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. 2023 Apr 20;10(5):ofad216.
doi: 10.1093/ofid/ofad216. eCollection 2023 May.

Large Diffusion of Severe Acute Respiratory Syndrome Coronavirus 2 After the Successive Epidemiological Waves, Including Omicron, in Guinea and Cameroon: Implications for Vaccine Strategies

Mamadou Saliou Kalifa Diallo  1   2 , Marie Amougou-Atsama  3 , Ahidjo Ayouba  2 , Cece Kpamou  1 , Eric Donald Mimbe Taze  4 , Guillaume Thaurignac  2 , Haby Diallo  1 , Nadine Boutgam Lamare  5 , Julie Bouillin  2 , Abdoul Karim Soumah  1 , Sébastien Awono Noah  4 , Emilande Guichet  2 , Alpha Kabinet Keita  1   2 , Marie Varloteaux  4 , Martine Peeters  2 , Anne-Cécile Zoung-Kanyi Bissek  3   6 , Abdoulaye Toure  1 , Eric Delaporte  2 , Charles Kouanfack  4   5   7
Affiliations

Large Diffusion of Severe Acute Respiratory Syndrome Coronavirus 2 After the Successive Epidemiological Waves, Including Omicron, in Guinea and Cameroon: Implications for Vaccine Strategies

Mamadou Saliou Kalifa Diallo et al. Open Forum Infect Dis. .

Abstract

Background: We aimed to estimate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence among the general population in Conakry, Guinea and Yaounde, Cameroon after the coronavirus disease 2019 Omicron wave.

Methods: We conducted population-based, age-stratified seroprevalence surveys in Conakry and Yaounde (May and June 2022). We collected demographic and epidemiologic information and dried blood spot samples that were tested for SARS-CoV-2 immunoglobulin G (IgG) antibodies using recombinant nucleocapsid and spike proteins with Luminex technology.

Results: Samples were obtained from 1386 and 1425 participants in Guinea and Cameroon, respectively. The overall age-standardized SARS-CoV-2 IgG seroprevalence against spike and nucleocapsid proteins was 71.57% (95% confidence interval [CI], 67.48%-75.33%) in Guinea and 74.71% (95% CI, 71.99%-77.25%) in Cameroon. Seroprevalence increased significantly with age categories. Female participants were more likely than male participants to be seropositive. The seroprevalence in unvaccinated participants was 69.6% (95% CI, 65.5%-73.41%) in Guinea and 74.8% (95% CI, 72.04%-77.38%) in Cameroon. In multivariate analysis, only age, sex, and education were independently associated with seropositivity.

Conclusions: These findings show a high community transmission after the different epidemiological waves including Omicron, especially among people aged >40 years. In addition, our results suggest that the spread of SARS-CoV-2 has been underestimated as a significant proportion of the population has already contracted the virus and that vaccine strategies should focus on vulnerable populations.

Keywords: Cameroon; Guinea; SARS-CoV-2; population-based survey; seroprevalence.

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Conflict of interest statement

Conflict of interest. No reported conflicts of interest for all authors.

Figures

Figure 1.
Figure 1.
Weighted and age-standardized seroprevalence of severe acute respiratory syndrome coronavirus 2 antibodies in 4 successive population-based surveys, Conakry, Guinea. Dots represent the estimated prevalence and bars represent 95% confidence intervals.
Figure 2.
Figure 2.
Weighted and age-standardized seroprevalence of severe acute respiratory syndrome coronavirus 2 antibodies in 3 successive population-based surveys, Yaounde, Cameroon. Dots represent the estimated prevalence and bars represent 95% confidence intervals.
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