Spain and the whole of Europe are facing an unusual flu season, putting health authorities on alert. The virus has arrived earlier than usual, and genetic analyzes have revealed that it is different from the virus that has spread in previous winters, so you will find a less immune population.
Spain entered the epidemic phase on Thursday, according to the latest report published by the Carlos III Health Institute. The rate of influenza syndrome – a diagnosis made in consultations, although not always with viral confirmation – is 40.1 cases per 100,000 inhabitants compared to 35.2 last week. This is the first time this season that the 37 cases identified as the epidemic stage threshold have been exceeded, and expectations indicate that they will continue to grow strongly. The estimate of total influenza cases – an indicator calculated taking into account other variables – rose to 112.2 cases per 100,000 population compared to 80.5 last week.
The rapid growth in trading and changes in the virus raise concerns that this year’s wave may be more significant than previous ones. The European Center for Disease Control (ECDC, the European Union’s public health agency) urged countries to accelerate vaccination campaigns and prepare health systems for a possible increase in hospitalizations.
Last winter’s influenza epidemic was “less severe” than the previous one, according to a report issued by the Ministry of Health. Despite this, it caused the death of 1,825 people and the hospitalization of more than 33,000 people, according to a study conducted by Spanish researchers and published in the magazine. Influenza and other respiratory viruses.
What follows are the seven keys to a season that has already begun to hit much of Spain.
Early bird virus
“Unusually early detections of influenza have increased in EU countries (…). The progress is three to four weeks.” And so begins a risk report published by the European Center for Disease Control and Prevention that warns of something that can already be seen in Japan. The Asian country detected an increase in cases in August and declared the official start of the flu season in September, the second earliest in two decades.
“Usually influenza starts in the Northern Hemisphere in Asia and spreads to Europe, so we try to predict. We are moving forward, for example, the vaccination date for children (a group that has an important role in the spread of the virus) to the third week of September instead of mid-October,” explains Catalonia’s Minister of Public Health, Esteve Fernández.
Among other communities, the Basque Country also tried to adapt to the new situation and installed a vaccinodrome In Bilbao to accelerate the campaign after discovering an increase in hospitalizations in Bizkaya.
Different virus
Two subtypes of influenza A viruses have been behind waves in recent years: H1N1 and H3N2. The letters indicate two proteins found on the surface of the pathogen, and the numbers indicate their variants. “There are two changes this year. The first is that we had a lower presence of the H3N2 virus for a few seasons and now it is dominant. The second is that in addition, this virus has developed several mutations to form a new subclass, K,” explains microbiologist Diego García Martínez de Artola, spokesman for the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC).
According to a risk report from the European Center for Disease Control and Prevention, nearly half of the genetic tests for influenza virus uploaded from Europe to GISAID – a huge database with sequencing results – are subclass K. There is no published data on its presence in Spain.
Is the new form of the virus more dangerous?
It is a matter under investigation and there are no clear conclusions on it. But even if that’s not the case, and the individual risk of developing a serious case is not greater, the emergence of a different virus tends to cause larger, more intense waves — with more people infected, even if they are mild — and could also explain why it arrives earlier.
“If the H3N2 virus has spread less in recent years, the population has had less contact with it and thus lost their natural immunity,” says Gregorio Montes Salas, Secretary General of the Spanish Society of Preventive Medicine, Public Health and Health Management (SEMPSPGS). “If, in addition, it suffers from mutations, the antibodies will recognize it less well.”
“Although the individual risk of severe disease may be similar to that in previous years, a larger epidemic, driven by reduced immunity to infection, may cause the absolute number of hospitalizations to rise,” the European Center for Disease Control and Prevention warned.
Does he escape vaccines?
As with natural immunity, immunity achieved with vaccines is likely to be somewhat less effective against a new form of the virus. This was indicated by the first research conducted by the European Center for Disease Control and Prevention on rodents. At this point, it must be taken into account that the vaccines presented today were produced based on viruses circulating a few months ago in the Southern Hemisphere, before the emergence of subcategory K.
However, experts insist that vaccines continue to provide protection where it matters most. “If we had more immunity, we would avoid more infections,” says García Martínez de Artola. “But, even if this is somewhat less, we will develop fewer serious cases, and there will be fewer hospitalizations and deaths. There may be more cases, but in general they will be milder.”
When did you start in Spain?
Although there are slight differences between communities, the change in trend was observed in Catalonia at the end of October. “It was in week 43 (from 20 to 26 of that month), when the first change in last year was not noticed until day 45 and cases started to rise strongly in month 48. We are now in week 47 and there have been four weeks of increase,” explains Esteve Fernandez. The Basque Country also noted an increase in hospitalizations on those dates.
In the latest available report from the Surveillance System for Acute Respiratory Infections (SIVIRA). In addition to diagnosing influenza syndrome and estimating the infection rate, positivity – the proportion of tests on patients with compatible symptoms who ultimately test positive – is also rising sharply and is 21.6%, up five points from last week. Hospitalizations continue to rise and now stand at 2.6 cases per 100,000 people.
What do the authorities recommend?
The message is unanimous: People who are part of risk groups and have not yet done so should run and get vaccinated. Most societies have taken measures to facilitate this. The influenza vaccine is recommended for all people over 60 years of age, pregnant women, children six months to five years old (more in some communities), and patients with certain diseases. The same goes for health care workers, a group of which only 39.5% were vaccinated last year. The first data provided by local communities, which is still provisional, this year indicates an improvement in coverage in all categories.
High infection rates have also led Galicia and Aragon to recommend and make the wearing of masks mandatory, respectively, in health centres, even when symptoms do not appear.
When will the peak be reached?
The peak of influenza in Spain usually occurs at the end of January or beginning of February. All predictions are that it will be introduced this year and will be reached – the week may not be the same depending on the community – sometime between mid-December and early January. Catalonia awaits you between the second and third week of December. However, sources consulted in other communities fear that it will be a little late, in the middle of the Christmas holidays, which could give a final boost to infection numbers.