Evidence map›Paper›PMID 42093108›Full record

ArticleImmunity, inflammation and disease2026

Widespread SARS-CoV-2 Transmission Despite Limited Reported Cases and Clinical Disease: Exploring the Role of Pre-Existing Humoral Immunity to SARS-CoV-2 in Eastern Sierra Leone.

Robert J Samuels, Nell G Bond, Ibrahim Sumah, Donald S Grant, Mohamed S Kamara, Lydia Bazzano, Camilo Fernandez, Rodrigo Borrega, Sruti Chandra, Celia R Glezer and 2 more

Abstract read
In one paragraph

Article in Immunity, inflammation and disease, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

12 authors.

Robert J SamuelsKenema Government Hospital, Kenema, Sierra Leone.ORCID https://orcid.org/0009-0003-7000-4218
Nell G BondTulane University School of Medicine, New Orleans, Louisiana, USA.ORCID https://orcid.org/0000-0002-4996-4025
Ibrahim SumahKenema Government Hospital, Kenema, Sierra Leone.
Donald S GrantKenema Government Hospital, Kenema, Sierra Leone.
Mohamed S KamaraKenema Government Hospital, Kenema, Sierra Leone.
Lydia BazzanoTulane University Celia Scott Weatherhead School of Public Health and Tropical Medicine, New Orleans, Louisiana, USA.
Camilo FernandezTulane University School of Medicine, New Orleans, Louisiana, USA.
Rodrigo BorregaTulane University School of Medicine, New Orleans, Louisiana, USA.
Sruti ChandraTulane University School of Medicine, New Orleans, Louisiana, USA.
Celia R GlezerTulane University School of Medicine, New Orleans, Louisiana, USA.
John S SchieffelinTulane University School of Medicine, New Orleans, Louisiana, USA.
Troy D MoonTulane University School of Medicine, New Orleans, Louisiana, USA.

Funding

West Africa - Tulane University Laboratory Training Fellowship Supplement for Partnership for Research in Emerging Viral Infections Sierra Leone (PREVSL) U2RTW011248U2RTW011248 · FIC · VANDERBILT UNIVERSITY MEDICAL CENTER · PI MOON, D. TROY · 2019 to 2023
$1.3M
FIC NIH HHS U2R TW011248Fogarty International Center of the National Institutes of Health U2RTW011248Tulane Center of Excellence in Emerging and Reemerging Infectious Diseases (CEERID)
6 · The paper itself

Abstract

backgroundSince December 2019, SARS-CoV-2 has infected over 700 million people and caused > 7 million deaths. While much of the global north was severely affected, sub-Saharan Africa was relatively spared. Possible reasons include a younger population, fewer comorbidities, and pre-existing immunity. Here, we expand on previous work through a cohort of 306 subjects, with samples drawn pre-pandemic, intra-pandemic, and post-vaccination.

methodsWe assessed antibody reactivity to seasonal coronaviruses, emerging coronaviruses, and SARS-CoV-2 spike (S), nucleoprotein (N), and receptor binding domain (RBD) proteins in a longitudinal cohort. Antibody neutralization was measured using a pseudovirus neutralization assay.

resultsOur data show that 16%-20% of pre-pandemic samples had reactivity to SARS-CoV-2 N protein. Further, we noted relatively high reactivity to SARS-CoV-2 RBD (~31%), and low, but notable, seropositivity to SARS-CoV-2 S protein (3.3%-3.4%). We additionally found a significant jump in seropositivity to all SARS-CoV-2 proteins by March 2022 (intra-pandemic), and high levels of neutralization in the intra-pandemic samples compared to pre-pandemic samples. A boosting effect on SARS-CoV-2 Spike was observed after vaccination.

conclusionsWe report widespread circulation of SARS-CoV-2 in eastern Sierra Leone by March 2022 despite low national reporting. Furthermore, we provide evidence of pre-existing humoral immunity to SARS-CoV-2 as compared to US controls. This may have resulted in less severe disease, less COVID-19 testing and the apparent lack of clinical cases. Finally, we show boosting of SARS-CoV-2 Spike following vaccination. Studies comparing HLA type between symptomatic and asymptomatic cases are being planned. Studies to better characterize cellular immunity from pre-pandemic timepoints should also be prioritized.

Indexed as

Antibodies, ViralCOVID-19Immunity, HumoralSARS-CoV-2AdolescentAdultAgedAntibodies, NeutralizingFemaleHumansMaleMiddle AgedSierra LeoneSpike Glycoprotein, CoronavirusYoung AdultAntibodies, NeutralizingAntibodies, ViralSpike Glycoprotein, Coronavirusspike protein, SARS-CoV-2COVID‐19cross‐reactivityhuman coronaviruspre‐existing immunitySARS‐CoV‐2Sierra Leonesub‐Saharan Africa

Identifiers

PMID42093108
PMCPMC13149761

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.