The incidence of influenza has started to decline in Spain. This was confirmed on Friday by the latest epidemiological report on respiratory diseases published by the Carlos III Health Institute (ISCIII), with data relating to the week preceding the Christmas holidays, between December 15 and 21, according to which the rate of influenza syndrome increased from 197.6 to 192.6 cases per 100,000 inhabitants. However, if we focus on the incidence by age group, infections decrease in all age groups except those over 60, even if the incidence among the oldest remains lower than the national average.
The recent document confirms the downward trend that the bulletins of the different autonomous communities have already communicated this week. The flu thus reduced its transmission at the community level the week before the Christmas holidays. Some communities such as Catalonia, the Basque Country or Galicia have raised the possibility of having already reached their maximum number of infections, while asking caution to avoid a “rebound” after the celebrations and meetings on these dates.
By age groups, People over 60 now constitute the population among which the flu continues to increase. Specifically, according to ISCIII data, the flu rate among people aged 60 to 69 fell from 96.6 to 69 during the third week of December. 115.3 cases per 100,000 inhabitants. In the 70-79 age group, the rate of influenza infections at the community level (primary care) increased from 84.7 to 106.5 cases per 100,000 population. Finally, among citizens aged 80 or over, the flu rate also increased, although to a lesser extent: from 91 to 93.5 cases per 100,000 inhabitants.
Even though infections have continued to grow among the elderly, who are most vulnerable to the risk of developing serious illness after infection, the truth is that transmission among those over 60 does not exceed the general rate that includes all age groups, which amounts to 192.6 cases per 100,000 inhabitants in the last week analyzed. While the escalation of infections began a month ago, vertical chart for younger age groups (from birth to 19 years), the increase among the oldest age groups (from 60 years) has been recorded since the start of the epidemic at lower levels.
Income is maintained
HAS hospital levelflu admissions, which two weeks ago exceeded the peak of the previous winter, remained stable during the third week of December, down very slightly from 9.3 to 9.2 cases per 100,000 inhabitants.
In this case, The most affected remain those over 80 years old. and those less than a year oldbut in both age groups, the estimated incidence decreased during the last week analyzed. Concretely, among those over 80, hospitalizations for influenza increased from 58.1 to 52.7 cases per 100,000 inhabitants. Among the babies of less than a yearhospitalizations recorded a notable drop and they fell from 43.5 to 16 cases per 100,000 inhabitants during the third week of the month.
Among those increasing their income are people aged 60 to 69 and children aged one to four. In this second case, the estimated weekly hospitalization rate increased from 11.8 to 14.9 cases per 100,000 inhabitants. Among people in their sixties, the increase is smaller and goes from 10.7 to 11.9 income per 100,000 inhabitants.
According to the report, in terms of severity, since the start of the season (end of September), cases hospitalized for influenza presented 19.9% pneumonia, 4.5% ICU admissions and 3.9% mortality. THE symptoms from the flu the most common are the cough (in 86.7% of cases) and the fever (in 84.7% of cases), followed by general malaise (79.3%), nasal congestion (69.1%) and sore throat (61.9%).
At the syndromic level, the rate of respiratory infections at the general level in Spain stands at 834.1 cases per 100,000 inhabitants (compared to 811.8 cases the previous week) and its transmission presents a “low” intensity. The percentage of positivity for influenza fell to 48% during the last week analyzed (compared to 54.7% the previous week); 1.3% for SARS-CoV-2 (compared to 0.7% the previous week); and 6.6% for respiratory syncytial virus (RSV), which causes bronchiolitiswhich increases compared to last week, where the positivity percentage was 5.3%. RSV is also increasing in hospitalswhose estimated hospitalization rate increases from 2.6 to 3.1 cases per 100,000 inhabitants.
New vaccine study
On the other hand, this Friday an international investigation carried out in collaboration with the ISCIII was made public which demonstrated in a preclinical mouse model that vaccination against influenza, in addition to protecting against the virus, strengthens the response of the immune system to reduce mortality linked to secondary bacterial infections.
The work, published in Journal of Virologywas led by researchers from the Icahn School of Medicine at Mount Sinai, in New York (United States), and benefited from the Spanish participation of a team from the National Center of Microbiology (CNM) of the ISCIII and groups from the CEU San Pablo University of Madrid.
Secondary bacterial infections, such as those caused by Streptococcus pneumoniae, are a leading cause of serious complications and death during annual influenza epidemics among at-risk individuals, such as the elderly and immunocompromised patients.
The results of this study open the door to new knowledge for human health, as they can help understand how bacterial infections associated with influenza worsen disease and how vaccination can mitigate this risk, ISCIII reported in a press release.
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