The report from Jena, Germany, was covered only briefly by the media. No comment from the business world. But what an interdisciplinary team from Jena University Hospital found out in a survey involving 40 long Covid patients  should actually make employers break out in a sweat. The researchers discovered that a SARS-CoV-2 infection substantially diminishes cognitive performance in those affected. Subjects processed visual information more slowly and felt exhausted more quickly than a control group of the same size.

"We interpret this as evidence of chronically diminished brain activity in long Covid, primarily manifesting as slowed information processing," says Kathrin Finke, the psychological director of Jena's post-Covid outpatient clinic. The phenomenon, also known as brain fog, is considered a typical symptom of a coronavirus infection. A meta-analysis of the most common symptoms of post- or long Covid  showed that after an acute infection, an average of 32 percent of all people suffered from concentration disorders and forgetfulness.

The consequences for employers have not yet been fully researched. However, there is growing evidence that long Covid’s effects could have a more lasting impact on the economy than the lockdowns. A virus that slows down cognitive processes, leading to persistently higher absenteeism and increased occupational disability, is a concerning prospect for the business world. Very few companies have publicly taken a clear position on this - not even German car manufacturer Audi, whose former CEO Markus Duesmann was unable to work for months  in 2021 due to his long Covid illness.

For many leaders, the rounds and rounds of sick leave may seem inevitable. But what they fail to recognize is that after four years of Covid-19, they possess the knowledge and resources to safeguard workplaces against the virus. As with many other strategic decisions, this requires a fundamental directive from the top.

237 days of sick leave

At the beginning of the pandemic we often heard the phrase "There is no glory in prevention“. In other words: Because prevention efforts have worked they won’t get any applause. People just stay healthy, and the much-feared wave of infections doesn't even roll in. For the business world, we will have to rewrite this sentence in the future: "There is money in prevention." Companies who invest a medium amount in protective solutions today can save large sums in the long term.

Afshin Gandjour has calculated just how much. In his survey on the economic costs of long Covid in Germany , the professor of health management at Frankfurt School of Finance & Management assumes 84 days of work incapacity per person and a daily production loss of 124 euros (see chart). This results in an annual production loss of 3.4 billion euros for businesses in Germany alone, with additional billions in costs to the health and pension systems. His calculations may even be too low as Gandjour uses data from 2021 and the number of long Covid cases has continually risen since then.

The RWI - Leibniz Institute for Economic Research in Essen, Germany, has more recent data: In an online survey  conducted in June 2022, the more than 1,000 participants who suffered from long Covid reported an average of 237 days of sick leave. The resulting labor loss amounted to 22,200 euros per person. What's more, many of these individuals will no longer be able to work at their previous capacity so that employers will have to replace them. This contributes to the current skilled labor shortage and causes additional recruiting costs.

Another insidious aspect of SARS-CoV-2: As numerous surveys have shown repeatedly , the coronavirus can damage the immune system even in mild acute cases. Although they may have hardly ever been sick in the past, many people who have recovered from the infection will now catch one illness after the other – from cold viruses to strep throat and the flu. This could be a reason for the current extremely high sickness rate which reached a new record level in 2023. A survey by the German Association of Research-Based Pharmaceutical Companies  even revealed that Germany had slipped into recession in 2023 due to the large number of employees on sick leave.

This contributes to the enormously high level of sickness absenteeism. Due to a lack of protective actions, the coronavirus is now spreading unchecked . In mid-December, the Robert Koch Institute's wastewater monitoring  showed the highest level since its start in Germany.

Long after the lockdowns ended, the „immunity debt“ theory was the go-to explanation for constant sickness in large parts of the population. It has since been debunked  because such a concept does not exist in medical science. The term was introduced to the public by a Tokyo reporter for the Wall Street Journal  in 2021.

"An estimated one in ten infections results in post-Covid-19 condition," Tedros Adhanom Ghebreyesus, director-general of the World Health Organization (WHO), stated at a press conference  in April 2023. "Infections", mind you, not "infected people". This suggests that hundreds of millions of people might need long-term treatments. In long Covid research, the disease is now considered a "mass disabling event", triggering a significant global increase in diseases and disabilities.

Many people are contracting Covid-19 two to three times a year now, with some experiencing up to half a dozen infections. And because immunity cannot reliably be achieved through existing vaccines or past infections, we can easily calculate by Ghebreyesus' estimate how many infections it takes until employees are permanently disabled – physically or cognitively.

David Steadson, an Australian epidemiologist living in Sweden, has attempted to model this with data from a US study by the CDC  (see chart). It defines long Covid as "symptoms that last three months or longer and that you did not have before contracting Covid-19". These include tiredness or fatigue, difficulty thinking, concentrating, forgetfulness, or memory problems, difficulty breathing, joint or muscle pain, heart palpitations, chest pain, dizziness, menstrual changes, changes to taste/smell, or inability to exercise. Not included are secondary illnesses that were facilitated by a weakened immune system or organs attacked by the virus.

"Data shows that most people are getting a Covid infection about twice a year", says Steadson who is currently setting up an international Long Covid Resource Center. „So there’s a good chance that within about five years, most people will have contracted a form of Long Covid that affects their daily activities." Although about a third recover within a year, the majority do not according to Steadson. Vaccination seems to decrease the risk, presumably by 15 to 50 percent.

A March 2023 survey by the German Institute for Retirement Provision  should also raise an alarm: 21 percent of people who have at least once been infected with SARS-CoV2 are suffering from post- or long Covid. These are definitely not only vulnerable people. Younger, high-functioning individuals are particularly at risk, with 35 percent of 18- to 29-year-olds and 40 percent of 30- to 39-year-olds affected.

Only some of them will make a full recovery, while most have lasting health limitations. There is still no effective, recognized therapy for long Covid.  Some rehab programmes – sports and activation prescribed against severe post-viral syndromes like ME/CFS  or PEM – can even cause complete occupational disability.

The Swiss cheese system

In the early days of Covid vaccination we believed that the pandemic could be ended by a single intervention: widespread vaccination. This hope has long since faded. As we now know , vaccinations do not provide lasting protection against infection or long Covid. They only reduce the likelihood of infecting others, suffering a severe course of the disease or developing secondary illnesses. The long-held hope in politics and healthcare systems – that vaccinations plus one or two infections would lead to "hybrid immunity" – has also been refuted . Even those who have contracted Covid many times may be infected again and again, with more and more serious consequences for their health.

However, employers can do a lot to minimize infection rate in their workforce, with various interventions working together according to the Swiss cheese model. This visualization  was developed by British psychologist James Reason  and compares safety levels with slices of cheese in a row. The holes in the cheese symbolize the imperfection of those protective measures - the gateways penetrated by the virus. If there is only one slice of cheese – one security layer –, the virus will easily get through. But if other layers are placed behind it with holes in other places, the probability of infection decreases with each additional layer.

The more of the following "slices of cheese" companies will introduce the lower they can keep the infection rate at work. Some of these measures are inexpensive and easy to implement but require more communication and persuasion. Others may be costly but are not dependent on employee participation. Either way, a good information campaign is advisable. After all, employees are not only infected at work but also at home and in their free time. But people familiar with transmission paths and protective measures are less likely to carry the virus into the office or to the workbench.

1. Home office and sickness regulations

It is basically a no-brainer: the more personal interactions people have at their workplace the greater their risk of infection. Before Covid, this applied to colds and other infectious diseases as well. A long-term study by researchers from Constance, Germany,  which has been ongoing since 2020 reaffirms this for Covid-19: Employees who do not work from home bear a significantly higher risk of contracting the virus.

Meetings in particular were found to be a source of infection. For example, 9.9 percent of employees who had taken part in face-to-face meetings since October 2020 had been infected, compared to just 1.2 percent of those who had only met virtually.

Of course, working from home is not an option for many professions. And infections spread outside the company as well. Nevertheless, employers should be flexible with home office politics out of sheer self-interest. Less frequently infected individuals are less likely to be absent and won't carry the virus into the workplace. Should they be infected but don’t have any or just light symptoms, they can work from home while isolated.

But not all employees and employers are handling Covid-19 so responsibly. In a survey conducted by health insurance Pronova BKK in 2022 , nine percent of all respondents said they would go to work with a mild case if they tested positive for the coronavirus. Another eight percent said: "I'll decide depending on what's going on at work." Since the removal of all safety measures, these figures have presumably risen even further.

The infected have the law on their side: Since spring 2023, it is no longer statutory to isolate at home with Covid. What's more, symptom-free infections aren't even considered a case of sickness any more – with unpleasant consequences for sick pay if an infected person stays at home out of consideration for their colleagues. Some employers even pressure their staff to work when infected. The debate is on about whether this means they are neglecting their duty of care towards uninfected employees. According to some  verdicts , a Covid infection caused by contact with non-isolated colleagues is considered an occupational accident.

This is important: The five-day rule issued during Covid mitigations (mandated isolation time: five days after a positive rapid test) had a political motive, not a medical-empirical one . So as long as a rapid test has two lines, people are infectious and can infect colleagues. According to a US study with the Omicron variant , the infectious period may last for two weeks or more.

The following still applies after the end of official mitigation measures: According to the German Occupational Health and Safety Act, employers are required to regularly - several times a year - update their risk assessment  to the current state of infections. This may include entry bans for infected employees or mandatory high-quality masks (FFP2 or FFP3) in risk-prone settings like hospitals.

2. Respirators

Today, wearing a protective mask against Covid infections is a politically and ideologically charged issue. In some people, the mere sight of them may cause psychological reactance - a resistance to presumed coercive pressure. Trying to justify their rejection, people often refer to a meta-study by research network Cochrane  from the beginning of 2023. It was said to question the protective effect of FFP2 respirators, but this interpretation has since been refuted . The editor-in-chief of Cochrane Library has apologized for statements "that could have been misinterpreted". Many other surveys such as one from Max Planck Institute for Dynamics and Self-Organization  confirm the protective effect of FFP2 respirators.

Many people are not aware that the virus - bound in tiny aerosols - can linger in the air of enclosed spaces for hours, similar to smoke, as a study in the journal "Physics of Fluids"  showed in 2021. "It is, therefore, clear that the six-feet social distancing norm alone is not sufficient to curb disease spread via the airborne route", the authors write. For businesses, this means that all communal areas such as shared offices, kitchens, canteens, elevators or restrooms pose a potential risk of infection, even if no one is present at the moment. This is why high-quality respirators are still the best option to minimize the individual risk of infection. They also shield against cold and flu viruses which have previously shut down many offices during cold season.

3. Communication and role modeling

Even so, a return to mandatory masking in companies seems illusory as the ideological divide regarding Covid protection has become too deep by now. Even hospitals and doctors' surgeries were struggling with resistance from employees and visitors when they reintroduced mask mandates this fall  after a sharp rise in Covid cases.

If leaders in healthcare facilities and other organizations want to reintroduce mask mandates or recommend wearing respirators in situations like face-to-face meetings, they first should counteract widespread disinformation with an information campaign. Social pressure plays a major role in non-masking ("I don't want to be the only one wearing a respirator“). So if leaders were wearing respirators in public at meetings, events and in photos, this could be quite helpful.

Awareness of the risk of repeated Covid infections is still low in the general population. One reason for this is a minimizing language in politics, healthcare and media. "The pandemic is over", German Health Secretary Karl Lauterbach and famous virologist Christian Drosten announced in 2022 and 2023. What the two physicians referred to was the transition to the so-called endemic phase – meaning that the virus is now as indigenous (endemic) in Germany as malaria is in some African countries. What large parts of the population understood, however, was a different message: Covid is over, so we don’t have to protect ourselves any more. Compare that to Africans ripping mosquito nets out of their houses just because malaria is endemic there.

Consequently, leaders should be cautious with their language: Do they refer to "the Covid era" or "after Covid"? This implies that the virus has disappeared and protective measures can be dispensed with. Instead, managers should use neutral phrases such as "during the lockdown" or "after the end of coronavirus mitigations". This sends out a strong signal: Covid has come to stay.

What's more, employees who continue to protect themselves with respirators  are considered overly cautious or peculiar in many companies. Some are even pathologized as over-anxious, even if they have good reasons for their decision. To prevent them from becoming outsiders, managers have a responsibility to back them up: to signal that they respect their personal decision, approve of it and consistently counteract bullying. After all, this means a lower sickness rate in the team.

4. Air filters

Masks are undoubtedly annoying. But there is a tool that has almost the same effect in the fight against Covid infections, but without the ideological load and without restrictions for employees: air filters. These devices filter aerosols from the air by which coronavirus and other pathogens or pollutants spread in enclosed spaces. They significantly improve air quality, making Covid infections much less likely.

The effect of air filters is appreciated in the business world as well. During the World Economic Forum 2023 in Davos, participants were protected by omnipresent air filters, as press photos show . Large mobile filter systems clean the air in German state governments like the Berlin Senate  as well.

Countless surveys  have proven that clean air helps against respiratory diseases and enhances thinking and performance. Although to date few research has been carried out into the effect of air filters against Sars-CoV-2 in offices and other workplaces, the evidence from school surveys is clear: Good ventilation - whether through mobile filters or built-in systems - significantly reduces the number of infections. This can reduce infection rates by 80 percent as a survey from more than 10,000 Italian classrooms  shows.

The only problem with air filters is that they are not cheap to buy and require regular maintenance. Power consumption, however, is relatively low. Devices with class H13 and H14 HEPA filters are most suitable.  They must be able to filter at least six times and up to twelve times the room volume. Example: In a 20 square meter office measuring 4 x 5 x 2.5 meters, the room volume would be 50 cubic meters. Multiplied by six, that's 300 cubic meters, multiplied by twelve, 600 cubic meters. The air filter must be able to handle this volume per hour.

A single filter is not sufficient for larger spaces like conference rooms, however. Here, multiple air filters are necessary. In an experiment in a complexly structured restaurant , physics professor Christian Kähler from Bundeswehr University in Munich has shown how to achieve a sufficient level of clean air. The air filters reduced the concentration of harmful particles in the restaurant by 75 percent compared to a situation without active air purification.

CO₂ levels  are a reliable indicator of indoor air quality. They can be monitored by any commercially available CO₂ measuring device. As a rule of thumb, outdoor air has a level of 400 parts per million (ppm). Indoor levels should ideally be below 800 ppm; if they are higher, ventilation is adivisable. Any figure above 1000 ppm may cause headaches and concentration problems. At such CO₂ levels, the risk of infection by viruses is high.

For companies, the purchase of high-quality air filters for multi-person offices and communal areas can pay off, despite relatively high purchase costs. Over months and years, filters help preventing new infections in the workplace which would result in costly production losses and sick pay.

5. Vaccinations

Employees who want to have their Covid vaccination refreshed should first discuss this with their family doctor, of course. But in recent months it has become increasingly difficult to get a booster shot in Germany. The German Standing Committee on Vaccination (Stiko) has recommended  the vaccination for over 60-year-olds and people with pre-existing conditions only (unlike its US counterpart, the CDC, which considers the vaccination to be advisable for everyone aged six months and over ). Many GP practices in Germany are therefore refusing their patients a Covid booster shot.

This is where employers can step into the breach and offer a vaccination against the latest variants of Covid-19, much like their annual flu vaccination campaigns.