease over time.
It is generally milder, but it should not be underestimated, especially in vulnerable individuals.
Yes. In 2026, we frequently observe a phenomenon known as “test timing mismatch.” With Omicron 5, the immune system reacts so quickly that symptoms (such as the characteristic “shards of glass” sore throat) may appear 1–2 days before the viral load in the nose is high enough to turn a rapid test positive.
Advice: If you have symptoms but the test is negative, repeat it after 36–48 hours. In the meantime, behave as if you were positive.
Clinical distinction has become subtle, but there are typical markers. The current flu tends to present with very high, sudden fever (above 39°C / 102.2°F) and severe, disabling joint pain. Omicron 5, on the other hand, almost always starts in the upper respiratory tract: extreme sore throat and nasal congestion dominate, while fever usually remains moderate (37.5°C–38.5°C / 99.5–101.3°F).
Intense night sweats have become a “signature” symptom of Omicron 5. On their own, they are not dangerous, but they indicate that the lymphatic system is working intensely.
What to do: Monitor your temperature, but do not panic if you do not have high daytime fever. Make sure to replenish electrolytes (potassium and magnesium), as nighttime fluid loss can cause fatigue and muscle cramps the following day.
Omicron 5 shows a strong affinity for the peripheral nervous system. Even after the virus clears, a mild residual neuroinflammation may persist, causing difficulty concentrating and chronic fatigue.
Warning sign not to ignore: If 15 days after testing negative you still struggle to climb stairs without breathlessness or frequently forget common words, consult your doctor for post-viral screening—it may represent an early form of Long COVID.
