Cases of flu have been rising in France in recent weeks, in what health authorities are calling a “second epidemic wave” after the first peak at the end of 2021. It comes as Covid cases also rise.
In its latest weekly update, health authority Santé publique France (SPF) stated: “After a first epidemic wave from December 20-26, 2021, Île-de-France had moved to a post-epidemic level by January 17-23, and moved back to an epidemic level from March 7-13.”
Despite rising cases, this year has so far seen relatively low numbers of people requiring hospitalisation or intensive care admissions, when compared to the flu epidemic spikes of 2017-18, and 2018-19.
Cases were considerably low in 2019-20, and there were even fewer in 2020-21, due to the Covid pandemic.
Rising cases this year have been blamed on factors including a drop in barrier gestures, and the return to school.
Drop in barrier gestures
Dr Jérôme Marty, a GP and president of l'Union Française pour une Médecine Libre, said that this increase in the number of cases is due to the relaxation of barrier measures following the lifting of health restrictions.
He told BFMTV: "We haven't had, or hardly had, a flu epidemic in almost two years due to masks and hand washing. [But] obviously people are relaxing [on rules], and this has led to the re-acceleration of the flu epidemic.”
SPF appears to agree, stating that the intensification of the flu epidemic is partly due to "the current easing of control measures for the Covid-19 pandemic".
Negative effect of back to school
This increase in flu cases was also "caused by the end of the winter school holidays in all regions", SPF said.
It wrote that the mixing of schoolchildren at school is known to be a vector for the spread of diseases, and that increase in the number of flu cases followed the starts of the school year in February, depending on the holiday area.
Infectiologist Dr Benjamin Davido said: "I already said that there would be a risk of a restart of Covid-19 with the start of the school year, and we are seeing the same thing with the flu.”
Those most at risk of severe influenza are thought to have lower immunity this year than in previous, pre-Covid years, due to lockdowns, and having little-to-no exposure last year.
Professor Bruno Lina, virologist and member of government advisory group Le Parisien, said that despite a call being issued for a joint Covid-19 and flu vaccine, takeup rates were low.
He said: “The further away from the vaccination, the more we lose ‘vaccine effectiveness’.”
SPF said: “The first estimates of the real-life effectiveness of [this year’s] flu vaccine will be communicated as soon as they are available",
Rising cases of flu have come at a time when Covid-19 cases have also started to rise, and the coexistence of the two viruses could work against them, said Dr Davido.
He said: "Viruses have a hard time coexisting at the same time, so it's possible that it's competing with Covid-19. With the virus being less prevalent, it gives flu a chance to recirculate and we are seeing the start of a real flu epidemic.”
A short-term spike in cases?
Experts have also suggested that this spike in cases could be short-lived, as it is “late compared to previous years”, and happening as spring is arriving.
Better weather usually means that respiratory viruses spread less.
Similarly, referring to Covid, Health Minister Olivier Véran said on Wednesday 16 that cases were also likely to "rise for 10 to 15 days probably, until the end of March, and then we expect there to be a decrease".
In its update, Santé publique France added that methods to protect oneself from flu are similar to those used to stop the spread of Covid. It said: “It is important to remember that systematic adoption of barrier measures and influenza vaccination is an effective means [of stopping the virus].”