Covid infections between fully vaccinated people reduced by 90%
Share article:
Share article:

Covid infections between fully vaccinated people reduced by 90%

Credit: Belga

Coronavirus vaccines not only reduce the risk of infection, but also make vaccinated people less contagious if they do still get infected, confirms a study by Sciensano, the Belgian health institute, which was published in the international journal Vaccine.

The findings date from the period before the Delta variant became dominant in Belgium.

Between 25 January and 24 June 2021, Belgium made no distinction between (fully) vaccinated and non-vaccinated people after having a high-risk contact.

Whether they were fully vaccinated, partially vaccinated or not vaccinated at all, after a high-risk contact, everyone had to quarantine and have two PCR tests carried out.

Sciensano is now using those test results and contact tracing data to determine how well vaccination protects against infection with the coronavirus.

Vaccinated people less prone to infection after high-risk contact

The researchers compared the risk of a positive test in 8,000 vaccinated high-risk contacts with that in 282,000 unvaccinated high-risk contacts.

The results showed that complete vaccination with an mRNA vaccine (Pfizer or Moderna) reduced the risk of infection by 74% to 85%. Protection was clearly better after complete vaccination than after only 1 dose.

Additionally, the study took into account all positive tests, including those who showed no symptoms, which is why the degree of protection against the coronavirus here is somewhat lower than in studies looking into protection against (severe) symptomatic illness.

Fully vaccinated people with a positive Covid-19 test less likely to transmit virus

The researchers also analysed infections between 990 people who were still infected with the virus after full vaccination (called ‘index cases’) and their unvaccinated high-risk contacts, to study if people who were still infected after being fully vaccinated were just as contagious as unvaccinated infected people.

The vaccinated index cases passed on the virus 52% to 62% less often than unvaccinated index cases, the results showed.

Both types of protection can also occur together, Sciensano stressed.

“If both the index case and its high-risk contact have been fully vaccinated, there are about 90% fewer infections than in contacts between unvaccinated people.”

Alpha vs Delta variant

It is important to keep some precautions in mind, despite these positive results, as this research was carried out during the period when the alpha variant was dominant in Belgium.

“It is possible that protection against the delta variant is less effective,” Sciensano underlined. “However, the researchers have no concrete information on this yet.”

Additionally, the researchers could not make reliable statements on the protection provided by the AstraZeneca and single-dose Johnson & Johnson vaccines, as only a limited number of people had been fully immunised by the end of June.

Sciensano also emphasised that infections between vaccinated people can still occur, and that it is therefore important that everyone follows the current rules.

Latest news

New Belgian video game aims to help children who stutter
A new video game by Belgian-American start-up Say It Labs aims to teach children with a stutter various techniques to improve their speech.  ...
More than 1 in 4 Belgians use mobile phones whilst driving
A recent European study into the use of mobile phones whilst driving highlights some alarming results: 26% of Belgians read or send messages on their ...
Belgium in Brief: Memories Of Masks
Belgium's experts are concerned with the rising coronavirus figures. One possible solution could be that, once again, masks are used more widely. ...
Museum Nights Fever returns to Brussels on Saturday night
After a break last year, Museum Nights Fever 2021 is back again with free visits to 32 museums hosting performances, music and other events. The ...
More than €1.5 billion injected into SNCB
More than €1.5 billion in additional funding has been injected into the Belgian railways, Federal Mobility Minister Georges Gilkinet told the House ...
Non-vaccinated applicants no longer welcome at ZNA hospitals in Antwerp
The Antwerp hospital group ZNA is only taking on new employees who have been vaccinated against the coronavirus, according to reporting from VRT. ...
Pharmacies prepare to administer more rapid antigen tests
From November, anyone presenting coronavirus symptoms for less than six days will be able to take a rapid antigen test in a pharmacy, announced the ...
Chocolate, Christmas, and cocaine
Do you consider yourself a news buff? Someone constantly on top of what's going on? Then maybe you have what it takes to ace The Brussels Times ...
Introduction of Covid Safe Ticket leads more in Brussels to get vaccinated
The introduction of the Covid Safe Ticket (CST) in the Brussels-Capital Region on 15 October seems to have led to a higher number of residents ...
More and more testimonies, and a second rally against sexual violence in Brussels
A second rally against sexual violence was held in the Brussels neighbourhood of Ixelles on Thursday evening, and a sister-rally was held ...
Over 1,000 Covid-19 hospitalisations for first time since early June
The number of patients hospitalised in Belgium as a result of the coronavirus has again exceeded 1,000, climbing to 1,032, according to figures ...
Experts call for more widespread use of masks as figures rise
As coronavirus figures continue to rise, Belgian Prime Minister Alexander De Croo has suggested that people return to wearing masks when indoors with ...