Anticipazione della ricerca dello Sheba Medical Center di Ramat Gan

1. Abstract 03188 – European Congress of Clinical Microbiology & Infectious
Diseases (ECCMID 2022)
Long-term humoral immunity of COVID-19 recovered and BNT162b2
vaccinated individuals: a prospective comparative study
Embargo: 2301H UK time Thursday 10 February, 2022
C. Cohen 1
, Y. Lustig 2, 3
, E. Levin 1, 3
, V. Indenbaum 1
, K. Asraf 1
, C.
Rubin 4
, Y. Kreiss 1
, Gili Regev-Yochay 1, 3
1
Sheba Medical Center - Ramat Gan (Israel), 2
Central Virology Laboratory, Public Health
Authority, Ministry of Health - Ramat Gan (Israel), 3
Sackler School of Medicine - Tel Aviv
(Israel), 4
Gertner institute for epidemiology and health policy research - Ramat Gan
(Israel)
Background
While protection against re-infection lasts for a long time in SARS-CoV-2 recovered patients,
breakthrough infections are significantly induced six months following BNT162b2 vaccination.
We aimed to longitudinally characterize the humoral immune kinetics in COVID-19 recovered
individuals compared to two dose BNT162b2 vaccinated individuals along eight months of
survey.
Methods
We conducted a 12-month follow-up of 130 patients diagnosed with SARS-COV-2 by qRT-
PCR. Data on acute as well as long term (6 weeks) symptoms were collected. We compared
anti-spike IgG and neutralizing antibodies of these patients to an eight months follow-up of
402 age and body mass index (BMI), matched SARS-CoV-2 naïve, vaccinated individuals.
Avidity index for sub-cohorts composed of 16 and 22 recovered and vaccinated individuals,
respectively, was compered at one- and six-month following SARS-CoV-2 diagnosis or
BNT162b2 vaccination. For recovered patients, questionnaires concerning symptoms
including long-covid were collected.
Results
We found higher IgG and neutralizing antibodies at peak titers in the vaccinated cohort than
in the recovered cohort, but also a steeper decline (Fig 1.). Avidity index was higher in
vaccinated individuals than in recovered patients, yet, avidity did not significantly change with
time in vaccinated individuals while avidity gradually increased in recovered patients (Fig 2.).
Interestingly, IgG and Neutralizing Ab of recovered patients with BMI>30 vs. those with BMI
≤30, were higher at all time points (Fig 3.). Of all recovered patients, 42 (36%) individuals
experienced long-covid symptoms including mental (5%), neurologic (9%), cardiovascular
(5%) and respiratory (31%) manifestations.
Conclusions
While the quantity of antibodies decrease with time in both COVID-19 recovered patients and
vaccinated individuals, the quality of antibodies increases following infection but not after
vaccination. Obese individuals have a significantly higher and sustained humoral response
following infection. These results provide specific characteristics of the immune response that
may explain the differential protection against COVID-19 in previously infected and vaccinated
individuals.

2. Figure 1. a. RBD- binding IgG and b. neutralizing antibodies (NAB) distribution and geometric
mean (GMT) along eight and twelve month in BNT162b2 vaccinated and COVID-19 recovered
individuals, respectively. The dashed line indicates the cutoff for diagnostic positivity
Figure 2. Avidity index, indicated as percentage at for recovered individuals compared to
BNT162b2 vaccinated individuals, one and six month after receiving the second dose and,
one, six and 12 month post SARS-COV-2 diagnosis
Figure 3. Antibody distribution, along 12 month of SARS-COV-2 recovered patients with
BMI>30 compared to recovered patients with BMI≤30; a. Distribution and observed
geometric mean of RBD-binding IgG, b. distribution and observed geometric mean of
neutralizing antibodies (NAB). The dashed line indicates the cutoff for diagnostic positivity