The flu returns out of season. Increase in cases indicates virus circulation in spring

With spring fast approaching, Portugal could be entering an “off-season” seasonal flu epidemic, with the increase in flu cases in recent weeks following the more usual winter pattern. The status is established at Sunrise by Ana Paula Rodrigues, head of respiratory virus surveillance at the National Institute of Health Dr. Ricardo Jorge, who explains, alongside what is happening in other European countries, the lifting of pandemic restrictions and the drop in immunity because there has been little exposure to influenza since 2020.

After last week an influenza A epidemic was detected in Leiria, with 65 confirmed cases, especially among young people, INSA, which monitors influenza activity in the country, revealed this Thursday that in the first week of In March, hospitals reported a total of 165 cases, all type A, and there were no flu patients requiring intensive care, information hospitals report to the institute weekly.

Ana Paula Rodrigues explains, however, that the circulating type A viruses, namely A(H3), which is generally associated with more severe influenza seasons and which has dominated unrecognized infections, show differences from those used in the production. flu shots given last fall. This is an expected evolution of viruses and drives the annual flu vaccine update, but with increasing circulation of the flu ahead of new vaccines, it should drive more precautions, especially by the most vulnerable population.

“We saw a slightly different pattern than what we were used to before the pandemic compared to the flu, but this is not very surprising given the changes in recent years,” notes Ana Paula Rodrigues, noting that in March the usual was coming out of the flu season. “With the measures in place for covid-19, we were virtually flu-free for two years, even though the virus was circulating. Now we have a loosening of restrictions and there has been a decrease in the average temperature. All of this combined can lead to the situation we are witnessing,” continues the doctor. “What we have seen over the past three weeks is a gradual increase in the number of cases, especially in hospitals, which makes us think that in the coming weeks we could be entering a flu epidemic. For the moment, the activity will not be very intense because we have not seen any patients hospitalized in intensive care and all-cause mortality has been within normal values, but it is a situation that we are monitoring, ”guarantees the responsible.

Most likely co-infections

At a time when covid-19 cases are also on the rise again, with a 35% increase in the last seven days and what seems to be a sixth wave to form, Ana Paula Rodrigues admits that it is expected that , in this scenario, more cases of co-infection with SARS-CoV-2 and influenza will occur, as the country faces for the first time what is expected in the coming winters: the coexistence of covid and influenza, in addition to other viruses. , which circulate more in cold weather.

Already called ‘flurona’, until March 6, 33 cases of co-infection by the influenza virus and SARS-CoV-2 have been reported to INSA. Ana Paula Rodrigues says that there is currently no national analysis on the clinical manifestations of these cases, which will now be evaluated because there are a greater number of cases. “It is an analysis that is also being done at European level to understand whether or not these are more serious cases than the others. In some countries that had more influenza at the start of the pandemic in March 2020, the first co-infections were reported, but there were few cases. If it is confirmed that we have entered an influenza epidemic, these situations could be more frequent and will have to be studied”.

Stronger flu alert

Immediately, the fact that the A(H3) virus dominates the rise in influenza cases indicates that stronger influenza may occur. “In influenza A, there is the A(H1) virus and the A(H3) virus. Right now what we have predominately is A(H3), which according to our history, in years when there are more serious infections, especially in the elderly and more vulnerable, with an impact on the mortality and hospitalizations. That’s not to say that will be the case this year, but it’s important to get the message across that although we are in a situation of easing covid-19 restrictions, there are measures such as hand washing , respiratory etiquette and care for increasingly sick older people, especially if you have symptoms, which must be maintained during this period”, recommends Ana Paula Rodrigues.

The fact that the circulating type A viruses, already characterized by INSA, are genetically different from those used in vaccines for the 2021/2022 season, leads the official to reinforce the alert, highlighting the role of so-called non-viruses. pharmacological. measures, as if seen in covid-19, in the smallest transmission. As to whether an influenza epidemic in the spring could motivate the maintenance of measures such as wearing a mask indoors, which the DGS has indicated will be lifted in April, Ana Paula Rodrigues pleads that more than an obligation, there must be a recommendation for the use of wearing a mask when you have symptoms, as well as measures such as avoiding exposure of the most vulnerable people or avoiding large gatherings of people .

at the birth of sOL pulmonologist Filipe Froes stresses that the appearance of more flu cases is expected with the easing of restrictions, stressing that developments must be monitored to understand the impact. In the event of co-infections, one of the data already available is that being vaccinated against at least covid-19 is a protective factor, he reinforces.

Starting from the principle that with the onset of hot weather, the incidence could slow down, the doctor believes that the current situation should lead to a strengthening of awareness of the measures to be adopted, the importance of vaccination against covid-19 and flu to prevent serious illness. “This situation warns us that next year we will probably have the flu we had before the pandemic or stronger, with the disadvantage of having more fragile people because they have not had contact with the virus in recent years. years and are in poorer condition. immune response. . We will have to try to vaccinate the most vulnerable people against the flu and with more effective vaccines”, he underlines.

In the week when the DGS announced the end of the daily covid-19 bulletins, the doctor defends the importance of maintaining strong surveillance to understand as soon as possible if the increase in incidence translates into an increase in complications and hospitalizations in hospitals, which tend to appear with a greater lag._“I don’t know if it was the best time for the Directorate General for Health to change the model for publishing information. It is something that, in times of increased incidence, can condition us in assessing and preparing for response,” he says.

Questioned by the Birth of SUN This week, the DGS did not provide an update on the increase in covid-19 cases, which now have a weekly report on Fridays, and the evolution of the flu. At the last Infarmed meeting, a new respiratory virus surveillance model was presented by INSA, which will be monitored simultaneously, based on the contributions of doctors, hospitals, laboratories, not only of influenza but of the covid-19 and respiratory syncytial virus, extending the surveillance of influenza which began to be practiced in the country in 1990 and which since 2008 has information provided by a sentinel network of doctors. Ana Paula Rodrigues moves to Nascer do SUN that the new system is being assembled, with a pilot planned for the summer, underscoring that it will be a model for a more stable phase of the pandemic.

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