Characterization of anti-SARS-CoV-2 humoral immunity among health care workers in hospitals from the islands of Santiago and São Vicente, Cabo Verde

Inês Rodrigues, Kleidi Santos, Tamar Monteiro, Mérita Fidalgo, Jacqueline Monteiro, Ofélia Monteiro, Janaína Vicente, José Luís Spencer, Isaquel Silva, Elsi Ca, Lídia Nhamussua, Sebastian Nielsen, Pedro Aide, P Ferrinho, Frederik Schaltz-Buchholzer, Maria da Luz Lima Mendonça, António Pedro Delgado, Christine Stabell Benn, I Fronteira, Isabel de Pina Araújo

Research output: Contribution to conferenceAbstractpeer-review



Health Care Workers (HCW) faced a high risk of
exposure to SARS-CoV-2.
In the present study, we described the presence and duration of
anti-S and anti-N IgG antibodies against SARS-CoV-2 among
HCW to evaluate the immunity response induced by either
SARS-CoV-2 infection or COVID-19 vaccination.
Methods Case-cohort study of 465 HCW from hospitals from
the islands of Santiago and São Vicente, conducted in 2021, of
which 217 were cases (SARS-CoV-2 infection) and 248 controls
(no SARS-CoV-2 infection). Study participants were followed-up
until 6 months after recruitment for longitudinal analysis of
antibody dynamics, independently of SARS-CoV-2 vaccination
status. ELISA test for anti-N and anti-S1 SARS-CoV-2 IgG
antibodies were performed on serum samples using collected at
baseline (T0) and at 6 months (T6). Among vaccinated
participants, these two time points corresponded to a mean time
from vaccination of 115 (SD: 60 days) and 350 days (SD: 74 days)
Results Of the 396/465 (85%) tested for anti-SARS-CoV-2
antibodies at T0, 36% (n=66/185) of cases and 12% of controls
(n=26/211) were positive for anti-N.
Among the vaccinated at T0 165/166 (96%) cases and 200/205
(97%) controls were positive for anti-S1.
The anti-S1 among the case and control group remained high at
T6, with 177/179 (99%) cases and 197/198 (99%) controls of
HCW tested at 6 months being positive.
Among 250 (67%) vaccinated, who were anti-N negative at T0-
,115(32%) remain negative at T6.
Conclusion These findings showed that only 31% of cases had
anti-N. The results also showed positive results for IgG anti-N in
HCW without previous SARS-CoV-2 infection, which could be
considered asymptomatic cases. Most vaccinated participants
had Anti-S after vaccination and they remained high during the 6
months of follow-up. Nonetheless, at least (65/354) had a new
infection (32 cases, 33 controls).
Funding: EDCTP (RIA2020EF-3049)
Original languageEnglish
Publication statusPublished - 2023
EventEDCTP Forum: Partnering for Global Health Research Innovation and Impact in Africa - Paris, France, Paris, France
Duration: 7 Nov 202310 Nov 2023
Conference number: 11


ConferenceEDCTP Forum
Abbreviated titleEDCTP Forum


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