The superflu, the unwanted guest of Christmas meals

Do you have the flu? These are the days you are most contagious

This year the celebration of christmas It will coincide, in much of Spain, with the peak of the flu, which has been brought forward in the northern hemisphere by about a month compared to the last two seasons.

An early start of the epidemic, which has been related, according to organizations such as the World Health Organization (WHO) or the European Center for Disease Control (ECDC), to the expansion of the subclade K of ‘variant’ A H3N2 –It does not seem to be more serious, but it could be easier to generate cases.

Specifically, according to the latest report published by the Carlos III Health Institute (ISCIII)In the middle of this month, record numbers of detections in primary care would have already been reached.

With data from December 8 to 14, all the indicators collected in primary care had exceeded already the maximums recorded since 2020. Detections in health centers were in 195.9 cases per 100,000 inhabitants, the positivity of the tests reached 55.2% and the estimated total incidence reached 446.6/100,000.

In hospitals, the rate had not yet reached the highs of other seasons last week: it stood at 9 cases per 100,000, while in 2023-2024, 16.6 were reached. Of course, the positivity in these centers had been located in similar percentages to those of the peak two years ago (42.9%), already reaching 42%, as of December 14, 2025.

Christmas and infections

Thus, taking all this data into account, it is very likely that this Christmas a family member is sick and cannot attend lunch or dinner or that, when they go to the health system, they must face long waits, due to the saturation of Health.

A tension in the system, which has already been denounced by unions such as CSIF and SATSE or by the Spanish Society of Emergency Medicine (SEMES) and the Spanish Society of General and Family Physicians (SEMG).

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This 2025-2026 season, the flu has arrived earlier and, in principle, stronger than usual in the northern hemisphere. The main culprit is a variant of the influenza A(H3N2) virus known as subclade K (formerly J.2.4.1).
1/10 pic.twitter.com/3tLKofe4v0

— Rafa Toledo (@alfwarrior) December 20, 2025

Symptoms

It should be remembered that flu infection does not always manifest with the same symptoms. Some of the infected people will have a mild or moderate condition, others will not develop the pathology, even if they are carriers of the virus, and the least may have serious respiratory difficulties or a decompensation of an underlying chronic disease, which can lead them to the hospital.

As explained in a SEMES statement, The classic clinic usually includes:

• muscle pain
• Shivers
• Dry cough (without expectoration)
• Fever
• Headache
• Sore throat
• In some cases vomiting and diarrhea

Treatment

From SEMES they assured that the treatment for mild or moderate symptoms consists of:

• Relative rest.
• Drink plenty of fluids.
• Avoid the consumption of alcohol and tobacco.
• Take medication that improves flu symptoms (medicines to reduce fever, headache…).
• The flu is caused by a virus so Antibiotics do not improve symptoms or speed healing.
• Do not give aspirin to children or adolescents (could cause a rare but serious syndrome called Reye’s Syndrome).

“Complications of the flu are not frequent and they occur especially in older patients or patients with chronic diseases,” they added.

Recently, a team of researchers from ISCIII has shown that the flu caused more than 33,000 hospitalizations in Spain, 1,811 admissions to Intensive Care Units (ICU) and 1,825 deaths between October 2024 and May 2025, becoming the main respiratory pathogen in the country.

When is it infected?

As for the transmission, this occurs mainly “from 1 day before symptoms start, until 7 days afterwith a maximum contagion capacity the first 3“, they added.

The vaccine, the most effective weapon

In order to prevent deaths of vulnerable people, the most effective weapon that exists to date is to prevent suffer from a serious condition when they become infected. And this is achieved through mass vaccination of these risk groups. It should be remembered that these doses are not foolproof and are not 100% effective, but they can significantly reduce the likelihood of complications.

They are recommended to the following groups:

• 60 years or more.
• Minors under 60 years of age with risk conditions.
• Pregnant women.
• Health center staff.
• Workers of essential public services such as State Security Forces and Corps or firefighters.
• Smoking people.
• People with direct occupational exposure to animals.
• Child population.
• Minors between 6 and 59 months.

At the beginning of December, the first results of the Sanofi Gripometer 2025-2026, which revealed that the percentage of people over 65 years old already vaccinated against the flu this year in Spain reached the 56.1%while in the population between 60 and 64 years old it reaches 24.7%both figures very similar to those last year on the same dates, located in the 56.3 and 25.3%, respectively.

Hygiene measures

On the other hand, there are hygiene measures that can be applied, especially if you are in the presence of very vulnerable people.

These are some tips from SEMES:

1. Wear a mask if you have symptomsespecially in poorly ventilated spaces, and in the presence of vulnerable people or when working with patients with compatible conditions.
2. Wash your hands frequently: before eating, handling food, after leaving the bathroom and after blowing your nose or coughing.
3. Cover your mouth and nose when sneezing or coughing: If you can with your arm or a tissue instead of your hand.
4. Use disposable tissues: Throw them away after each use, do not store used ones or leave them on tables or nightstands.
5. Avoid kisses and very close contactas well as sharing glasses, cutlery, towels and other objects that may have been in contact with saliva or secretions.
6. If there is someone in your house with the flu, clean common surfaces more frequently (doorknobs, sinks, handles) with the usual cleaning products and ventilate the rooms more often by opening the windows.
7. Lead a healthy life: sleep well, eat healthy, drink water, physically active, avoid alcoholic beverages and tobacco. It is also advisable to shower with hot water and humidify the air.