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DİNÇ, HARİKA ÖYKÜ

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HARİKA ÖYKÜ
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Subject: Neutralizing antibody ×

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    PublicationOpen Access
    Waning immunity to inactive SARS-CoV-2 vaccine in healthcare workers: booster required
    (2022-03-01T00:00:00Z) BALKAN, İLKER İNANÇ; DİNÇ, HARİKA ÖYKÜ; CAN, GÜNAY; KARAALİ, RIDVAN; Ozbey, Dogukan; ÇAĞLAR, BİLGE; BEYTUR, AYŞE NUR; KESKİN, ELİF; BUDAK, Beyhan; Aydogan, Okan; METE, BİLGÜL; ERGİN, SEVGİ; KOCAZEYBEK, BEKİR SAMİ; SALTOĞLU, NEŞE; DİNÇ, HARİKA ÖYKÜ
    Aims Despite high vaccination rates, increasing case numbers continue to be reported with the identification of new variants of concern, and the issue of durability of the vaccine-induced immune response remains hot topic. Real-life data regarding time-dependent immunogenicity of inactivated COVID-19 vaccines are scarce. We aimed to investigate the changes in the antibody at the different times after the second dose of the CoronaVac vaccine. Methods The study included 175 HCWs vaccinated with inactive CoronaVac (Sinovac Life Sciences, China) SARS-CoV-2 vaccine in two doses. Anti-spike/RBD IgG levels were measured first, third, and sixth months after the second dose. Chemiluminescent microparticle immunoassay (IgG II Quant test, Abbott, USA), which is 100% compatible with plaque reduction neutralization test, was used. Results Mean age of the participants was 38 +/- 11.23 years (range between 22 and 66) of whom 119 (63.9%) were female, and 56 (32%) were male. Dramatic reductions were demonstrated in median antibody levels particularly in the infection-naive group, comprising 138 HCWs compared to those with prior history of COVID-19 infection (n = 37) (p < 0.001). There was no difference between the two groups in terms of age, gender, blood groups, BMI, and comorbid diseases. Conclusions While antibody positivity remained above 90% in the 6th month after two doses of inactivated vaccine in HCWs, the median titers of neutralizing antibodies decreased rapidly. The decrease was more rapid and significant in those with no history of prior COVID-19 infection. In this critical phase of the pandemic, where we are facing the dominance of the Omicron variant after Delta, booster doses have become vital.
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    PublicationOpen Access
    Anti-SARS-CoV-2 IgG and Neutralizing Antibody Levels in Patients with Past COVID-19 Infection: A Longitudinal Study.
    (2022-04-05T00:00:00Z) Dinç, HARİKA ÖYKÜ; Demirci, Mehmet; Özdemir, Yusuf Emre; Sirekbasan, Serhat; Aktaş, Ayse Nur; Karaali, Rıdvan; Tuyji Tok, Yeşim; Özbey, Doğukan; Akçin, Rüveyda; Gareayaghi, Nesrin; Kuşkucu, Mert Ahmet; Midilli, Kenan; Aygün, Gökhan; Sarıbaş, Suat; Kocazeybek, Bekir; DİNÇ, HARİKA ÖYKÜ
    Background: Monitoring the longevity of immunoglobulin G (IgG) responses following severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections is vital to understanding the role of antibodies in preventing infection. Aims: To determine the quantitative IgG responses specific to the Spike-S1 (S1) receptor-binding domain (S1/RBD) region of the virus in serum samples taken between 4 weeks and 7 months after polymerase chain reaction (PCR) positivity in patients who are diagnosed with coronavirus disease-2019 (COVID-19). Study design: A longitudinal study. Methods: This study included 113 patients with a clinical and molecular diagnosis of COVID-19. The first and second serum samples were taken 1 and 7 months, respectively, after the PCR positivity. S1/RBD-specific IgG antibody response was assayed using anti-SARS-CoV- 2 QuantiVac ELISA (IgG) kit (Euroimmun, Lübeck, Germany). The neutralizing antibodies were investigated in 57 patients whose IgG test results were above the cut-off value. Results: In 57 patients with SARS-CoV-2 IgG, the anti-SARS-CoV-2 IgG quantitative antibody levels significantly decreased after 7 months (Z = −2.197, p = 0.028). A correlation was detected between the anti-SARS-CoV-2 IgG and nAb percent inhibition (IH%) levels detected in 1 month (rs = 0.496, p < 0.001), but without significant correlation in serum samples taken on 7 months. The nAb IH% levels of the first and second were compared for COVID-19 severity and revealed no statistical difference (p = 0.256). In the second serum sample, the nAb IH%s of patients with moderate COVID-19 showed a statistically significant difference from patients with mild COVID-19 (p = 0.018), but without significant differences between severe and moderate or mild COVID-19. Conclusion: SARS-CoV-2 quantitative IgG antibody titers are significantly reduced at long-term follow-up (> 6 months). Due to the limited information on seroconversion, comprehensive studies should be conducted for long-term follow-up of the immune response against SARS-CoV-2.