Do you react more strongly to the vaccine if you have already had corona (unnoticed)?
Headache, feeling unwell, muscle pain, fatigue, chills, fever, joint pain and nausea: these are the side effects of the different corona vaccines the most commonly reported to date at the Lareb side effect center. In some people it seems as if they all present themselves at the same time and last for days.
They are regularly told that they may have been infected with the corona virus without knowing it. Because their side effects are reminiscent of the strong reaction the vaccine can induce in people who, because they tested positive before, are known to have been infected.
Research published last month indeed seems to indicate side effects among previously infected persons occur significantly more often than among people who had not had the coronavirus: 89 to 46 percent. The side effects were also more severe in the first group. Fatigue was most commonly reported, followed by headache, chills, muscle aches, fever and joint pain.
No hospital admissions
Two important caveats: The study participants had received vaccines from Pfizer or Moderna, both of which are made using the relatively new mRNA technique. Side effects may be different in people vaccinated with the AstraZeneca vaccine (Janssen’s vaccine was not in use at the time of the study). Point two: no one had side effects that were so severe that he or she had to be hospitalized. So it was at most a matter of getting away from home.
Ben van der Zeijst, emeritus professor of vaccine development, says: “It is known that people who have already been infected can react quite vigorously to the first vaccination and that they are more likely to experience side effects.” He attributes it to a “very high antibody response,” which is much more potent than in other people.
It could be that these side effects, in people who have already been infected, turn out even more powerful after the second vaccination. “There is some concern about that,” says Van der Zeijst. “It is not without reason that the Health Council recommends that people who have already had the coronavirus should only be vaccinated once.”
Super well protected
The antibody response is ten to thirty times higher in people who are known to have been infected. After one shot they are ‘super well protected’, says Van der Zeijst. The point is of course: the Health Council’s advice to limit it to one dose applies to people who do tested positive less than six months ago. But what if you haven’t been tested at all and have had the virus without knowing it?
That remains a problem, says Van der Zeijst. “Ideally, you might screen people for antibodies before they get a shot. But that’s practically impossible now that millions of people are being vaccinated in such a short amount of time.”