Circulating anti-SARS-CoV-2 nucleocapsid (N)-protein antibodies and anti-SARS-CoV-2 spike (S)-protein antibodies in an African setting: herd immunity, not there yet!

Abstract

Objective Herd immunity is achieved when in a population, immune individuals are in a sufficiently large proportion. Neutralizing antibodies specific to SARS-CoV-2 that are produced following infection or vaccination are critical for controlling the spread of COVID-19. The objective of the present work was to investigate the rate of SARS-CoV-2 natural immunization in Gabonese. Results One thousand, four hundred and ninety two people were enrolled. The overall prevalence of anti-SARS-CoV-2 antibodies was 36.2%. Moreover, 76.4% of people who developed a humoral response to SARS-CoV-2 produced both anti-SARS-CoV-2 N-protein antibodies and anti-SARS-CoV-2 S-protein antibodies, which correspond to 27.7% of the total population. In infants (0–9 month), children (1–17 years) and adults, the prevalence of anti-SARS-CoV-2 antibodies was relatively the same, between 33 and 37% (any antibody types) and between 25 and 28.6% (neutralizing antibodies). In this African context, one-third (1/3) of the screened population was exposed to SARS-CoV-2 and three-quarter (3/4) of those exposed individuals developed neutralizing antibodies against SARS-CoV-2. This data suggest that herd immunity is not yet to be achieved in Gabon.

SARS-CoV-2 Antibody Seroprevalence in Gabon: Findings from the Nationwide Household Serosurvey in a Sub-Saharan Africa Country

“…A ten folds increase was observed in rural areas during the same period. This corroborates the observation in South Africa where the authors collected blood from urban and rural cohorts every two months from July 2020 to March 2021 [9]. During this ninemonth study, the seroprevalence increased from 1% to 26% in rural settings and from 15% to 41% in urban communities after the two waves of COVID-19.…”

Time to SARS‐CoV‐2 clearance in African, Caucasian, and Asian ethnic groups

“…S1 covered April to September 2021, and S2 went from October 2021 to March 2022. The Gabon population immunization rate (natural and/or vaccinated) was estimated between 13% and 36% for the S1 11 , 12 and 87% for the S2. 6 …”

“…S1 covered April to September 2021, and S2 went from October 2021 to March 2022. The Gabon population immunization rate (natural and/or vaccinated) was estimated between 13% and 36% for the S1 11,12 and 87% for the S2. 6 Participants were recruited in the setting of Aries Medicus Clinic and its associated containment sites.…”

“…A recent study showed pre-existing crossreactive humoral immunity to SARS-CoV-2 in the Gabonese population, 9 Tanzanian, and Zambian. 10 SARS-CoV-2 immunity produced following infection or vaccination is critical for controlling the spread of In Gabon between April to September 2021 (Semester 1 [S1]), up to 36% of the population showed signs of immunization, 11,12 and between October 2021 to March 2022 (Semester 2 [S2]), 87% of the populations tested positive for anti-SARS-CoV-2 antibodies. 6 The first the part of S1 was characterized by the circulation of the alpha (α) variant (B.1.1.7 [40%]), the eta (η) variant (B.…”

Complement contributions to COVID-19

“…Further driving the lectin pathway, a conserved motif within the virus-encoded nucleocapsid (N) protein binds to MASP-2, triggering its dimerization and autoactivation, thus, increasing C4 cleavage, and accelerating formation of the lectin pathway C3 convertase [25]. Finally, complement-fixing IgM anti-ACE2 and IgG and IgM anti-SARS-CoV-2 antibodies directed against the viral N and S proteins, trigger activation of the classical pathway [19,22,26].…”