Virologist Louis Kroes of the LUMC. (Photo: ANP).
Leiden, April 16, 2022, 13:23 hrs by the editors
Although spring has been in full swing for a few weeks and cold winter days have given way to warm spring sun, a remarkably late flu wave is sweeping the country. After two years of absence due to corona measures, the influenza virus is now catching up. “We are now getting a taste of this,” says virologist Louis Kroes of the Leiden University Medical Center (LUMC).
According to Kroes, it is remarkable that the influenza virus is still around, because it thrives better in the cold winter when people spend a lot of time indoors and close to each other. “That is usually less by this time. That is also a limitation that ensures that this wave will not be very bad. Influenza is often absent in the summer months,” he tells media partner Omroep West.
According to Kroes, the fact that the virus is now spreading has to do with the reduced immunity because the virus has not been able to circulate among the population for two years. “Because the virus has not circulated, immunity is declining, especially in those who have health problems, for example. They can become seriously ill with all kinds of complications.”
No drastic changes
Just like the coronavirus, the flu virus also mutates regularly. Due to the lack of data from the past two years, it is not certain how the virus has developed since before the corona crisis. This can have consequences for immunity and how sick someone becomes from an infection.
“Influenza tends to constantly vary the antigens that determine immunity,” explains virologist Louis Kroes. “There are small changes from year to year, but sometimes they are bigger. That is a situation that we have known for a long time and that has also caused the necessary health care burden for years.”
Fortunately, according to the virologist, it seems that the influenza virus has gone through ‘no drastic changes’. According to him, it is therefore not necessary that people are now going to get a flu shot en masse, because this spring wave seems to be not too bad. “But: the infections that are taking place now can improve immunity in the autumn.”
Difficult to estimate autumn
Kroes warns that illness caused by the flu can still have a significant impact, both on the person himself and on society. “Immunity through vaccinations is of course the best, because then you don’t have to deal with the disease.”
“We are curious how the virus will develop. When there is no longer any corona restrictions, influenza can also run its course. The fact is that they will both return this fall and it is difficult to estimate whether that will be serious,” Kroes warns. “But unless crazy variants show up, I don’t think we should be gloomy with the immunity we’ve built up.”
What helps is the amount of knowledge that is already available about the influenza virus. “Of course we have known it for much longer than the corona virus, so we are better prepared than we were during the corona crisis. The vaccination has been available for some time and is well organised. The antivirals have also already been developed and available in specific cases. Vaccination of risk groups was already well established.”
Leiden Science