What about immunity?

A study by the prestigious King’s College in London shows that antibody-based immunity to the coronavirus usually disappears after a few months.


In the event of an infection, such as the coronavirus, white blood cells of the innate immune system come into action first. If they fail to eliminate the virus, other white blood cells, called B cells, come into play.
In the process, they produce neutralizing antibodies, which attack the virus in a targeted manner to eliminate it. After the virus is eliminated, sometimes some of those antibodies remain in the blood. The virus can be eliminated much more quickly the next time it is infected – this is called immunity. In the case of the coronavirus, it now seems that the antibodies disappear over time. So they may not provide lasting protection.
However, antibodies are not the only part of the highly complex immune system. The rapid disappearance of antibodies from the body does not necessarily mean that a person will be susceptible to a second infection with the coronavirus again. In addition to antibodies, there are also the so-called killer T-cells. These are immune cells that can destroy the virus in infected body cells. Besides, there are also the “memory B-cells”, which can produce new antibodies much more quickly on new contact with the virus.


Researchers from the Shanghai Public Health Clinical Center, among others, studied 175 recovered, mild Chinese covid-19 patients. This involved measuring the amount of neutralizing antibodies in the blood plasma several weeks after they had recovered from the infection. In a third of the participants, the level of these antibodies was quite low. In ten patients, the amount of antibody was not even detectable. Briefly, in the first weeks, the researchers found high antibody levels in 60% of the cases. After three months, these could only be found in 17% of the cases.

The research group of Marion Koopmans, professor of virology at the Erasmus Medical Center in Rotterdam, is also investigating how much antibody people build up after a mild covid-19 infection and, like the Chinese, they find varying levels.

The King’s College study confirms earlier suspicions about the disappearance of antibodies to the coronavirus. The researchers regularly checked the blood for antibodies of about 70 people who tested positive for the virus. They did this until 94 days after the onset of symptoms.

After the onset of symptoms, the number of antibodies in the blood increased. During the following three months, they gradually decreased again. Persons with a more severe infection had higher values of antibodies in the blood than persons with milder symptoms.


Current blood tests that detect the antibodies teach us whether a person has recently been in contact with the coronavirus. Because the antibodies disappear, they do not provide lasting immunity. Therefore, individuals who experienced COVID-19 must still adhere to all preventive measures.
Scientists have not yet figured out which and how many antibodies, T-cells, or B-cells are needed to have sufficient immunity. The new virus is still too unknown for this. However, there is plenty of research going on.


The British research confirms the suspicion that antibodies against the coronavirus gradually disappear from the blood. However, our immune system consists of more than just antibodies. To build up immunity, the immune system must be stimulated sufficiently and this does not seem to be the case for everyone who gets infected.
At the moment we do not know whether someone who has gone through COVID-19 will have long-term immunity to a new infection with the virus. Therefore, everyone should continue to follow preventive measures.

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