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Hidden fraction of Polish population immune to SARS-CoV-2 in May 2021.
- Source :
-
PloS one [PLoS One] 2022 Feb 03; Vol. 17 (2), pp. e0253638. Date of Electronic Publication: 2022 Feb 03 (Print Publication: 2022). - Publication Year :
- 2022
-
Abstract
- Population immunity (herd immunity) to SARS-CoV-2 derives from two sources: vaccinations or cases of infection with the virus. Infections can be diagnosed as COVID-19 and registered, or they can be asymptomatic, oligosymptomatic, or even full-blown but undiagnosed and unregistered when patients recovered at home. Estimation of population immunity to SARS-CoV-2 is difficult and remains a subject of speculations. Here we present a population screening for SARS-CoV-2 specific IgG and IgA antibodies in Polish citizens (N = 501) who had never been positively diagnosed with or vaccinated against SARS-CoV-2. Serum samples were collected in Wrocław (Lower Silesia) on 15th and 22nd May 2021. Sera from hospitalized COVID-19 patients (N = 22) or from vaccinated citizens (N = 14) served as positive controls. Sera were tested with Microblot-Array COVID-19 IgG and IgA (quantitative) that contain specific SARS-CoV-2 antigens: NCP, RBD, Spike S2, E, ACE2, PLPro protein, and antigens for exclusion cross-reactivity with other coronaviruses: MERS-CoV, SARS-CoV, HCoV 229E Np, HCoV NL63 Np. Within the investigated population of healthy individuals who had never been positively diagnosed with or vaccinated against SARS-CoV-2, we found that 35.5% (178 out of 501) were positive for SARS-CoV-2-specific IgG and 52.3% (262 out of 501) were positive for SARS-CoV-2-specific IgA; 21.2% of the investigated population developed virus-specific IgG or IgA while being asymptomatic. Anti-RBD IgG, which represents virus-neutralizing potential, was found in 25.6% of individuals (128 out of 501). These patients, though positive for anti-SARS-CoV-2 antibodies, cannot be identified in the public health system as convalescents due to undiagnosed infections, and they are considered unaffected by SARS-CoV-2. Their contribution to population immunity against COVID-19 should however be considered in predictions and modeling of the COVID-19 pandemic. Of note, the majority of the investigated population still lacked anti-RBD IgG protection (74.4%); thus vaccination against COVID-19 is still of the most importance for controlling the pandemic.<br />Competing Interests: The authors have declared that no competing interests exist.
- Subjects :
- Adolescent
Adult
Aged
Antibodies, Viral blood
Antibodies, Viral immunology
Antigens, Viral immunology
COVID-19 blood
COVID-19 prevention & control
Cross Reactions
Female
Humans
Immunoglobulin A blood
Immunoglobulin A immunology
Immunoglobulin G blood
Immunoglobulin G immunology
Male
Middle Aged
Poland epidemiology
Treatment Outcome
Young Adult
Asymptomatic Infections epidemiology
COVID-19 epidemiology
COVID-19 immunology
COVID-19 Vaccines therapeutic use
Immunity, Herd
Pandemics prevention & control
SARS-CoV-2 immunology
Vaccination methods
Subjects
Details
- Language :
- English
- ISSN :
- 1932-6203
- Volume :
- 17
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- PloS one
- Publication Type :
- Academic Journal
- Accession number :
- 35113873
- Full Text :
- https://doi.org/10.1371/journal.pone.0253638