Anyone who is vaccinated is protected from the coronavirus. There are tests to find out how many antibodies a person has. However, a resident living near the Moselle river was quite surprised to find out that when he was tested for antibodies, it turned out that he did not have enough, despite the vaccination. Our RTL.lu colleague Pit Everling asked what this means.
Jacques Zeyen was vaccinated on 15 April and received the Johnson&Johnson vaccine, which requires only one dose. He recently had a test done to measure his level of antibodies and was surprised to learn that he did not have that many. A level of 11 or above is considered valid, while anything below 8 is seen as not enough. Zeyen had 8.01. After receiving the results, he explained, he “obviously” wondered whether his protection is enough.
To answer this question, RTL got in touch with Dr Claude Muller, a virologist. He explains that antibodies are not the only thing that counts. The human immune response is composed of two parts.
The antibodies are the first part, but there is also the cellular immune response. What needs to be considered is that the antibody test just measures the antibodies and not the cellular immune response. But both elements contribute to vaccine protection, Dr Muller explains.
It is thus possible for a person to still be protected by cellular immunity, which is, however, difficult to measure. Studies suggest that a certain percentage of people have a relatively weak response to vaccination. This could be the case in the elderly or those suffering from certain diseases. If someone is in a grey area in terms of antibodies, Dr Muller recommends another test first, e.g. waiting one month and taking a blood test – not a dry blood spot, however, as Dr Muller points out that this type of test is “less sensitive”.
Professor Muller is in fact not opposed to an additional vaccination dose in certain cases.
In the case of Jacques Zeyen, however, the National Health Directorate ended up taking a different stance, stating that no link could be made between the number of antibodies and the level of protection. According to Zeyen, he was told that he does not have to worry and that his vaccination is “sufficient”. He is thus not eligible for a booster shot or a second vaccine.
This means that Zeyen is considered “fully vaccinated”, as additional doses are currently only being considered for immunodeficient patients. Upon enquiry by RTL, the National Health Directorate said it would decide on a case-by-case basis in these situations.
The full report in Luxembourgish:
