Regular monitoring of SARS-CoV-2 carriage and antibody levels against the virus helped maintain social interactions for Alzheimer's disease residents in a Belgian nursing home during the pandemic

Background People suffering from Alzheimer's disease and related disorders (ADRD) were severely impacted by the COVID-19 pandemic, both physically and mentally. Objective This one-year study aimed to implement a protocol for controlling the spread of SARS-CoV-2 in a Belgian nursing home hosting exclusively patients suffering from ADRD, while minimizing pandemic-associated constraints. Methods After confirming the absence of positive cases in the nursing home and the development of a proper immunity against SARS-CoV-2, the staff members enrolled in the study were allowed to remove their mask. Then, a weekly non-invasive saliva RT-qPCR testing for SARS-CoV-2 detection was implemented to detect cases among the staff and residents. A monthly serological monitoring was set up to follow the levels of neutralizing and IgG antibodies against SARS-CoV-2. Results Three waves of COVID-19 infection were observed and quickly contained thanks to an effective quarantine policy. We confirmed the stronger humoral response developed by people infected before primo-vaccination compared to naïve-vaccinated ones and the weaker immune response of elderly individuals compared to younger participants, a difference abolished by booster. In parallel, we showed that ADRD people were able to develop a similar humoral response to SARS-CoV-2 vaccination or infection to that of people of similar age not suffering from these diseases. Conclusions We show that a strict protocol aimed at early case detection and anti-SARS-CoV-2 immunity follow-up has enabled ADRD residents from a Belgian nursing home to maintain social interactions thanks to the ability of study participants to remove masks, while minimizing the risk of infection.