Karine Lacombe
  • The Conversation

Covid: "We have moved from an epidemic to an endemic situation"

The Covid epidemic has disappeared from the media in France, but not from the population. What is the situation in hospitals? And what about the vulnerable people who continue to be affected? Prof. Karine Lacombe, infectious diseases specialist and Head of the Infectious and Tropical Diseases Department (Hôpital Saint-Antoine, Paris), assesses the situation based on available data.

The Conversation-France: Covid, of which all variants are now considered as sub-variants of Omicron, seems to be "out of fashion" in the news. Is there really nothing more to say?

Karine Lacombe:

You can't say that. Even if the Covid epidemic no longer has its past impact, we are currently in an epidemic recovery, as the latest figures from Santé publique France show. For the moment, there is no real impact on the health system, because for several months we have had a decrease in the number of people who present severe forms of the disease and who must be hospitalized.

But we continue to see people who have so-called "secondary" Covid, that is to say, who are hospitalized for something else and who are discovered to be infected during the automatic screening measures that we carry out.

And there are always severe forms that come to us, particularly from people who are immunocompromised or who have not received any vaccinations and have never been infected. Even though this is a pandemic with a very large spread of the virus in the population, there are still people out there.

There is now real evidence that vaccination has had a very significant impact on the epidemic dynamics, with global immunization being enhanced by exposure to the virus itself. Vaccinated people who have been in contact with the virus have developed good immune responses, which constitutes a kind of barrier not to the diffusion of the virus (because the latter has acquired many mutations that allow it to escape in part from the immune defenses) but against the severe forms.

T.C.-Fr.: Last year, you told us that we were in the process of leaving the "Covid exceptionality". Is this exit confirmed, and what are the consequences?

K.L.: After three years of evolution, we are now in an endemic situation and no longer in an epidemic situation. With a virus that may become seasonal, it is still a bit early to say because we continue to have successive waves during the year.

However, the waves as such, these breakers that we knew at the beginning, do not exist anymore: they are more like wavelets, which arrive continuously. Because we have a virus that continues to spread actively in the general population.

In other words, we are going through an epidemiological transition: from an epidemic stage to an endemic stage, with a respiratory virus for which we are the reservoir, which is transmitted from person to person and which evolves... like all other viruses of this type. Covid has become just another pathology to manage.

It is a virus that we have learned to live with.

T.C.-Fr.: If it circulates less, the virus, whatever the derivative of Omicron considered, still circulates. What are the consequences for the people affected?

K.L. : The forms that are currently circulating pose major problems for us in terms of treatment, because monoclonal antibodies such as Evusheld are no longer effective against them. So immunocompromised people, who could previously be protected by prophylaxis (to prevent the onset, development or worsening of a disease) with an injection of these molecules, are now vulnerable again.

We therefore have a rather reduced therapeutic arsenal, with direct antivirals such as Remdesivir or Paxlovid.

On the other hand, we are using again a monoclonal antibody that we used last year but then discarded because of its lower efficacy compared to Evusheld in terms of virus neutralization: Sotrovimab. We are using it again, but at higher doses and in patients who do not need oxygen - so at a very early stage.

Monoclonal antibodies have been used for a long time against the Omicron variants of SARS-CoV-2 and are now ineffective. Sotrovimab is the last one still active.

The fact that it is falling in the general population means that the importance of the epidemic and the circulation of the virus is minimized, because we no longer have as much data. It's a choice that we made in order to return to a normal life, where we don't spend our time getting tested... But it has a negative impact on our knowledge of the situation.

So when you see an epidemic recovery like the one that's going on now, you have to think that it's actually much bigger than what's reported in the numbers—because people are not getting tested anymore.

For immunocompromised people, but also for the very elderly population, who have pathologies predisposing to severe forms of the disease (and for people living in contact with them), it is important to continue to be screened - and to wear a mask if you are positive if you are in contact with this vulnerable group: this is what allows you to be treated early on if necessary.

Similarly, there is not much talk about vaccination anymore. However, new booster campaigns will probably have to be launched. The people who will be the most concerned are, without surprise, those whose immune defenses decline the fastest: the elderly, people predisposed to severe forms of the disease (overweight, hypertension, renal, cardiac or pulmonary insufficiency, etc.), immunocompromised people...

T.C.-Fr.: Has France learned any lessons from the past years? What, in concrete terms, should be developed?

K.L.: Investment in fundamental, clinical and epidemiological research is essential. Whether it is to find new treatments, to provide the country with surveillance means to quickly identify the appearance of any new variant - for this, we need high-speed sequencing means.

We must also be able to organize ourselves better, and think now that we are in a post-crisis period (at least in an inter-crisis period) about how to better organize our health care system so that we can be better, more reactive, and more relevant if we have to deal with a new wave - either of a new variant or of a new virus.

While there are many things underway at the hospital level, at the ambulatory level (outside the hospital), it is still complicated. And the interface between hospital medicine and ambulatory medicine has not yet found its optimal mode of operation. There are things to find in terms of organization of care.

Perhaps we can look at certain initiatives taken elsewhere? In the United States, for example, once a Covid test is positive, the pharmacist checks the indications for the patient, the drug interactions with his or her background treatment(s) and can deliver a treatment. Without having to go through a doctor.

T.C.-Fr.: You say that the hospital has already taken certain measures. What are they, for example?

K.L.: This winter has been much quieter as far as Covid is concerned... we've been pushed around more by the flu and bronchiolitis. But, at the hospital level, we have been quite reactive and have reactivated our crisis cells: structures put in place at the time of the big Covid waves. This allows us to better organize care, at least within the hospital. But in terms of treatment, there is still a lot of progress to be made against both the flu virus and RSV (respiratory syncytial virus), which causes bronchiolitis.

In addition, we have developed multiplex analysis techniques: this allows us to diagnose better and faster - series of 15 to 20 different viruses for example. This is how we saw that there were a lot of RSV-flu, RSV-Covid, flu-Covid, rhinovirus-flu coinfections... in the middle of this whole soup of winter respiratory viruses.

These co-infections do not really change the management, which is mostly symptomatic for this kind of virus. But as they are often elderly people, or with co-morbidities, this requires quite long hospitalizations. With RSV, sometimes it takes two-three weeks for patients to go without oxygen.

There are simple reasons why the epidemics have been so strong this year. RSV is seasonal (from the beginning of winter) and it is transmitted by hands and air: hands are washed less than during the first two years of the pandemic... And masks are no longer used. There is no surprise.

Moreover, it is a virus that induces weak immune defenses and that lasts a short time. The fact that we haven't had RSV in the last two years may be correlated to the fact that we have poorer immune defenses—that we inherit the contaminations of previous years.

Same thing for the flu. In addition, vaccination has been particularly low, even among doctors. It is difficult to explain why, because there is no particular reluctance to undergo it. Should we see a certain fatigue in this?

T.C.-Fr.: Is there any prospect of "getting out" of Covid?

K.L.: The WHO gives a start date to a pandemic, not necessarily an end date... In fact, it depends on the type of epidemic. For Ebola, for example, there is an end date. But for Covid, which has now reached the endemic stage and is therefore present everywhere and at a low level, it is more complicated.

However, the WHO may soon lift the state of health emergency at the global level, even though there are still many cases. Its Covid-19 emergency committee will hold its next meeting in April, so watch for announcements.

Karine Lacombe, Infectiologist, Head of the Infectious Diseases Department at Saint-Antoine Hospital, Sorbonne University

This article is republished from The Conversation under a Creative Commons license. Read the original article in French.

The Conversation