The invisible pandemic

Everyone will be exposed to the Severe Acute Respiratory Syndrome (SARS) coronavirus 2, and most people will be infected. Johan Giesecke, the epidemiologist behind Sweden's non-containment strategy, explains in an article published in the medical journal The Lancet the value of choosing herd immunity in his country. He argues for the implementation of an "optimal care" strategy for the most seriously infected people. A strategy that contrasts with the containment strategy adopted by most other countries.

" About 30% of the people in Stockholm have reached a level of immunity. We could achieve herd immunity in the capital as early as next month." This is what Karin Ulrika Olofsdotter, Sweden's ambassador to the United States,says . Epidemiologists explain that herd immunity is reached when two-thirds of the population has been in contact with the virus. This would be the way to extinguish the epidemic. A choice adopted by the Swedish government, breaking with the containment measures taken by most other countries.

Johan Giesecke, a former state epidemiologist in Sweden from 1995 to 2005 and currently a member of the Strategic and Technical Advisory Group on Infectious Risks (STAG-IH) of the World Health Organization (WHO), also says that herd immunity will be achieved as early as May in Stockholm and its region. This would be a performance compared to the results of neighbouring countries that have opted for containment. The Pasteur Institute estimates that by May 11, on average, only 6% of the French population will have been in contact with the virus.

Sweden put their faith in the Swedes

Sweden surprised the world by opting for a strategy of trusting its inhabitants to spontaneously respect social distancing measures and impose some restrictions on themselves (prohibition of gatherings of more than 50 people, visits to retirement homes and closure of high schools and universities). No confinement in Sweden, bars and restaurants remained open, hairdressers, cinemas, theatres, gymnasiums and parks, as did most businesses and services. Sweden continued to live almost normally during the epidemic.

Result? The country of 10 million inhabitants records a little more than 2,700 deaths, mainly in the county of the capital Stockholm. This figure is much higher than that of its immediate neighbours such as Denmark, Finland or Norway, confined countries that have only recorded a few hundred deaths. But Sweden's death rate is still lower than that of countries such as the United Kingdom, Spain or Belgium. And its economy has never come to a standstill.

In an article published May 5 in the medical journal The Lancet, Johan Giesecke notes that PCR tests performed on half a million people in Stockholm county as of April 29 show that between 20 and 25 percent of the population is infected with the virus. According to the epidemiologist, " 98-99 percent of these people probably do not know, or are not sure, that they have had the infection; they either had severe symptoms but not severe enough to go to the hospital and get tested, or no symptoms at all. Serological tests now confirm these hypotheses. ".

This observation leads the epidemiologist to state: Everyone will be exposed to coronavirus 2 of a severe acute respiratory syndrome, and most people will be infected."Everyone in the world.

A low noise running light

The doctor goes on to explain that, in his opinion, " COVID-19 is spreading like wildfire in every country, but we don't see it - it's almost always spreading from young people who have no symptoms or mild symptoms to others who will also have mild symptoms. This is the real pandemic, but it is continuing below the surface and probably reaching its peak in many European countries. "

A low-noise circulation of the virus against which " there's not much we can do [to prevent its spread]: a blockade could delay severe cases for a while, but once the restrictions are relaxed, cases will reappear."

Johan Giesecke confirms that this spread of the virus is independent of any containment measures. " I think that when we count the number of deaths due to COVID-19 in each country in a year's time, the numbers will be similar, whatever measures are taken, "

According to him, the countries imposed strict containment because everyone followed the others; as in a kind of panurgism. In an interview with the Argentinian daily Infobae, he considers that " for politicians, it is important to show strength and action ". But in reality, he observes, " for politicians, it is important to show strength and actioncthere is no scientific proof for most of the restrictions that countries take... There are some things that we know scientifically, like washing our hands is good. We've known that for 150 years. We also know that we have to maintain a certain social distance, that is, not get too close to others. But the rest? No one knows whether closing schools will have an effect. The same goes for closing borders, or banning people from being outside. ".

This specialist would like to point out that " measures to flatten the curve may have an effect, but a lockdown only pushes serious cases into the future - it won't prevent them. Containment measures serve a different purpose than stopping the spread of the epidemic," he says. They are mainly intended to buy time to decongest emergency services, wait for the first effective drugs and vaccines to be developed. On the latter point, however, he is sceptical: " It will take time to develop them and, given the lack of clarity in the protective immunological response to infection, it is not clear that vaccines are very effective. "

A strategy based on "optimal care".

In summary, says the epidemiologist, COVID-19 is a highly infectious disease that spreads rapidly in society. It is often symptomless and may go unnoticed, but it also causes serious illness and even death in some populations. According to him, the most important task of the health services " is not to stop the spread, which is practically useless, " but to focus on providing " optimal care " to those who are seriously infected.

The wager on herd immunity still rests on a foundation of uncertainty. herd immunity has been presented as the most effective way to stop an epidemic in the absence of a vaccine. For the coronavirus responsible for COVID-19, experts estimate that herd immunity is achieved when two-thirds of the population has been infected. If they survive the disease, they develop antibodies that immunize them. The virus then disappears from circulation for lack of sufficient hosts.

However, the problem with Covid-19 is that the duration of this immunity is unknown. Is it lifelong, as with some diseases, or does it only last a few days. The WHO said in an April 24 statement : " No studies have evaluated whether antibodies to Sars-Cov-2 confer immunity to a new infection of this virus in humans. " The international organization said it " expects most people infected with Covid-19 to develop an antibody response that will provide some level of protection. " But of what kind and for how long?

Header picture: Johan Giesecke, photo Stefan Nilsson