Skip to ContentSkip to Navigation
About us Latest news News Worldwide Newsletter

Predicting the future of COVID-19 is like reading coffee grounds

It won't exterminate us, but it is impossible to predict how a pandemic of a new virus such as COVID-19 will develop, according to microbiologist Marjolein Knoester. It might even lie low, to return next year.

Marjolein Knoester
Marjolein Knoester


You could consider this article to be a time capsule. At the end of February, we interviewed Marjolein Knoester, director of the Medical Microbiology and Infection Prevention clinic at the UMCG, about the new coronavirus COVID-19. Two days after the interview, the virus reached the Netherlands on the heels of infections across Northern Italy and Germany, among other places. Much is still unclear. Will the whole world be exterminated or will it all blow over? Now, at the start of April, as this edition of Broerstraat 5 is being delivered through your letter box, we may know the answer.

'Well, we won't be exterminated', laughs Knoester. 'We have already seen in China that most of the people who caught the virus did not die. A far higher percentage of the people who caught the virus from animals at the market in Wuhan died than those who were infected later. It appears that the virus changed, so that it has become transmittable from person to person but is also less deadly.'


Compare these observations to other coronaviruses, such as MERS and SARS, and the differences are striking. 30 percent of MERS patients died, as did 10 percent of SARS patients, which has since been eradicated. The COVID-19 death rate is stuck at 2 percent. The current coronavirus appears to be the opposite of MERS, which was transmitted from camels to humans and was less easily transmittable from person to person - one of the reasons why it didn't spread much further than the Middle East. The infection risk of COVID-19 is around the same as that of the flu, with one person usually infecting two other people.

How can these differences be explained? 'You can't always assign one reason for this', says Knoester. 'A virus is a strain of RNA (ribonucleic acid) or DNA, with a protein capsule around it. How infectious a virus is depends on, for example, whether the capsule itself is contained in an envelope, a shell of greasy substances.'

Chicken pox

'Influenza has an envelope. This virus is easily transmittable but, because the envelope dries out outside the body, it can't survive on surfaces for long. The norovirus - the 'stomach flu virus' - can live on surfaces because it doesn't have an envelope. If someone with the norovirus doesn't wash their hands well, they can very easily infect the toilet door handle. Part of the reason why chicken pox is so infectious is because it is spread before the person even starts to notice symptoms. With a new virus, you need to just wait and see how it is carried.'

Knoester doesn't want to judge or dismiss the face masks that have appeared in locations with many COVID-19 infections as useless, but she emphasizes that they must be thought about rationally. 'If you cough in my face and I am wearing a face mask, then this is safer than not wearing a mask. That's the idea behind the flimsy face masks that people in risk areas are wearing. But if you stand one and a half metres away from someone, then that is also safe.'

Face mask

Knoester makes a comparison with her own workplace, the UMCG. 'If patients come to us with the flu, they have to wear a face mask in the waiting room so that they can't infect anyone. FFP2 masks - the thick, white face masks - are in principle reserved for doctors and nurses. No virus can penetrate these masks, so the healthcare staff cannot get ill themselves or transfer the virus to the next patient. It is very important that patients here are safe and do not take any virus or bacteria back home with them. With my department, I am contributing to a hospital-wide initiative to make protocols to prevent such infections.'

Transplant patients

What does Knoester do at work, in a nutshell? Since mid-January, as the director of the Medical Microbiology and Infection Prevention clinic at the UMCG, she has been responsible for the translation of lab reports and diagnostics for the doctors who are treating patients. She doesn't provide any patient care herself. 'Patient care in virology at the UMCG mainly involves transplant patients. All transplants imaginable are done here: lung, heart, small intestine, kidney, liver, stem cell. These patients all run the risk of contracting and reactivating virus infections.

If you've ever had glandular fever, for example, you will (generally) never have it again. But in someone who has had a heart transplant, this virus can be reactivated and could even cause cancer. So in these cases, we monitor the virus after transplantation. There are so many viral infections, from minor ones like cold sores to major ones like glandular fever.'

Clinical leadership programme

Knoester finds it valuable that the UMCG does not expect its scientists to only have research as their main goal. 'The UMCG emphasizes that healthcare and teaching are also very important', says Knoester. 'The hospital is now busy developing a clinical leadership programme. That's new as previously, if you worked at an academic level, you only counted if you continued doing research and then became a professor. Now, people are also finding it important to invest in the organization of healthcare and teaching. Because all new doctors do need to be trained.'

Patient safety

Knoester doesn't consider it bad that this programme doesn't lead to professorship. 'What I find important is that I no longer have to spend my time applying for grants but that I can commit myself to improving healthcare processes and as a result, patient care. As a recently appointed clinic director, I am now at a point in my career where I need to learn what you need to inspire and give leadership to people. And therefore, to achieve what is necessary for the patients.'


Fast forward to 23 March, just before Broerstraat 5 goes to the printer. Everyone in the Netherlands is sitting at home and hospitals are making every effort to prepare for a large wave of infections. Scientists are recording their first successes with medicines, quick testing and vaccines. The pandemic could well last until after the summer. Or, as Knoester already said at the end of February: 'The question is whether the coronavirus, just like SARS, will disappear or whether, just like the flu, it will lie low somewhere for the rest of the year, to return next winter. The chances are quite high that we will be saying 'here it comes again' next year, but hopefully we will then be a bit more relaxed as we will know that the virus will not get worse.'


Marjolein Knoester (1979) studied medicine at Leiden University, where she also obtained her PhD. From 2009 to 2015, she was in training to become a microbiology specialist at the department of Medical Microbiology at the Leiden University Medical Center. Since 2015, she has worked as a microbiology specialist, focusing on virology, at the UMCG. Last January, she became director of the Medical Microbiology and Infection Prevention clinic at the UMCG.

Source: Broerstraat 5, april 2020

Last modified:10 April 2020 08.47 a.m.
View this page in: Nederlands