Characterizing the evolving SARS-CoV-2 seroprevalence in urban and rural Malawi between February 2021 and April 2022: A population-based cohort study.
Int J Infect Dis
; 137: 118-125, 2023 Dec.
Article
en En
| MEDLINE
| ID: mdl-38465577
ABSTRACT
OBJECTIVES:
This study aimed to investigate the changing SARS-CoV-2 seroprevalence and associated health and sociodemographic factors in Malawi between February 2021 and April 2022.METHODS:
In total, four 3-monthly serosurveys were conducted within a longitudinal population-based cohort in rural Karonga District and urban Lilongwe, testing for SARS-CoV-2 S1 immunoglobulin (Ig)G antibodies using an enzyme-linked immunosorbent assay. Population seroprevalence was estimated in all and unvaccinated participants. Bayesian mixed-effects logistic models estimated the odds of seropositivity in the first survey, and of seroconversion between surveys, adjusting for age, sex, occupation, location, and assay sensitivity/specificity.RESULTS:
Of the 2005 participants (Karonga, n = 1005; Lilongwe, n = 1000), 55.8% were female and median age was 22.7 years. Between Surveys (SVY) 1 and 4, population-weighted SARS-CoV-2 seroprevalence increased from 26.3% to 89.2% and 46.4% to 93.9% in Karonga and Lilongwe, respectively. At SVY4, seroprevalence did not differ by COVID-19 vaccination status in adults, except for those aged 30+ years in Karonga (unvaccinated 87.4%, 95% credible interval 79.3-93.0%; two doses 98.1%, 94.8-99.5%). Location and age were associated with seroconversion risk. Individuals with hybrid immunity had higher SARS-CoV-2 seropositivity and antibody titers, than those infected.CONCLUSION:
High SARS-CoV-2 seroprevalence combined with low morbidity and mortality indicate that universal vaccination is unnecessary at this stage of the pandemic, supporting change in national policy to target at-risk groups.Palabras clave
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
COVID-19
Límite:
Adult
/
Female
/
Humans
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Male
País/Región como asunto:
Africa
Idioma:
En
Revista:
Int J Infect Dis
Asunto de la revista:
DOENCAS TRANSMISSIVEIS
Año:
2023
Tipo del documento:
Article
País de afiliación:
Malawi