There are very few long-term studies that analyze the immune responses in patientsrecovered from COVID-19 caused by the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).The main aim of this study is to analyze the clinical profile and immune responses ofrecovered COVID-19 patients in a representative cohort of people in the Umbria region ofItaly. The participants had a history of testing positive for SARS-CoV-2 in March 2020 byReverse Transcriptase- Quantitative Polymerase Chain Reaction (RT-qPCR). The participantswere invited for voluntary participation in a seroprevalence study. This study analyzeslongitudinally the presence of antibodies against SARS-CoV-2 by sequential serologicaltests at different time points using two FDA-approved Immunoassays. At the first serumsample collection, the participants were asked to provide information about theirCOVID-19 clinical history including clinical profile, co-morbidities, and treatmentundertaken using a standardized questionnaire. Successive sequential serologicalassessments were conducted to understand the immune responses in these recoveredpatients.Moreover, stage two of the study involves, analysis of antibody titers in recoveredvaccinated individuals and their follow-up.
Study design: A monocentric pilot longitudinal observational study
Study subjects: patients recovered from SARS-CoV-2 infection in March 2020 (detected by
RT-PCR)
Study method: The study was conducted after written informed consent for voluntary
participation. The antibody titers were longitudinally analyzed by sequential serological
tests at different time points (TPs) using two FDA-approved Immunoassays. At the first
serum sample collection, the participants were asked to provide information about their
COVID-19 clinical history including clinical profile, co-morbidities, and the treatment
undertaken using a standardized questionnaire.
From May 2020 to January 2021:
Anti-Nucleocapsid (NCP) antibodies were analyzed using FDA-approved CLIA immunoassay
through sequential serum samples.
Time was treated as a factor and six different time points (TPs) were defined (T0-T5).
The first blood sample was collected in the month of May 2020, 2 months after the month
of infection (March), and was defined as T0. Consecutive serological samples were
analyzed at different TPs; three months (T1), five months (T2), seven months (T3), eight
months (T4), and ten months (T5) post-infection in June, August, October, November of
2020 and January 2021 respectively.
At this point, a more specific immunoassay was adopted to detect neutralizing antibodies
against the Spike-Receptor binding domain for future assessments.
From late February 2021:
an additional n=12 patients (8 female and 4 male), who met the eligibility criteria for
participation, were enrolled in the study and added to the original cohort (n=30). These
patients (n=12), similar to the original cohort, had a history of testing positive for
SARS-CoV-2 by RT-qPCR in March 2020, updating the sample size to n=42.
Since the legal provisions adopted by the Italian Ministry of Health advised mandatory
vaccination for all Healthcare Workers, irrespective of previous disease status, n=10
patients (4 female and 6 male) were gradually vaccinated from mid-March 2021 and hence
excluded from the original cohort, making the revised final sample size as n=32.
The presence of antibodies was analyzed The study continues to actively enroll patients
for future analysis.
with vaccination in progress, the antibody titers of the recovered and then vaccinated
patients will also be analysed separately.
Diagnostic Test: COVID-19 antibody test
FDA-approved Immunoassays were used in the study. At the beginning of the study, up to 3
months, ELISA and CLIA immunoassays were adopted to analyze the antibody titers.
Thereafter, CLIA was used for longitudinal analysis of antibody titers for consecutive
months. Anti
Inclusion Criteria:
1. Individuals who tested positive for SARS-CoV-2 in March 2020. These patients will be
divided into two groups and followed up over time. The first group will include
patients who have recovered and have not received the vaccine. The second group will
include patients who have recovered and have received the vaccine.
2. No acute respiratory infection or active SARS-CoV-2 infection.
3. Informed consent of the adult participant.
Exclusion Criteria:
1. Individuals <18 years or >80 years.
2. No informed consent by the adult participant.
3. Suspicion of acute COVID-19 infection
Associazione Naso Sano
San Mariano, Perugia, Italy
Puya Dehgani-Mobaraki, MD, Principal Investigator
Associazione Naso sano, Italy