Since the start of the vaccination campaign Sciensano has been following so-called “breakthrough infections”, coronavirus infections among those that have already been immunised against the virus. The public health science institute found that no more that 3 out of every 1,000 people that had already been fully immunised became infected with coronavirus. Moreover, of these 2 out 3 showed no symptoms. This shows that the vaccines are proving highly effective in protecting us against the virus.
By linking the COVID-19 Vaccination Register to the database containing the coronavirus test results. Sciensano was able to find 4,526 cases of people that had been fully immunised, but tested positive for coronavirus. This is just 0.32% of the people that are considered to be fully immunised or just over 3 in every 1,000.
During the last week of May there were just 652 “breakthrough” infections out of a total of 27,979 positive coronavirus tests. This means that infections among those that had been fully immunised accounted for just 2.33% of the total number of positive coronavirus tests. As by then around 20% of the total population had been fully immunised this seems to prove that vaccination greatly reduces a person’s susceptibility to infection.
Hardly any symptoms
Sciencesano was able to gather further information about 74% of all “breakthrough infections”.
68.1% of fully immunised people that nevertheless became infected with COVID-19 showed no symptoms. The majority of the infections that were discovered were discovered by chance through testing that was carried out for other reasons than illness (travel, following a high-risk contact, screening…).
Sciensano says that it intends to continue to study infections among the immunised. The public health science institute will look into the risk factor and see if such infections are more prevalent among certain groups or if there are differences depending on which vaccine has been administered. Sciensano will also examine whether certain variants of the virus are more prevalent among than others among the “breakthrough infections”.
Among those that develop symptoms, Sciensano will examine how the seriousness of the illness caused be the infection differs between them and those that haven’t been immunised.