Only a very small proportion (0.32%) of people in Belgium who have been fully vaccinated and are considered fully immune still test positive for Covid-19, a new study by Sciensano shows.
Since the start of the vaccination campaign, the Sciensano national health institute has been monitoring the occurrence of infections in fully vaccinated people, called “breakthrough infections,” in Belgium by comparing the database of the PCR tests with the database of the vaccinations.
“We note that post-vaccination infections are rare,” said virologist and interfederal Covid-19 spokesperson Steven Van Gucht. “Additionally, we see that in the majority of cases – more than two-thirds of breakthrough infections – no symptoms are seen.”
“This is another convincing indication for the efficacy of the vaccines, also in Belgium.”
On 31 May, more than 2 million people in Belgium (18%) had been vaccinated, and 1.4 million of those could be considered fully immune because they had received their two doses 14 days earlier, according to Van Gucht.
“In that group of 1.4 million fully immune Belgian residents, there were only 4,526 breakthrough infections,” he said, stressing that amounts to a positive test for only 0.32% of the fully vaccinated.
“Therefore, it is clear that people who have been fully vaccinated have a much lower chance of still testing positive for the virus,” Van Gucht said.
“In this case, an infection is defined by having a positive PCR test,” he said. “The clinical picture that accompanies that positive test can be very diverse, ranging from no symptoms at all to mild or severe complaints.”
Additionally, when looking at the last two weeks of May, a total of almost 28,000 new Covid-19 infections were confirmed, of which only 625 (2.35%) occurred in fully vaccinated people.
“However, even more important than the number of positive PCR tests is that no symptoms were observed at the time, or shortly after the positive test was taken for the majority (68%) of these people,” he said.
This means that the majority of these breakthrough infections were not detected because the person felt ill, but because of another reason, such as travel, a high-risk contact or screening in hospital or at an outbreak.
“In hospitals, too, we see that fully vaccinated people are rarely admitted,” Van Gucht said, adding that they represent “just over 1% of all admissions.”
More detailed data on hospital admissions and vaccination status will be published later, as Sciensano will continue to closely examine breakthrough infections and conduct additional studies to identify the risk factors of these infections.
“Among other things, we are looking at the variants, the type of vaccine and the period that has elapsed since the vaccination,” he said. “This will also provide valuable information for the duration of protection of the various covid vaccines.”