Tom Kobel

Tom Kobel

The topic of COVID vaccinations is still being discussed in great detail – not just protection against infection, but also the possible therapeutic effects in cases of Long COVID. Half a year has passed since our last interview on the topic, which means that it’s high time for an update. What has happened in research since then?

Jan Fehr, COVID vaccinations could also have therapeutic effects for those affected by Long COVID. Do we now know if this is the case, and if the answer is yes, who the vaccination can help?

There’s a new study from France, in which almost 1,000 affected people were examined: 455 received the vaccination, and a control group of 455 people did not receive the vaccination. Four months later, symptoms in those vaccinated were, on average, reduced compared to the unvaccinated. In fact, the rate of those who had recovered completely was double that among the vaccinated than the unvaccinated. So there may be something there that signals that the vaccination could have a therapeutic effect.


"Based on data available to date, the vaccination is generally considered safe even for those affected by Long COVID."

The vaccination didn’t help everyone, however. Around 5% experienced unwanted side effects, and around 3% reported a relapse. Do we already know who can benefit from a vaccination, and who cannot?

No, we currently can’t say. It is, of course, something that we would be very interested in knowing. The studies available are, however, still too vague, and too small to find out who would benefit most from the vaccination. The French study also hasn’t been peer-reviewed yet. But based on data available to date, the vaccination is generally considered to be safe even for those affected by Long COVID.

How sustainable are the improvements from the vaccination? Do the improvements last for a long time?

We also can’t comment on this with any certainty. The vaccination certainly isn’t a cure-all. Other research groups are working on this question, but it takes time. Good data requires great care, and it doesn’t happen overnight. I know it can be frustrating. But I want to ask for understanding on this. Good, reliable science takes a lot of effort.


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Jan Fehr (48) is a professor for health and travel at the University of Zurich. He is a specialist in Infectious diseases and Internal Medicine, and heads the Public & Global Health department. The Canton of Zurich’s Vaccination Reference Center is also part of his department.

Has the Yale University study, led by Professor Iwasaki, produced any more findings in the meantime?

This study is also still ongoing. We’re expecting the first results from the pilot phase at the turn of the year. A larger study is planned to start at the beginning of 2022. This shows that even the most renowned universities in the world can’t just pull something out of a hat. It requires patience – more than even I realized during the spring.

Now for the practical questions: how long should you wait after infection before getting vaccinated?

The new recommendation is that you should now wait three months after infection before getting vaccinated – with one dose. Those who think a second dose could be helpful should discuss this with their doctor. It’s not out of the question.

What role does the vaccine play?

In the study from France, most received the Pfizer vaccine. Only a small percentage received Moderna. However, the different vaccines have not been explicitly researched and compared with regard to their effect on Long COVID.

Should those affected get the booster shot?

Yes. Basically, you should get the booster shot, especially in view of possible reinfections with Omicron. However, what applies in general, may not be appropriate for an individual case. If in doubt, you should discuss the decision with a specialist.

Jan Fehr

How should we assess reports from those who were set back by the vaccination?

I can’t rule out that it happens. In any case, the reports should be taken seriously. After all, something happens in the immune system – and that’s exactly what we are aiming for with the vaccination! It’s just like a mixing console – you have to find the right balance. We do not currently know exactly which control settings are right for which people. According to the French study, relapses are proportionally less frequent.

In view of the unclear study situation: what is your advice if someone is unsure if they should get vaccinated or not?

In this case, I advocate for "shared decision making" – this means that the decision is made together with and on equal footing with their doctor. There is no guarantee of a positive effect or that risks are 100% eliminated, and every person has their own story. It is entirely individual. It’s about being able to make a well-informed decision and during this process, developing realistic expectations of which effects may or may not occur. It is always a balancing act between possible gains and risks.

If you don’t get vaccinated, you run a higher risk of getting infected again.

Yes, we know that immunity to reinfection decreases over time. However, reinfection could also set back someone who is in the recovery phase. But we don’t know whether reinfection is worse for those suffering from Long COVID than for those who have recovered.

Those who haven’t had COVID-19 and are vaccinated: does the vaccination protect against Long COVID in the case of a breakthrough infection?

The vaccination does not provide 100% protection. However, firstly, the risk of becoming infected after you’ve been vaccinated is markedly lower. And secondly, if still you end up getting infected, the risk of suffering from Long COVID is about half as high as it is for someone who is unvaccinated and gets infected. This has been shown in a study from England.

However, it has also been suggested in various cases that vaccination can even trigger Long COVID. What is your opinion on this?

To this day, eight billion vaccinations have been administered and I have not heard of a phenomenon comparable to Long COVID that has such a high prevalence. It is also hard for me to imagine, when I think of the pathogenesis, what could trigger an illness.

What do you mean?

The mRNA vaccination is very precise. It’s like a surgical procedure that deceives the body so it can produce the required antibodies. But it doesn’t cause the full illness, no systemic disease in which all the organs and vessels can be involved. This is exactly what we want to prevent from happening with the vaccination.

Can you rule it out?

I don’t want to say that it isn’t possible. It is, in any case, important to take these patients seriously, to listen to them and examine them carefully. They have something, and even if, strictly speaking, it might not be Long COVID, we cannot know for certain using current methods.