What’s behind the latest surge in Covid-19 cases?

Staff attend to a Covid patient at Lausanne University Hospital (CHUV) on January 11, 2022. © Keystone / Gaetan Bally

Covid case rates are rising again across much of the Western world in countries like France, Germany, Italy, Britain and Switzerland, but also in Asia. SWI swissinfo.ch talked to a Geneva-based Covid expert about what’s behind the dramatic resurgence and how concerned we should be.

Confirmed cases of the virus had been falling steadily worldwide since January but rose again last week. Switzerland lifted almost all of its Covid-19 pandemic restrictions on February 17 but the country continues to experience high daily infection figures. After falling steadily from a peak in late January, the number of new cases started rising again from mid-February.

SWI swissinfo.ch: Last week the World Health Organization (WHO) warned that the end of the Covid-19 pandemic was a long way off, adding that the new cases are just the “tip of the iceberg”. What’s your view on the recent surge?

Antoine Flahaut, director of the Institute of Global Health at the University of Geneva. Antoine Flahault

Antoine Flahault: After each Covid wave, politicians, journalists, the public, but also many experts want to see it as the last. Now we have the Omicron wave, and again they are saying, “it’s finished”, but it’s not.

Antoine Flahault

Antoine Flahault has a degree in medicine from the Université Paris Descartes and a doctorate in medical sciences in 1991 from the Université Paris Diderot.  

He is currently director of the Institute of Global Health at the University of Geneva.  He is also president of the newly-founded Agency for Public Health Education Accreditation in Brussels, and co-president of the European Academic Global Health Alliance.

His work has focused on surveillance of infectious diseases, and he has played leading roles in setting up a national disease surveillance system in France (Réseau Sentinelles) and in coordinating a task force against dengue fever in the French West Indies and against Chikungunya virus in the Indian Ocean region.

We are currently experiencing a big rise in cases. In Switzerland, the incidence level is high [On March 23 the 14-day incidence rate was 4,087 cases per 100,000 residents, among the highest in Europe]. We have reached the same levels of hospital admissions as for the Delta variant and the BA.1 Omicron variant. But we are just more used to it.

We have to acknowledge at least that people in European countries are not suffering from severe complications like in Hong Kong or South Korea. So it seems that this wave, at least for the moment, is not as severe in Europe as in some other parts of the world such as in southeast Asia.

Nonetheless, mortality rates remain high in most European countries; mortality due to Covid ranks first among all causes of mortality. This is not acceptable. We are facing a completely new pattern of mortality and we seem to accept it while we could be trying to address it more effectively.

SWI: What’s behind this new increase in infections? Some blame governments relaxing public health restrictions, but isn’t it simply the new BA.2 Omicron subvariant, which is estimated to be about 30% more contagious than its predecessor BA.1?

A.F.: It’s a good question. An initial reaction would be to say the rise is due to lifting prevention measures too early, as was the case in Switzerland or the Netherlands. But some countries, like Italy or France, have not lifted measures and they are experiencing the same upturn. I would say it’s probably not completely the lifting of measures that explains this rebound.

My hypothesis is about outdoor air pollution. We worked at the University of Geneva with climatologists on a research paperExternal link that shows that peaks of air pollution in winter and fine particles are associated with a peak of Covid-19 a couple of weeks later. In recent months we have seen very mild weather in Europe associated with high levels of fine particle pollution, which could have triggered such an upturn.

SWI: Should we be worried by the recent rise in infections?

A.F.: Our experience from the past two years tells us that we should always be worried with Covid-19. It’s not the flu. It’s not a cold. It’s a disease that may lead to hospitalisations and deaths, and also Long Covid. So, we need to be worried and protect those who are at higher risk of these complications.

We have also learned that many people do not experience severe illness with Covid-19. Many think that it’s not such a big issue and they are not very worried. But if they want to be empathetic and have solidarity with those who are at risk, they should be protecting themselves and those who are more vulnerable.

The viral load is really important in determining how severe the infection is. When you are at risk, if you do not get contaminated with a high viral load you experience a much less severe form of Covid-19. Wearing a mask, for instance, decreases the viral load significantly.

SWI: What’s your view on the current Covid situation in Switzerland (see infobox below)?

A.F.: Any forms of success are always fragile. South Korea has been one of the best-performing countries fighting Covid. Around 87% of the population are vaccinated and 64% have received a booster dose.

They have done very well if you look at their mortality indicators. Mortality due to Covid is much lower in South Korea than in most parts of the world, particularly the Western world. But South Korea is now underperforming. They have one of the highest incidence levels in the world, if not the highest. They have recently experienced a wave of hospitalisations in intensive care units and a big wave of mortality, too. So I would not say too quickly that the Omicron BA.2 subvariant is so mild.

Covid situation in Switzerland – latest update

Coronavirus cases are expected to continue to increase in Switzerland in the coming weeks, driven by the more contagious Omicron BA.2 subvariant, federal health officials reported on March 22. Hospitalisations, intensive care cases and deaths have also increased slightly in recent days. But federal officials on Tuesday did not seem too concerned. “Thanks to the high level of immunity, high numbers of cases can now be allowed without risking the health institutions being overburdened again,” said Patrick Mathys, the head of crisis management at the Federal Office of Public Health (FOPH). 

At the weekend a senior health official expressed concern that the number of new coronavirus cases in Switzerland may be massively underreported. Rudolf Hauri, president of the cantonal health authorities, estimates the number of people newly infected with the virus at 150,000 per day, versus 25,000-30,000 per day officially reported at the moment. He warned that even triple-vaccinated people could become infected and end up in hospital when the virus activity is so high.

At the beginning of April, the last remaining Covid public health measures (masks on public transport) should be lifted. From April, the FOPH will only communicate coronavirus statistics once a week rather than on a daily basis.

The FOPH and the Federal Commission for Vaccination currently do not recommend a second Covid booster jab.

Switzerland is among the European countries that performed the bestExternal link against the pandemic from the beginning. But will it remain so? It’s difficult to say. Some people attribute Switzerland’s success to the Moderna mRNA vaccine, which is the most used in Switzerland. Maybe thanks to the Moderna vaccine Switzerland has managed to limit its hospitalisation rate and deaths.

This may not continue to be true in the coming weeks if immunity wanes in Switzerland. Switzerland is not well protected in terms of [vaccination] coverage (69%); it remains fragile. We always have a risk of switching to the South Korean example with a high level of contamination accompanied by a high level of hospitalisations and deaths. I will never take this pandemic for granted.