Observational studyEuropean journal of immunology2022
Longitudinal SARS-CoV-2 seroprevalence in Portugal and antibody maintenance 12 months after infection.
Observational study in European journal of immunology, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 17 papers, 2 of them syntheses that pooled it.
What it found
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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.
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Who cites it
17 citing papers in PubMed, 2 syntheses or guidelines pooled it, 38 citations in OpenAlex.
- Differential COVID-19 infection rates in children, adults, and elderly: Systematic review and meta-analysis of 38 pre-vaccination national seroprevalence studies.Journal of global health · 2023Pooled it
- Age-stratified infection fatality rate of COVID-19 in the non-elderly population.Environmental research · 2023Pooled it
- Immunogenicity, Effectiveness, and Safety of Inactivated Virus (CoronaVac) Vaccine in a Two-Dose Primary Protocol and BNT162b2 Heterologous Booster in Brazil (Immunita-001): A One Year Period Follow Up Phase 4 Study.Frontiers in immunology · 2022Trial
- Serological responses to SARS-CoV-2 in urban and rural Ghana: Antibody waning and implications for long-term population immunity.PloS one · 2026Article
- Pre-existing IgG antibodies to HCoVs NL63 and OC43 Spike increased during the pandemic and after COVID-19 vaccination.Heliyon · 2025Article
- Association between COVID-19 and the incidence of type 1 diabetes in Portugal - a registry study.BMC endocrine disorders · 2024Article
- Impact of Prior COVID-19 Immunization and/or Prior Infection on Immune Responses and Clinical Outcomes.Viruses · 2024Review
- Humoral and T cell responses to SARS-CoV-2 reveal insights into immunity during the early pandemic period in Pakistan.BMC infectious diseases · 2023Article
- Long-term humoral and cellular immunity after primary SARS-CoV-2 infection: a 20-month longitudinal study.BMC immunology · 2023Article
- Reversed urban-rural gradient in COVID-19 seroprevalence and related factors in a nationally representative survey, Poland, 29 March to 14 May 2021.Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin · 2023Article
- Educational intervention for the main caregiver of primiparous women to promote breastfeeding and the association between prolactin and nutritional parameters.Journal of global health · 2023Observational
- Eight Months of Serological Follow-Up of Anti-SARS-CoV-2 Antibodies in France: A Study among an Adult Population.International journal of environmental research and public health · 2022Article
- Protocol of the Luebeck longitudinal investigation of SARS-CoV-2 infection (ELISA) study - a prospective population-based cohort study.BMC public health · 2022Article
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- IgG antibodies to SARS-CoV-2 in asymptomatic blood donors at two time points in Karachi.PloS one · 2022Article
- Seroprevalence of anti-SARS-CoV-2 antibodies 6 months into the vaccination campaign in Geneva, Switzerland, 1 June to 7 July 2021.Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin · 2021Article
Corrections and comments
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Authors and funding
19 authors at 3 institutions in 2 countries.
Funding
Abstract
During the COVID-19 pandemic, Portugal has experienced three distinct SARS-CoV-2 infection waves. We previously documented the prevalence of SARS-CoV-2 immunity, measured by specific antibodies, in September 2020, 6 months after the initial moderate wave. Here, we show the seroprevalence changes 6 months later, up to the second week of March 2021, shortly following the third wave, which was one of the most severe in the world, and 2 months following the start of the vaccination campaign. A longitudinal epidemiological study was conducted, with a stratified quota sample of the Portuguese population. Serological testing was performed, including ELISA determination of antibody class and titers. The proportion of seropositives, which was 2.2% in September 2020, rose sharply to 17.3% (95% CI: 15.8-18.8%) in March 2021. Importantly, circulating IgG and IgA antibody levels were very stable 6 months after the initial determination and up to a year after initial infection, indicating long-lasting infection immunity against SARS-CoV-2. Moreover, vaccinated people had higher IgG levels from 3 weeks post-vaccination when compared with previously infected people at the same time post-infection.
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Registered trials
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.