Sudden Fever: Is It Flu or a New Variant Virus?

Sudden high fever?

On September 29, I suddenly experienced a fever, body aches, loss of appetite, night sweats, a swollen headache, and mild nausea, but my sense of taste and smell, as well as bowel movements, were normal.
On September 30, my fever peaked at 39 degrees Celsius.
By October 1, the fever and other symptoms had noticeably improved.
By October 2, I no longer had a fever or body aches, but I still experienced night sweats and headaches (the headaches occur during sudden movements, such as shaking my head or getting up).
On October 3, I started to feel a tickle in my throat and the urge to cough (prior to this, I had no cough, nasal congestion, or runny nose).
I would like to know if these symptoms are more indicative of influenza or if there is a possibility of a variant virus.

Mr. Li, 20~29 year old female. Ask Date: 2021/10/03

Dr. Yang Zongyan reply Influenza

Regarding fever symptoms, they are more likely to be associated with influenza, but there is also a possibility of a variant virus.
Clinically, it is difficult to differentiate between them, so it is important to consider any relevant TOCC (Travel, Occupation, Contact, Cluster) history, travel history, and whether family members or colleagues are experiencing similar symptoms.
Therefore, it is still recommended to seek medical attention promptly for treatment or to undergo influenza/COVID-19 antigen testing to determine the exact cause.

Reply Date: 2021/10/03

More Info

When considering the symptoms you've described, it is essential to understand that both influenza (the flu) and COVID-19 can present with similar clinical features, making it challenging to distinguish between the two based solely on symptoms. Your sudden onset of fever, body aches, loss of appetite, sweating during sleep, headache, mild nausea, and subsequent throat discomfort could align with either condition.

The timeline of your symptoms is also noteworthy. You experienced a sudden fever that peaked at 39 degrees Celsius, followed by a gradual resolution of most symptoms within a few days. This pattern is often seen in viral infections, including both influenza and COVID-19. The fact that your fever subsided and other symptoms improved significantly by October 2, with only lingering mild symptoms, suggests that your body was effectively fighting off the infection.

However, the emergence of throat irritation and a cough on October 3 raises some questions. While throat discomfort can occur with both influenza and COVID-19, it is also a common symptom of other viral infections, such as the common cold or even allergies. The absence of nasal congestion or runny nose further complicates the picture, as these symptoms are typically associated with upper respiratory infections.

To determine whether your illness was more likely the flu or a variant of COVID-19, it is crucial to consider additional factors, such as exposure history (TOCC: Travel, Occupation, Contact, and Cluster), vaccination status, and any recent outbreaks in your community. If you have been in close contact with someone who tested positive for COVID-19 or if there has been a known outbreak in your area, this could increase the likelihood of a COVID-19 infection.

Given the current landscape of viral infections, including the emergence of new variants, it is also possible that your symptoms could be attributed to a variant of the virus. Variants can sometimes present with atypical symptoms or milder manifestations, particularly in individuals who have been vaccinated or previously infected.

In any case, the best course of action is to seek medical evaluation. Testing for both influenza and COVID-19 can provide clarity on the cause of your symptoms. Rapid antigen tests or PCR tests for COVID-19, as well as a flu test, can help determine the specific virus responsible for your illness. Additionally, a healthcare provider may recommend further evaluation if your symptoms persist or worsen, as they can assess for other potential causes of your fever and throat discomfort.

In summary, while your symptoms could suggest either influenza or a variant of COVID-19, definitive diagnosis requires testing and consideration of your exposure history. It is always advisable to consult with a healthcare professional for personalized advice and management based on your specific situation.

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