Coronavirus transmissionBelgian study says vaccination decreases infection risk

The Sciensano Scientific Institute of Public Health has conducted a study of 300,000 contact cases studied in Belgium between January and June 2021.

The conclusion of the research seems positive:

• When compared with two unvaccinated people, the risk of transmission drops to 62% when the infected person is vaccinated.
• The decrease is 85% when the high risk contact is vaccinated.
• And when both people are vaccinated, researchers observed 90% less risk of infection.

Jean-Michel Dogné, expert at the Federal Agency for Medicines and Health Products, said that being vaccinated with two doses clearly reduces the risk of infection. More importantly, the risk is particularly low when the person transmitting the virus and the close contact are both vaccinated.

The study supports the use of the CovidSafe (or CovidCheck) certificates, due to the decrease in infections among vaccinated people.

However, one of the limitations of the study is that it was carried out between January and June. The more virulent Delta variant was not yet predominant among infections, or at least not to the extent that it is today. Despite this, recent data is somewhat reassuring on the topic, said Dogné, as infections are still mostly present in unvaccinated people, particularly in early August when the Delta variant was predominant.

Finally, it is worth noting that these conclusions relate to mRNA vaccines such as Pfizer/Biontech and Moderna. Researchers did not have sufficient data for the J&J and AstraZeneca vaccines.