Flu cases double in seven days: everything you should do in the coming weeks

BarcelonaIt is the underestimated epidemic, the one that is described as severe coldBut the behavior of the flu is unpredictable. Every year, this virus causes hundreds of hospitalizations and deaths among the elderly and vulnerable. Many end up suffering from illnesses stemming from pneumonia, respiratory failure, or exacerbations of chronic conditions such as diabetes. These are pathologies that could have been avoided or minimized by following preventive measures. This Tuesday, Catalonia officially entered the period of accelerated flu transmission: the number of cases has doubled, there are 35 hospitalized patients, and five of them are in serious condition. What to do now?

The latest data from the Catalan Infection Surveillance Information System (SIVIC) confirms that the flu wave is already here. The increase began five weeks ago, earlier than usual, and faster than in previous years. In the last week, from November 24 to 30, 11,122 diagnoses were registered in primary care. The previous week there were 6,006. The Catalan Health Department anticipates that the peak of the outbreak will arrive in three weeks, coinciding with the Christmas holidays. This was explained by the Minister of Health, Olga Pané, in an interview on Catalunya Ràdio. The Minister argued that current figures exceed the moderate level and predicts that the high level, defined as approximately 218 cases per 100,000 inhabitants, will be reached "in about two weeks." She also explained that the current situation is already placing a significant strain on the healthcare system and reiterated the recommendation to get vaccinated, especially for high-risk groups. Furthermore, she expressed her support for making masks mandatory in certain settings and announced that the Department will bring this proposal to the meeting between the Ministry of Health and the regional governments taking place this Wednesday.

In the last seven days, cases have increased by 85%, and the incidence is high: an estimated 164 cases per 100,000 inhabitants (compared to 82 last week). Although rhinovirus, the cause of the common cold, is the most prevalent (39.3% of positive samples1), all indications are that an epidemic situation will soon be reached.

The ages of those infected show that the pathogen is already being actively transmitted in schools and workplaces: children aged 5 to 14 and young adults (15 to 44 years) represent more than 60% of cases. However, as usual, the brunt of the consequences impacts the elderly and the very young. So far, most flu-related hospitalizations (a total of 35) are among patients over 60 years old. Twenty people in this age group have required hospitalization. Of the other 15, five are under 4 years old.

The relationship between young children and the elderly is one of the most important chains of flu transmission, emphasizes Alba Sanvicente, director of the primary care team (EAP) in Vilassar de Mar at the Catalan Health Institute (ICS). "Many vulnerable people act as caregivers for children, so vaccination is the best prevention tool available," she states. The nurse reminds us that immunization is the only shield to protect ourselves and the community. "It helps reduce symptoms and complications. 75% of those admitted to the intensive care unit (ICU) for respiratory viruses last year were not vaccinated," she adds. This year, there are already five people in the ICU, which shows that one in four people admitted for the flu suffers complications. Three of the patients are between 0 and 60 years old, and two are older.

Agreed recommendations

This Wednesday, the Ministry of Health and the regional governments approved the framework document of recommendations to improve the response to the seasonal respiratory virus epidemic. The main changes include the establishment of four risk levels based on detected transmissibility indicators—baseline, low, high, and very high—and general recommendations such as promoting vaccination and specifying when and where mask use is necessary. In cases of high transmissibility, visitation policies will be reviewed. Regarding detection and data collection, surveillance systems for acute respiratory infections will be implemented: the Daily Mortality Monitoring System (MoMo), the Vaccination Information System (SIVAMIN), and data on hospital and intensive care unit occupancy. At the low or medium epidemic level, mask use is recommended in sensitive areas of hospitals, such as oncology or transplant units, for both healthcare professionals and patients and their companions. At the same time, the continued use of this protection is maintained among workers with symptoms in nursing homes. Regarding the high level of the epidemic, the widespread use of masks is advised in common areas of healthcare centers, such as waiting rooms or emergency departments, and the visiting policy in nursing homes and centers for people with disabilities will be reviewed. Vulnerable individuals are advised to use face coverings in enclosed spaces without adequate ventilation. Finally, the document maintains that in situations of a high or very high level of epidemic, it is necessary to activate extraordinary coordination between territories through meetings of the Plenary of the Interterritorial Council of the National Health System. In such cases, health authorities may establish exceptional measures for the control of transmission in certain contexts or particularly exposed groups.

This season, the predominant strain is the A (H3N2) influenza subtype, known as variant K, which has also been detected in Europe and Southern Hemisphere countries, where the epidemic peak has already passed. Unusually high disease severity has not been observed, but there is a certain mismatch—the phenomenon that occurs when the influenza strain chosen to design a year's vaccines does not correspond to the predominant strain that year—which reduces the vaccines' potential to prevent infection but not to protect against it.

The World Health Organization (WHO) recommends that influenza vaccination coverage in older adults and vulnerable groups be 75% or higher. Currently in Catalonia, coverage is approaching 64% for those over 80 and 50% for those between 70 and 79. There is room for improvement, and the Catalan Health Department is allowing vaccination for anyone who wants it starting this Monday, even those without underlying health conditions. For example, if you live with vulnerable people or work in an environment prone to infection. "Vaccination in early childhood can help break the chain of transmission," Sanvicente adds.

But currently, flu vaccination coverage in children aged 6 to 59 months is only 36%, far from the WHO target, even though influenza A is now the most common virus (50% of cases) in this age group. In fact, it has even surpassed respiratory syncytial virus (RSV), which traditionally preceded the flu epidemic in children and now accounts for 5% of infections.

This shift is mainly due to vaccination: 93.5% of babies born between April and September and 71.7% of those born between October and May have received the vaccine against the virus that causes bronchiolitis, meaning that 89% of babies are protected against this virus.

Masks and teleworking

The Catalan Health Service (Salut) also recommends wearing a mask in shared spaces, especially in healthcare facilities. "We have never stopped offering masks to people who arrive with doubtful symptoms or general, digestive, or respiratory discomfort," explains Sanvicente, who reminds us that everyone in this situation should wear a mask or request one at the reception desk, including those who haven't come in because they've scheduled an in-person appointment by phone or through the "Mi Salud" (My Health) app. The Catalan Health Service (ICS) nurse is emphatic: in the workplace, both at the peak of the illness and with mild symptoms, the recommendation is to work remotely whenever possible. If not, she recommends wearing a mask, maintaining good and frequent hand hygiene, using disposable tissues, ventilating spaces, and informing supervisors of the situation.