The COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2), has captivated the globe's attention since its emergence in 2019. This highly …

Background The future of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-
2) pandemic hinges on virus evolution and duration of immune protection of natural infection …

Three COVID-19 vaccines have received FDA-authorization and are in use in the United
States, but there is limited head-to-head data on the durability of the immune response …

The emergence of Omicron variants coincided with declining vaccine-induced protection
against SARS-CoV-2. Two bivalent mRNA vaccines, mRNA-1273.222 (Moderna) and …

Currently approved vaccines have been successful in preventing the severity of COVID-19
and hospitalization. These vaccines primarily induce humoral immune responses; however …

Background Waning protection against emerging SARS-CoV-2 variants by pre-existing
antibodies elicited because of current vaccination or natural infection is a global concern …

Background In view of limited evidence that specifically addresses vaccine effectiveness
(VE) in the older population, this study aims to evaluate the real-world effectiveness of …

Background: The mass vaccination campaign against SARS-CoV-2 was started in Tunisia
on 13 March 2021 by using progressively seven different vaccines approved for emergency …

Background: The adaptive immune response is a crucial component of the protective
immunity against SARS-CoV-2, generated after infection or vaccination. Methods: We …

Background The immune response to COVID-19-vaccination differs between naïve
vaccinees and those who were previously infected with SARS-CoV-2. Longitudinal …