The Covid-19, a distant memory? Some thought so. Unfortunately, in the middle of summer, the epidemic that we wanted to forget broke out during the five days of the 2023 edition of the Bayonne Festival. In the pharmacies of the region, between 70 and 90% of the tests turned out to be positive, observe South West And France Blue.
Nationwide, cases are also on the rise. In its weekly monitoring point dated August 1, Santé Publique France evokes an “increase” in emergency room visits and hospitalizations, “in small numbers”, for suspected Covid-19 infection from July 24 to 30: + 26% or +149 passages compared to the previous week. This increase concerns “all age groups and in particular among adults”. But it still remains low, far from the levels seen over the past three years.
The epidemic is also starting again in the United Kingdom. According to Christina Pagel, professor of operations research at University College London, Covid-19 infections could continue to increase in the autumn, when the return to school and work. “We could see the wave continue to grow, and grow faster, in September,” she says. at the Guardian.
Joined by L’Express, Antoine Flahault, epidemiologist and director of the Global Health Institute at the Unige Faculty of Medicine also believes that “there is every reason to think that Covid-19 will return this fall and this winter in the northern hemisphere”. He explains: “It did not stop circulating in the southern hemisphere throughout our summer (their winter). It even caused a fairly strong resurgence in Japan in July, especially on the island of Okinawa.”
A triple epidemic in winter?
Several factors can explain this increase in detected cases: decreasing immunity, the appearance of new variants as well as meteorological factors such as bad weather which encourages the population to stay indoors.
“Immune evasion mutations continue to emerge and cross-protection looks increasingly precarious. Meanwhile, immunity beyond one year declines markedly,” explains the Guardian Professor Danny Altmann, immunologist at Imperial College London.
“There is no need for a drop in immunity to explain the resurgences that we have experienced with Omicron since the end of 2021,” said Antoine Flahault. “On the other hand, vaccine and hybrid immunity (also conferred by previous infections), if it does not protect us well against new infections, is effective against severe forms of Covid.”
In the northern hemisphere, last winter was marked by a triple epidemic (Covid-19, influenza and RSV). Experts fear a similar situation this winter. “What worries me the most is if we get a repeat of the last winter slump in the NHS (Editor’s note: National Health Servicethe public health system in the UK) this winter, with Covid, influenza and RSV all hitting around the same time,” says Christina Pagel.
Antoine Flahault is more cautious. “We do not know how to predict epidemics in the long and even medium terms”, recalls the epidemiologist. It is not impossible that the climatic phenomenon El Niño enters the equation. “Work that we had carried out in my team several years ago indicated that El Niño, which we are currently experiencing, is not favorable to influenza epidemics and therefore to the transmission of respiratory viruses”, he indicates. If, “statistically the epidemics are less strong and less deadly during these periods”, on the other hand El Niño “is more conducive to the circulation of other diseases, in particular transmitted by mosquitoes in certain places of the globe.”
A lack of data
Christina Pagel is worried about advancing “almost blindly”. Blame it on the lack of available data on the epidemic. While the UK Health Security Agency (UKHSA) continues to track certain data on Covid-19, such as the number of hospitalizations, many surveillance studies on infection levels have been completed. In England and Wales, wastewater monitoring programs have been canceled, as experts deplore.
Antoine Flahault also defends this indicator which “allows the monitoring of respiratory viruses, influenza, Covid, RSV, as well as the arrival of new variants, at a lower cost”. “It is an epidemiological instrument of choice that must be spread quickly throughout Europe and made available to epidemiologists”, he underlines. In order to “end these recurring epidemics of respiratory virus diseases”, the epidemiologist also recommends working on improving indoor air quality which should be “a priority for all premises open to the public, starting with schools, hospitals and nursing homes, starting this winter.”
“We of course have some predictability on seasonal flu because we have the data for many years. However, with Covid, now that we no longer have these multiple streams of data to draw on, it is more difficult to say what’s going on [dans la population générale]”, declares at the Guardian Professor Rowland Kao, epidemiologist at the University of Edinburgh.
In the United States, where the epidemic is also on the rise – 8,000 hospital admissions for Covid-19 in the week ending July 22, an increase of 12% compared to the previous week – experts also warn about the lack of data available to them. As related the washington post, the Biden administration stopped sending free test kits to households last June. Those that Americans have accumulated over the past year and a half are expiring.
“Eris” this new variant that spreads
“We will continue to see people hospitalized with Covid-19 for diseases that could have been prevented if the tests had been freely and widely available”, regrets to the American daily William Schaffner, professor of medicine specializing in infectious diseases at Vanderbilt University Medical Center.
In the United States, the federal authorities are preparing an autumn recall campaign using a new formula adapted to the XBB variants which have dominated throughout the year. The new Pfizer vaccine targeting the Omicron XBB.1.5 subvariant could be authorized very soon in the United States, even if it is no longer the majority in the country. According to Professor Danny Altmann, an immunologist at Imperial College London, it is important to plan a series of boosters and work out which specific vaccine this should involve.
Especially since a new variant is breaking out. According to the open access data platform GISAID, the EG.5 strain, nicknamed “Eris”, would now be the majority in France. It is present in some 35% of scans, more than any other variant, reports a graph from GISAID posted on Twitter.
The British health security agency estimated on July 20 that nearly 15% of cases in the United Kingdom were also caused by this strain, increasing by more than 20% per week, according to Forbes. The situation is the same in the United States, where this variant was the source of 17% of contaminations on August 5, against 12% two weeks earlier. “It could well supplant the previous XBB variants which have been leading the race since the end of winter”, confirms Antoine Flahault.