SARS-CoV-2 Infection in COVID-19 Vaccinated Patients

Vaccination of the population is crucial in the fight against the COVID-19 pandemic. Although most available vaccines have an estimated efficacy against symptomatic infection of 65-95%, this can be significantly reduced if the patient has co-morbidities such as immunosuppression or if the full vaccination schedule is not followed. Infection with SARS-CoV-2 variants, carrying mutations, notably on the spike protein, may also be associated with escape from immunity acquired by vaccination. Indeed, in vitro studies have shown a decrease in sensitivity to neutralizing antibodies acquired after vaccination or even after infection for certain variants such as variant B.1.351 (beta variant according to the WHO, first detection in South Africa) or variant B.1.617.2. (delta variant according to the WHO, first detection in India). On the other hand, cases of COVID-19 following a full vaccination regimen have recently been reported. With the increasing detection of new variants and in the context of increasing vaccination coverage of the population, one of the priority missions of the National Reference Centre (NRC) for respiratory infection viruses is to clinically and virologically investigate all cases of infection in vaccinated patients. The main objective is to determine whether a particular variant is over-represented in vaccinated patients with an infection. The secondary objective is to study the humoral immune response in COVID-19 vaccinated patients with and without SARS-CoV-2 infection.