Immune Responses to SARS-CoV-2 Infection and Vaccine in a Big Italian COVID-19 Hospital: An 18-Month Follow-Up
Emanuele Sansone,
Carlo Bonfanti,
Emma Sala,
Stefano Renzetti,
Luigina Terlenghi,
Alberto Matteelli,
Mara Maria Tiraboschi,
Tatiana Pedrazzi,
Massimo Lombardo,
Camillo Rossi,
Anna Maria Indelicato,
Arnaldo Caruso,
Giuseppe De Palma
Affiliations
Emanuele Sansone
Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Unit of Occupational Health and Industrial Hygiene, University of Brescia, 25123 Brescia, Italy
Carlo Bonfanti
Department of Molecular and Translational Medicine, Institute of Microbiology, University of Brescia—ASST Spedali Civili, 25123 Brescia, Italy
Emma Sala
Unit of Occupational Health, Hygiene, Toxicology and Prevention, University Hospital ASST Spedali Civili, 25123 Brescia, Italy
Stefano Renzetti
Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Unit of Occupational Health and Industrial Hygiene, University of Brescia, 25123 Brescia, Italy
Luigina Terlenghi
Department of Molecular and Translational Medicine, Institute of Microbiology, University of Brescia—ASST Spedali Civili, 25123 Brescia, Italy
Alberto Matteelli
Department of Infectious and Tropical Diseases, University of Brescia and ASST Spedali Civili, 25123 Brescia, Italy
Mara Maria Tiraboschi
Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Unit of Occupational Health and Industrial Hygiene, University of Brescia, 25123 Brescia, Italy
Tatiana Pedrazzi
Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Unit of Occupational Health and Industrial Hygiene, University of Brescia, 25123 Brescia, Italy
Department of Molecular and Translational Medicine, Institute of Microbiology, University of Brescia—ASST Spedali Civili, 25123 Brescia, Italy
Giuseppe De Palma
Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Unit of Occupational Health and Industrial Hygiene, University of Brescia, 25123 Brescia, Italy
Objectives: This is a longitudinal prospective study which was designed to assess the trend of anti-SARS-CoV-2 antibodies targeting the Spike (anti-S) and Nucleocapside protein (anti-N) viral antigens over a 9-month period after the administration of an anti-SARS-CoV-2 vaccine in a big COVID-19 hospital located in Northern Italy. Participants: 7411 vaccinated workers were included in a linear mixed-effect model analysis performed to model the anti-S decay over the 9 months following the vaccination, during serological screening performed approximately 2, 4, and 9 months following the first jab administration. Serological tests performed in the 9 months preceding vaccine administration were retrospectively analysed to identify the burden of infections occurring before vaccination. Results: The serological assays were used for monitoring the antibody titres during the observational period. Vaccination significantly reduced the rate of infection and elicited a specific humoral response, which lasted during the whole observational period (9 months). A decay was observed in all considered subgroups. At 35 weeks, workers with no history of pre-vaccine infection showed a significantly lower anti-S titre (−2522 U/mL on average (−2589.7 to −2445.7)); younger workers showed significantly higher anti-S titres (140.2 U/mL on average (82.4 to 201.3)). Only seven immunocompromised workers did not show significant levels of anti-S antibodies; three of them, all females, showed a specific T-cell response. Conclusions: Comparing the 9-month periods before and after the first vaccine dose, a significant reduction in infection rate was observed (1708 cases vs. 156). Pre-vaccine infection, especially if contracted during the first pandemic wave, greatly enhanced the response to vaccination, which was significantly affected also by age both in extent and duration (inversely related). A gender effect on the T-cell immune response was observed in a small group of workers who did not produce antibodies after vaccine administration.
