Neutralizing antibody titers six months after Comirnaty vaccination: kinetics and comparison with SARS-CoV-2 immunoassays

Author(s):  
Andrea Padoan ◽  
Chiara Cosma ◽  
Francesco Bonfante ◽  
Foscarina della Rocca ◽  
Francesco Barbaro ◽  
...  

Abstract Objectives mRNA vaccines, including Comirnaty (BNT162b2 mRNA, BioNTech-Pfizer), elicit high IgG and neutralizing antibody (NAb) responses after the second dose, but the progressive decrease in serum antibodies against SARS-CoV-2 following vaccination have raised questions concerning long-term immunity, decreased antibody levels being associated with breakthrough infections after vaccination, prompting the consideration of booster doses. Methods A total number of 189 Padua University-Hospital healthcare workers (HCW) who had received a second vaccine dose were asked to collect serum samples for determining Ab at 12 (t12) and 28 (t28) days, and 6 months (t6m) after their first Comirnaty/BNT162b2 inoculation. Ab titers were measured with plaque reduction neutralization test (PRNT), and three chemiluminescent immunoassays, targeting the receptor binding domain (RBD), the trimeric Spike protein (trimeric-S), and surrogate viral neutralization tests (sVNT). Results The median percentages (interquartile range) for decrease in antibodies values 6 months after the first dose were 86.8% (67.1–92.8%) for S-RBD IgG, 82% (58.6–89.3%) for trimeric-S, 70.4% (34.5–86.4%) for VNT-Nab, 75% (50–87.5%) for PRNT50 and 75% (50–93.7%) for PRNT90. At 6 months, neither PRNT titers nor VNT-Nab and S-RBD IgG bAb levels correlated with age (p=0.078) or gender (p=0.938), while they were correlated with previous infection (p<0.001). Conclusions After 6 months, a method-independent reduction of around 90% in anti-SARS-CoV-2 antibodies was detected, while no significant differences were found between values of males and females aged between 24 and 65 years without compromised health status. Further efforts to improve analytical harmonization and standardization are needed.

2021 ◽  
Author(s):  
Calvin P Sjaarda ◽  
Emily Moslinger ◽  
Kyla Tozer ◽  
Robert I Colautti ◽  
Samira Kheitan ◽  
...  

Background. Antibody responses to SARS-CoV-2 can be observed as early as 14 days post- infection, but little is known about the stability of antibody levels over time. Here we evaluate the long-term stability of anti-SARS-CoV-2 IgG antibodies following infection in 402 adult donors. Methods. We performed a multi-centre study carried out at Plasma Donor Centres in the city of Heidelberg (Plasmazentrum Heidelberg, Germany) and Munich (Plasmazentrum M&uumlnchen, Germany). We present anti-S/N and anti-N IgG antibody levels in prospective serum samples collected up to 403 days post recovery from SARS-CoV-2 infected individuals. Results: The cohort includes 402 adult donors (185 female, 217 male; 17 - 68 years of age) where anti-SARS-CoV-2 IgG levels were measured in plasma samples collected between 18- and 403-days post SARS-CoV-2 infection. A linear mixed effects model demonstrated IgG decay rates that decrease over time (χ2=176.8, p<0.00001) and an interaction of time*age (χ2=10.0, p<0.005)), with those over 60+ years showing the highest baseline IgG levels and the fastest rate of IgG decay. Baseline viral neutralization assays demonstrated that serum IgG levels correlated with in vitro neutralization capacity in 91% of our cohort. Conclusion. Long-term antibody levels and age-specific antibody decay rates suggest the potential need for age-specific vaccine booster guidelines to ensure long term vaccine protection against SARS-CoV-2 infection.


2021 ◽  
Author(s):  
Sabrina E Racine-Brzostek ◽  
Mohsen Karbaschi ◽  
Christian Gaebler ◽  
P J Klasse ◽  
Jim Yee ◽  
...  

Abstract Background Low initial SARS-CoV-2 antibody titers dropping to undetectable levels within months after infection have raised concerns over long term immunity. Both the antibody levels and avidity of the antibody-antigen interaction should be examined to understand the quality of the antibody response. Methods A testing-on-a-probe “plus” panel (TOP-Plus) was developed, which included a newly developed avidity assay built into the previously described SARS-CoV-2 TOP assays that measured total antibody (TAb), surrogate neutralizing antibody (SNAb), IgM and IgG on a versatile biosensor platform. TAb and SNAb levels were compared with avidity in previously infected individuals at 1.3 and 6.2 months post-infection in paired samples from 80 COVID-19 patients. Sera from SARS-CoV-2 vaccinated individuals were also evaluated for antibody avidity. Results The newly designed avidity assay in this TOP panel correlated well with a reference Bio-Layer Interferometry avidity assay (r=0.88). The imprecision of the TOP avidity assay was less than 10%. Although TAb and neutralization activity (by SNAb) decreased between 1.3 and 6.2 months post-infection, the antibody avidity increased significantly (P &lt; 0.0001). Antibody avidity in 10 SARS-CoV-2 vaccinated individuals (median 28 days post-vaccination) was comparable to the measured antibody avidity in infected individuals (median 26 days post-infection). Conclusion This highly precise and versatile TOP-Plus panel with the ability to measure SARS-CoV-2 TAb, SNAb, IgG and IgM antibody levels and avidity of individual sera on one sensor can become a valuable asset in monitoring not only SARS-CoV-2-infected patients, but also the status of individuals’ COVID-19 vaccination response.


Author(s):  
Füsun Can ◽  
Zeynep Ece Kuloğlu ◽  
Rojbin El ◽  
Gülen Esken ◽  
Yeşim Tok ◽  
...  

Objective: There is a need for the immunogenicity of different boosters after widely used inactivated vaccine regimens. We aimed to determine the effects of BNT162b2 and CoronaVac boosters on the humoral and cellular immunity of individuals who had two doses of CoronaVac vaccination. Methods: The study was conducted in three centers (Koc University Hospital, Istanbul University Cerrahpasa Hospital, and Istanbul University, Istanbul Medical School Hospital) in Istanbul. Individuals who had two doses of CoronaVac and no history of COVID-19 were included. The baseline blood samples were collected three to five months after two doses of CoronaVac. Follow-up samples were taken one and three months after third doses of CoronaVac or one dose of mRNA BNT162b2 boosters. Neutralizing antibody titers were detected by plaque reduction assay. T cell responses were evaluated by Elispot assay and flow cytometry. Results: We found a 3.38-fold increase in neutralizing antibody titers (Geometric Mean Titer [GMT], 78.69) one month after BNT162b2 booster and maintained at the three months (GMT, 80). However, in the CoronaVac group, significantly lower GMTs than BNT162b2 after 1 month and 3 months (21.44 and 28.44, respectively) indicated the weak immunogenicity of the CoronaVac booster (p<0.001). In the ELISpot assay, IL-2 levels after BNT162b2 were higher than baseline and CoronaVac booster (p<0.001) and IFN-γ levels were significantly higher than baseline (P<0.001). The CD8+CD38+CD69+ and CD4+CD38+CD69+ T cells were stimulated significantly at the 3 month of the BNT162b2 boosters. Conclusion: The neutralizing antibody levels after three months of the BNT162b2 booster were higher than the antibody levels after CoronaVac. On the other hand, specific T cells might contribute to immune protection. By considering the waning immunity, we suggest a new booster dose with BNT162b2 for the countries that already have two doses of primary CoronaVac regimens.


Author(s):  
Sabrina E. Racine-Brzostek ◽  
Mohsen Karbaschi ◽  
Christian Gaebler ◽  
P.J. Klasse ◽  
Jim Yee ◽  
...  

AbstractBackgroundThere is a concern that low initial SARS-CoV-2 antibody titers in individuals may drop to undetectable levels within months after infection. Although this may raise concerns over long term immunity, both the antibody levels and avidity of the antibody-antigen interaction should be examined to understand the quality of the antibody response.MethodsA testing-on-a-probe “plus” panel (TOP-Plus) was developed, which included a newly developed avidity assay built into the previously described SARS-CoV-2 TOP assays that measured total antibody (TAb), surrogate neutralizing antibody (SNAb), IgM and IgG on a versatile biosensor platform. TAb and SNAb levels were compared with avidity in previously infected individuals at 1.3 and 6.2 months post-infection in paired samples from 80 COVID-19 patients.ResultsThe newly designed avidity assay in this TOP panel correlated well with a reference Bio-Layer Interferometry avidity assay (R=0.88). The imprecision of the TOP avidity assay was less than 9%. Although TAb and neutralization activity (by SNAb) decreased between 1.3 and 6.2 months post infection, the antibody avidity increased significantly (P < 0.0001).ConclusionThis highly precise and versatile TOP-Plus panel with the ability to measure SARS-CoV-2 TAb, SNAb, IgG and IgM antibody levels and avidity of individual sera on one sensor can become a valuable asset in monitoring not only SARS-CoV-2-infected patients, but also the status of individuals’ COVID-19 vaccination response.


2021 ◽  
Vol 12 ◽  
Author(s):  
Atsushi Goto ◽  
Hirofumi Go ◽  
Kei Miyakawa ◽  
Yutaro Yamaoka ◽  
Norihisa Ohtake ◽  
...  

Objective: There is scarce evidence regarding the long-term persistence of neutralizing antibodies among coronavirus disease 2019 (COVID-19) survivors. This study determined neutralizing antibody titers (NT50) and antibodies against spike protein (SP) or nucleocapsid protein (NP) antigens approximately 6 months after the diagnosis of COVID-19.Methods: COVID-19 survivors in Japan were recruited. Serum samples and data related to patients’ characteristics and COVID-19 history were collected. NT50 and titers of antibodies against NP and SP antigens were measured at 20–32 weeks after the first positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test results. Factors associated with NT50 were identified using the multivariable linear regression and the correlations among NT50 and titers of immunoglobulin G (IgG) and total immunoglobulins (Igs) against NP and SP were assessed by Spearman’s correlation.Results: Among 376 participants (median [range] days after testing positive for SARS-CoV-2, 180 (147–224); median [range] years of age, 50 (20–78); 188 [50%] male), most tested positive for NT50 (n = 367, 98%), SP-IgG (n = 344, 91%), SP-total Ig (n = 369, 98%), NP-IgG (n = 314, 84%), and NP-total Ig (n = 365, 97%). Regression analysis indicated that higher BMI, fever, and the requirement of mechanical ventilation or extracorporeal membrane oxygenation were significantly associated with higher NT50. Anti-SP antibodies correlated moderately with NT50 (Spearman’s correlation: 0.63 for SP IgG; 0.57 for SP-total Ig), while the correlation was weak for anti-NP antibodies (0.37 for NP IgG; 0.32 for NP-total Ig).Conclusions: Most COVID-19 survivors had sustained neutralizing antibodies and tested positive for SP-total Ig and NP-total Ig approximately 6 months after infection.


Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1347
Author(s):  
Claudia Maria Trombetta ◽  
Serena Marchi ◽  
Simonetta Viviani ◽  
Alessandro Manenti ◽  
Linda Benincasa ◽  
...  

The recent spreading of new SARS-CoV-2 variants, carrying several mutations in the spike protein, could impact immune protection elicited by natural infection or conferred by vaccination. In this study, we evaluated the neutralizing activity against the viral variants that emerged in the United Kingdom (B.1.1.7), Brazil (P.1), and South Africa (B.1.351) in human serum samples from hospitalized patients infected by SARS-CoV-2 during the first pandemic wave in Italy in 2020. Of the patients studied, 59.5% showed a decrease (≥2 fold) in neutralizing antibody titer against B.1.1.7, 83.3% against P.1, and 90.5% against B.1.351 with respect to the original strain. The reduction in antibody titers against all analyzed variants, and in particular P.1 and B.1.351, suggests that previous symptomatic infection might be not fully protective against exposure to SARS-CoV-2 variants carrying a set of relevant spike mutations.


2007 ◽  
Vol 15 (2) ◽  
pp. 297-302 ◽  
Author(s):  
Olga Sánchez Negrette ◽  
Fernando J. Sánchez Valdéz ◽  
Carlos D. Lacunza ◽  
María Fernanda García Bustos ◽  
María Celia Mora ◽  
...  

ABSTRACT Serological tests are the main laboratory procedures used for diagnosis during the indeterminate and chronic stages of Chagas' disease. A serological regression to negativity is the main criterion used to define parasitological cure in treated patients. The aim of this work was to monitor the individual specificities of antibody levels for 3 years posttreatment in 18 adult patients. Conventional serological techniques (hemagglutination assays and enzyme-linked immunosorbent assay [ELISA]) were modified by using recombinant antigens to detect early markers of treatment effectiveness. For this purpose, serum samples were taken before and during treatment and every 6 months after treatment for at least 3 years. When hemagglutination assays were used, a decrease in antibody levels was observed in only one patient. When ELISA with serum dilutions was used, antibody clearance became much more apparent: in 77.7% (14/18) of the patients, antibody titers became negative with time. This was observed at serum dilutions of 1/320 and occurred between the 6th and the 30th months posttreatment. The immune response and the interval for a serological regression to negativity were different for each patient. For some of the recombinant antigens, only 50% (9/18) of the patients reached the serological regression to negativity. Recombinant antigen 13 might be a good marker of treatment effectiveness, since 66.6% (six of nine) of the patients presented with an early regression to negativity for specific antibodies to this antigen (P = 0.002).


2017 ◽  
Vol 47 (10) ◽  
Author(s):  
Mathias Martins ◽  
João Motta de Quadros ◽  
Eduardo Furtado Flores ◽  
Rudi Weiblen

ABSTRACT: The antibody response to rabies virus (RABV) induced by commercial vaccines in heifers was investigated. For this, 84 heifers were vaccinated twice (30 days interval) with each of four vaccines (G1 = 14 animals; G2 = 24; G3 = 22 and G4 = 24) and received a booster vaccination 360 days later. Serum samples collected at different intervals after vaccination and 30 days after booster were submitted to a virus neutralizing (VN) assay for RABV antibodies. Thirty days after the second vaccine dose, 92% of the immunized animals presented VN titers ≥0.5UI/mL (geometric medium titers [GMT] 1.7 to 3.8UI/mL). At the day of the booster (360 days post-vaccination); however, the percentage of animals harboring antibody titers ≥0.5UI/mL had dropped to 31% (0-80% of the animals, depending on the vaccine), resulting in lower GMT (0.1 to 0.6UI/mL). Booster vaccination at day 360 resulted in a detectable anamnestic response in all groups, resulting in 83% of animals (65 to 100%) harboring VN titers ≥0.5UI/mL thirty days later (GMT 0.6 to 4.3UI/mL). These results indicated that these vaccines were able to induce an adequate anti-RABV response in all animals after prime vaccination (and after booster as well). However, the titers decreased, reaching titers <0.5UI/mL in approximately 70% of animals within the interval before the recommended booster. Thus, booster vaccination for rabies in cattle using the current vaccines should be performed before the recommended one-year interval, as to maintain neutralizing antibodies levels in most vaccinated animals.


2021 ◽  
Vol 11 (1) ◽  
pp. 64
Author(s):  
Noa Berar-Yanay ◽  
Sarit Freiman ◽  
Maʹanit Shapira ◽  
Amer Saffoury ◽  
Ameer Elemy ◽  
...  

Background and objectives: The short-term reported antibody response to SARS-COV-2 vaccination in dialysis patients is high, with a seroconversion response rate up to 97%. Data on the long-term durability of this response are scarce. Our objective was to characterize the long-term anti-spike antibody level in dialysis patients. Design, setting, participants, and measurements: In an observational study, we measured SARS-COV-2 anti-spike antibody levels in dialysis patients who completed 2 doses of the BNT162b2 mRNA SAR S-COV-2 vaccine at 1, 3 and 6 months after the second vaccine dose. We compared the response to dialysis patients who were infected with COVD-19 and to a control group of healthcare-employees. Results: One hundred and forty-two dialysis patients who had been vaccinated (ages 64 ± 11.9 years, 61% male), 33 dialysis patients who had COVID-19 infection (ages 54 ± 14.3 years, 55% male) and 104 individuals in the control group (ages 50 ± 12.2 years, 44% male) were included. The response rate in the vaccinated dialysis patients was 94%, 78% and 73% at 1, 3 and 6 months after the second vaccine dose. In the COVID-19 infected dialysis group and in the control group, the response rate remained at 100% over 6 months. The percentage of change in antibody levels between one and 6 months was −66% in the vaccinated dialysis group, −28% in the control group (p < 0.001) and +48% in dialysis patients who had been infected with COVID-19 (p < 0.001). A non-responder status at 6 months was associated with a lower albumin level. No serious adverse events following vaccination were reported. In conclusion: the initially high response rate to the BNT162b2 vaccine in dialysis patients decreases rapidly. Our results indicate that an early booster (3rd) dose, at three months after the second dose, may be advised for this population to preserve the humoral immunity.


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