To find out more about Covid-19, Amsterdam UMC together with the GGD will follow 300 cured corona patients in the coming year. Important questions: how does the immunity develop? Can we explain why one patient becomes deathly ill and the other only experiences mild symptoms? And does the virus permanently damage the lungs?

Such a study is called a longitudinal cohort study, a method of research with which Amsterdam UMC and the GGD have built up a lot of experience. For example, researchers have been following what HIV does to people since the beginning of the AIDS epidemic. Another example is the Helius study, which looks at how the health of the various population groups in Amsterdam has changed over the years.

Tracing 300 patients

For the new corona study, a team led by Professor of Virology Menno de Jong, Professor of Public Health Maria Prins and infectiologist and immunologist Godelieve de Bree is following patients as soon as possible after the infection is diagnosed. "If the patients consent, we start collecting data immediately after their arrival in hospital, or we do it at home if the patient is not too ill. This includes taking blood samples. After recovery, we ask the patient to come to the Covid outpatient clinic or the GGD every month for follow-up testing."

The study was made possible by a grant from ZonMw, which has set aside money for corona research for a year. De Jong: "You don't know how the situation will develop, but the intention is certainly to keep up the cohort study for longer than a year. Covid-19 will be with us for some time yet."

The researchers want to trace 300 people and started this week. They distinguish between two groups. One group consists of patients who have become seriously ill and are in hospital. "We can find these relatively easily because these people are admitted to our hospital," says De Jong. "The second group consists of patients with mild complaints who have proven corona, but are resting at home. We approach this group of people via the GGD."

Biomarkers predict severity Covid

With all the data collected, De Jong hopes to solve a major mystery surrounding Covid-19. Why does one person become deathly ill and a comparable person survive the infection without any significant damage? "Of course gender, underlying diseases and age play a role. That will certainly emerge. We are looking at whether different genes are expressed in the different patient groups and whether different immune cells get to work. It would be nice if we could find biomarkers that predict the severity of the disease or offer points of leverage for new treatments''.

Building immunity

The research question on immunity makes it necessary to follow the patients for a long time. Everyone wants to know whether the antibodies that a patient has built up protect them against a renewed infection and for how long. De Jong: "Insight into how good and long-term immunity to this virus is built up and what factors play a role in this can also be relevant to the development of a vaccine."

Long-term effects

The final research question is looking at lung function. Because the researchers expect most long-term effects in the lungs, they are giving special attention to that. But they are also interested in the effects on general well-being and quality of life.

De Jong hopes that the participants will keep coming for at least a year. Isn't that a long time? "We have experience with other cohorts and know how important a good follow-up of patients is. And we think patients are motivated to participate. Going through Covid-19 is an intense experience at an intense time. This motivates people to participate, also because they know that their health will be closely monitored afterwards. I am very confident that people will continue to participate in this study."