tetano
Editor, Senior Moderator
PLoS One
. 2022 Feb 3;17(2):e0253638.
doi: 10.1371/journal.pone.0253638. eCollection 2022.
Hidden fraction of Polish population immune to SARS-CoV-2 in May 2021
Wiktoria Budziar[SUP] 1 [/SUP], Katarzyna Gembara[SUP] 1 2 [/SUP], Marek Harhala[SUP] 1 2 [/SUP], Aleksander Szymczak[SUP] 1 2 [/SUP], Natalia Jędruchniewicz[SUP] 1 [/SUP], Krzysztof Baniecki[SUP] 3 [/SUP], Aleksandra Pikies[SUP] 3 [/SUP], Artur Nahorecki[SUP] 3 [/SUP], Agnieszka Hoffmann[SUP] 1 [/SUP], Amelia Kardaś[SUP] 1 [/SUP], Alina Szewczyk-Dąbrowska[SUP] 1 [/SUP], Tomasz Klimek[SUP] 1 [/SUP], Zuzanna Kaźmierczak[SUP] 1 2 [/SUP], Wojciech Witkiewicz[SUP] 1 [/SUP], Kamil Barczyk[SUP] 3 [/SUP], Krystyna Dąbrowska[SUP] 1 2 [/SUP]
Affiliations
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.
. 2022 Feb 3;17(2):e0253638.
doi: 10.1371/journal.pone.0253638. eCollection 2022.
Hidden fraction of Polish population immune to SARS-CoV-2 in May 2021
Wiktoria Budziar[SUP] 1 [/SUP], Katarzyna Gembara[SUP] 1 2 [/SUP], Marek Harhala[SUP] 1 2 [/SUP], Aleksander Szymczak[SUP] 1 2 [/SUP], Natalia Jędruchniewicz[SUP] 1 [/SUP], Krzysztof Baniecki[SUP] 3 [/SUP], Aleksandra Pikies[SUP] 3 [/SUP], Artur Nahorecki[SUP] 3 [/SUP], Agnieszka Hoffmann[SUP] 1 [/SUP], Amelia Kardaś[SUP] 1 [/SUP], Alina Szewczyk-Dąbrowska[SUP] 1 [/SUP], Tomasz Klimek[SUP] 1 [/SUP], Zuzanna Kaźmierczak[SUP] 1 2 [/SUP], Wojciech Witkiewicz[SUP] 1 [/SUP], Kamil Barczyk[SUP] 3 [/SUP], Krystyna Dąbrowska[SUP] 1 2 [/SUP]
Affiliations
- PMID: 35113873
- DOI: 10.1371/journal.pone.0253638
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.