According to research conducted by the Dutch blood bank Sanquin, an average of 13,3 percent of people in the Netherlands has already produced antibodies against COVID-19.
Every week, Sanquin’s “Finger on the Pulse” (Vinger aan de Pols, VAP) study examines the blood of around 2.000 blood donors for traces of antibodies. In the first week of January, traces of the virus were found in 13,3 percent of blood donors - a 3 percent increase since the beginning of December. 13,3 percent amounts to approximately 2,3 million people nationally.
In the South East of the Netherlands (Limburg and North Brabant), antibodies were found in the blood of around 15,5 percent of donors. Amsterdam, Utrecht, and Haarlem have the lowest national figure with “only” around 11,5 percent. In Rotterdam and The Hague the figure is slightly higher at 12,5 percent. According Sanquin, the antibodies are key to providing long-term protection against the virus.
Since last spring, Sanquin has been researching the blood of around 600 people, all of whom had become infected with COVID-19. Their studies found that, even after eight months, coronavirus antibodies could still be detected in the blood of almost everyone involved in the study. The antibody that provides longer protection against the virus, IgG, was also found.
The research confirms the results of other studies conducted around the world: former COVID-19 patients remain immune to the virus for at least six to eight months after first becoming infected. However, according to Marjolein van Egmond, an immunologist at Amsterdam UMC, it remains unclear how many antibodies are required in order to be fully immune and to avoid further spread of the virus.