Far from the fear of the early days of the pandemic, which began four years ago, Covid-19 has become commonplace after becoming less dangerous. But it remains an important public health problem, with persistent specificities compared to other diseases.
Standardization is accelerating
The year 2023 marked a new stage in the normalization of Covid. Already sensitive the previous year, after 2020-2021 dominated by a pandemic with historic effects, the trend accelerated.
Since May, the World Health Organization (WHO) has no longer considered Covid to be an international emergency. If the WHO is careful to repeat that the pandemic continues, this decision is a considerable symbol.
The year also saw the end of “zero Covid”. The last major country to apply this exceptional policy, which aims to eliminate the circulation of the disease and not just limit it, China gave it up at the start of the year.
A much less dangerous virus
Why this standardization? Firstly because a Covid infection appears today much less dangerous than in 2020, when many countries decreed unprecedented confinements in the face of the deadly effects of SARS-CoV-2, the virus at the origin of the epidemic.
This is the consequence of effective vaccines, distributed since 2021, and of the immunity acquired by populations over successive waves of virus infections.
Lethality, which corresponds to the individual risk of dying after an infection, “has declined significantly compared to the pre-vaccine era“, emphasizes to AFP Antoine Flahault, epidemiologist at the University of Geneva.
“It’s of the order of one in a thousand or maybe even less, when the risk was counted as a percentage at the start of the pandemic.he emphasizes.
This is a level comparable to an infection with the seasonal flu virus, even if it is risky to precisely designate the more dangerous of the two.
A problem that remains major
Covid has therefore become a respiratory disease among others. But it continues to pose, in this context, major public health problems, sometimes linked to its particularities.
Unlike other diseases such as the flu, Covid experiences several waves per year. It can therefore hardly be described as a winter disease, but an outbreak can coincide with the classic epidemic season.
This is currently the case:Covid-19 is one of the diseases that is progressing at the moment” in many countries, warned Maria Van Kerkhove, epidemiologist at the WHO, on Sunday.
This growth is partly linked to the emergence of a sub-variant, known as JN.1. New version of Omicron, dominant version of the virus for two years, it does not appear particularly dangerous but seems very transmissible.
Contagiousness still high
This is also, generally speaking, the great particularity of Covid compared to other infections such as the flu: it remains very contagious.
“Over the course of a year, 5% to 10% of people catch the flu.“, but much more for Covid, says Mr. Flahault, emphasizing that this mechanically increases mortality at the population level, even if the individual risk is limited.
The precise number of deaths, however, remains unclear because many deaths are linked to the disease without being immediately attributable to it. Official WHO figures suggest some seven million deaths since the start of the epidemic four years ago, but the organization itself admits that the real level is probably around 20 million, or more.
And the long Covid?
Beyond mortality, there remains the question of lasting after-effects, known as “long Covid”: fatigue, breathing difficulties, etc.
The reality of these symptoms is no longer in doubt today, as is their physiological and not psychological origin. However, it remains difficult to establish their frequency and whether Covid causes them more often than other diseases.
The after-effects of the flu, for example, “have not been subject to the same spotlight effect“, underlines Mr. Flahault.
In any case, several studies published this year are rather reassuring in denying the idea of an explosion in cases of long Covid over time.
Conducted among the Swedish population, a study published in September in the Journal of Infectious Diseases thus demonstrates a “lower risk” after an Omicron infection, compared to previous variants.