Abstract
Europe is experiencing a third wave of COVID-19 due to the spread of highly transmissible SARS-CoV-2 variants. A number of positive and negative factors constantly shape the rates of COVID-19 infections, hospitalization, and mortality. Among these factors, the rise in increasingly transmissible variants on one side and the effect of vaccinations on the other side create a picture deeply different from that of the first pandemic wave. Starting from the observation that in several European countries the number of COVID-19 infections in the second and third pandemic wave increased without a proportional rise in disease severity and mortality, we hypothesize the existence of an additional factor influencing SARS-CoV-2 dynamics. This factor consists of an immune defence against severe COVID-19, provided by SARS-CoV-2-specific T cells progressively developing upon natural exposure to low virus doses present in populated environments. As suggested by recent studies, low-dose viral particles entering the respiratory and intestinal tracts may be able to induce T cell memory in the absence of inflammation, potentially resulting in different degrees of immunization. In this scenario, non-pharmaceutical interventions would play a double role, one in the short term by reducing the detrimental spreading of SARS-CoV-2 particles, and one in the long term by allowing the development of a widespread (although heterogeneous and uncontrollable) form of immune protection.
Lingua originale | Inglese |
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pagine (da-a) | 961-N/A |
Rivista | Viruses |
Volume | 13 |
Numero di pubblicazione | 6 |
DOI | |
Stato di pubblicazione | Pubblicato - 2021 |
All Science Journal Classification (ASJC) codes
- Malattie Infettive
- Virologia
Keywords
- COVID-19
- Dose-Response Relationship
- Environmental Exposure
- Environmental exposure
- Facial masking
- Fomites
- Humans
- Immunologic
- Immunologic Memory
- Memory T cells
- Protective immunity
- SARS-CoV-2
- T cell responses
- T-Lymphocytes