High correlation between binding IgG (anti-RBD/S) and neutralizing antibodies against SARS-CoV-2 six months after vaccination

Vaccination is considered the most important measure to control the COVID-19 pandemic. Extensive fol-low-up studies with distinct vaccines and populations are able to promote robust and reliable data to better understand the effectiveness of this pharmacologic strategy. In this sense, we present data regarding binding and neutralizing antibodies throughout time, from vaccinated and previously infected (PI) health care work-ers (HCW) in Portugal. We analyzed serum samples of 132 HCW, vaccinated and with previous SARS-CoV-2 infection. Samples were collected before vaccination (baseline, M1), at second dose vaccine uptake (M2), and 25-70 days (M3) and 150-210 days (M4) after the second dose for vaccinated individuals. The IgG (anti-RBD/S) antibody geometric mean titer found on vaccinated HCW at M2 (814.7 AU/ml; 95% CI 649.8-1021.5) were sig-nificantly higher than those found on PI HCW at recruitment (M1) (252.6 AU/ml; 95% CI 108.7 - 587.1), and the neutralizing antibodies (nAb) were similar between these groups, 93.2 UI/ml (95% CI 73.2- 118.5) vs. 84.1 UI/ml (95% CI 40.4-155.9), respectively. We detected about 10-fold higher IgG (anti-RBD/S) antibodies titers in M3 when compared with M2, with a slightly but significant decrease in titers from 36 days after the second dose vaccine uptake. The increase of nAb titers were correlated with IgG (anti-RBD/S) antibodies titers, how-ever, contrasting to IgG (anti-RBD/S) antibodies titers, we did not detect a decrease in nAb titer from 36 days after a second vaccine dose uptake. At M4, was observed a decrease of 8-fold in binding IgG (anti-RBD/S) and nAb. No significant differences in antibody titers were observed by sex, age or chronic diseases. Our results suggest that IgG (anti-RBD/S) antibodies titers and nAb titers could be correlated, but ongoing follow up of the cohort, is required to better understand this correlation, and the duration of the immune response.

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Serological response to rabies virus induced by commercial vaccines in cattle

Ciência Rural ◽

10.1590/0103-8478cr20161044 ◽

2017 ◽

Vol 47 (10) ◽

Author(s):

Mathias Martins ◽

João Motta de Quadros ◽

Eduardo Furtado Flores ◽

Rudi Weiblen

Keyword(s):

Rabies Virus ◽

Neutralizing Antibodies ◽

Vaccine Dose ◽

Booster Vaccination ◽

Serological Response ◽

Serum Samples ◽

Anamnestic Response ◽

Post Vaccination ◽

Antibody Titers ◽

One Year

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.

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Antibody titers measured by commercial assays are correlated with neutralizing antibody titers calibrated by international standards

10.1101/2021.07.16.21260618 ◽

2021 ◽

Author(s):

Yu-An Kung ◽

Chung-Guei Huang ◽

Sheng-Yu Huang ◽

Kuan-Ting Liu ◽

Peng-Nien Huang ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Vaccine Development ◽

Geometric Mean ◽

Neutralizing Antibody ◽

Diagnostic Techniques ◽

International Standards ◽

World Health ◽

Serum Samples ◽

Antibody Titers ◽

Health Organization

The World Health Organization (WHO) has highlighted the importance of an international standard (IS) for SARS-CoV-2 neutralizing antibody titer detection, with the aim of calibrating different diagnostic techniques. In this study, IS was applied to calibrate neutralizing antibody titers (IU/mL) and binding antibody titers (BAU/mL) in response to SARS-CoV-2 vaccines. Serum samples were collected from participants receiving the Moderna (n = 20) and Pfizer (n = 20) vaccines at three time points: pre-vaccination, after one dose, and after two doses. We obtained geometric mean titers of 1404.16 and 928.75 IU/mL for neutralizing antibodies after two doses of the Moderna and Pfizer vaccines, respectively. These values provide an important baseline for vaccine development and the implementation of non-inferiority trials. We also compared three commercially available kits from Roche, Abbott, and MeDiPro for the detection of COVID-19 antibodies based on binding affinity to S1 and/or RBD. Our results demonstrated that antibody titers measured by commercial assays are highly correlated with neutralizing antibody titers calibrated by IS.

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Prevalence and Persistence of Maternal Dengue Neutralizing Antibodies in Infants From Central and Southern Thailand: A Retrospective Cohort Study

Asia Pacific Journal of Public Health ◽

10.1177/1010539519853396 ◽

2019 ◽

Vol 31 (4) ◽

pp. 288-295 ◽

Cited By ~ 1

Author(s):

Adrienne Guignard ◽

François Haguinet ◽

Stéphanie Wéry ◽

Phirangkul Kerdpanich

Keyword(s):

Neutralizing Antibodies ◽

Vaccine Development ◽

Geometric Mean ◽

Neutralizing Antibody ◽

Maternal Antibodies ◽

Childhood Immunization ◽

Serum Samples ◽

Denv Serotypes ◽

Antibody Titers ◽

Antibody Kinetics

Understanding maternal dengue virus (DENV) neutralizing antibody kinetics in infants remains timely to develop a safe and effective childhood immunization. This retrospective study evaluated the prevalence and persistence of maternal antibody titers against DENV serotypes 1 to 4 in 139 Thai infants at 2, 6, and 7 months of age, using serum samples collected in a vaccination trial ( http://clinicaltrials.gov ; NCT00197275). Neutralizing antibodies against all 4 DENV serotypes were detected in 87.8% and 22.9% of infants at 2 and 7 months, respectively. At 2 months, DENV-4 neutralizing antibody geometric mean titers were notably lower (80) compared with DENV-1 to DENV-3 (277-471). Our results corroborate previous findings that DENV-1 to DENV-4 maternal antibodies persist at 7 months despite titers decrease from 2 months onwards. As persisting maternal antibodies may inhibit immune responses in DENV-vaccinated infants, a comprehensive understanding of DENV antibody kinetics is required in the perspective of vaccine development for infants.

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Incidence of Infection of Enterovirus 71 and Coxsackieviruses A6 and A16 among Household Contacts of Index Cases in Dong Thap Province, Southern Vietnam

BioMed Research International ◽

10.1155/2020/9850351 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8

Author(s):

C. Q. Hoang ◽

H. D. Nguyen ◽

N. X. Ho ◽

T. H. T. Vu ◽

T. T. M. Pham ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Geometric Mean ◽

Age Groups ◽

Enterovirus 71 ◽

Foot And Mouth Disease ◽

Household Contacts ◽

Significant Difference ◽

Antibody Titers ◽

Index Cases

Background. Scarce information exists about immunity to hand, foot, and mouth disease (HFMD) among household contacts of index cases in Vietnam and what that means for reducing ongoing HFMD transmission in the community. Methods. We analyzed neutralizing antibodies (NT) and the incidence of enterovirus (EVs) infection among household contacts of index cases in a province where HFMD remains endemic. Throat swab and 2 mL blood samples from household contacts were collected at enrollment, during and after 2 weeks follow-up. Results. The incidence of EV-A71 infection among household contacts was 40/84 (47.6%, 95% Cl: 36.9-58.3%), compared with 106/336 (31.5%, 95% Cl: 26.6-36.5%) for CV-A6 and 36/107 (33.6%, 95% Cl: 24.7-42.6%) for CV-A16. The incidence of CV-A6 infection was fairly constant across ages; in contrast, CV-A71 and CV-A16 had some variation across ages. At baseline, higher geometric mean titer (GMT) of EV-A71, CV-A6, and CV-A16 antibody titers was found for 25-34-year groups (range 216.3 to 305.0) compared to the other age groups. There was a statistically significant difference in GMT values of CV-A6 and CV-A16 between those who had an infection or did not have infection among households with an index case of these serotypes. Conclusions. Our results indicated that adults were becoming infected with HFMD and could be contributing to the transmission. There is, therefore, a need for considering the household setting as an additional target for intervention programs for HFMD.

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Immunogenicity in sheep of Uruguayan commercial vaccines against bovine alphaherpesvirus 1, 5 and bovine pestiviruses

Ciência Rural ◽

10.1590/0103-8478cr20190465 ◽

2020 ◽

Vol 50 (4) ◽

Author(s):

Ingryd Merchioratto ◽

Alana de Almeida Aurélio ◽

Janice Machado Villela ◽

Nicole Vieira Stone ◽

Isac Junior Roman ◽

...

Keyword(s):

Antibody Response ◽

Neutralizing Antibodies ◽

Geometric Mean ◽

Neutralizing Antibody ◽

Serological Response ◽

Serum Samples ◽

Post Vaccination ◽

Immunological Responses ◽

Antibody Titers ◽

Low Levels

ABSTRACT: The serological responses induced by four commercial inactivated Uruguayan vaccines against bovine alphaherpesviruses (BoHV)-1 and -5 and bovine pestiviruses (BVDV-1, BVDV-2, and HoBiPeV) were evaluated in sheep. Thirty-seven sheep were immunized twice (day 0 and 25) and their serum samples were tested at different intervals (days 0, 25, 40, 60, and 90) post-vaccination (PV). Among the four vaccines tested, only one (G4) could induce the production of moderate neutralizing antibody titers against BoHV-1 and -5 and BVDV-1 and -2. The G3 vaccine showed a neutralizing serological response against the bovine alphaherpesviruses only. The G1 and G2 vaccines produced extremely low levels of antibodies in a few vaccinated animals only (geometric mean titers (GMT) 2.2). Similar levels of immunological responses were induced by the G4 vaccine against BoHV-1 and -5, and titers of neutralizing antibodies induced in approximately 70% of the animals are known to confer protection (GMT > 8). For bovine pestiviruses, the vaccine stimulated response of G4 against BVDV-2 was higher compared to that against BVDV-1, and extremely low for HoBiPeV. The peak of neutralizing antibodies to BoHV-1 and BVDV-1 was observed on days 40 and 60 PV, respectively. Thereafter, a remarkably decrease in neutralizing antibody response was observed at day 90 PV. These results demonstrated that tested commercial Uruguayan vaccines did not induce a serological response of adequate magnitude and duration. Thus, it is important to periodically review formulations and compositions of commercial vaccines against bovine alphaherpesviruses and pestiviruses.

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Neutralizing Antibody Response to Pseudotype SARS-CoV-2 Differs between mRNA-1273 and BNT162b2 COVID-19 Vaccines and by History of SARS-CoV-2 Infection

10.1101/2021.10.20.21265171 ◽

2021 ◽

Author(s):

Harmony L. Tyner ◽

Mark G. Thompson ◽

Jefferey L. Burgess ◽

Lauren Grant ◽

Manjusha Gaglani ◽

...

Keyword(s):

Antibody Response ◽

Messenger Rna ◽

Neutralizing Antibodies ◽

Geometric Mean ◽

Vaccine Dose ◽

Neutralizing Antibody ◽

Frontline Workers ◽

History Of ◽

Antibody Titers ◽

Polymerase Chain

Background: Data on the development of neutralizing antibodies against SARS-CoV-2 after SARS-CoV-2 infection and after vaccination with messenger RNA (mRNA) COVID-19 vaccines are limited. Methods: From a prospective cohort of 3,975 adult essential and frontline workers tested weekly from August, 2020 to March, 2021 for SARS-CoV-2 infection by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) assay irrespective of symptoms, 497 participants had sera drawn after infection (170), vaccination (327), and after both infection and vaccination (50 from the infection population). Serum was collected after infection and each vaccine dose. Serum-neutralizing antibody titers against USA-WA1/2020-spike pseudotype virus were determined by the 50% inhibitory dilution. Geometric mean titers (GMTs) and corresponding fold increases were calculated using t-tests and linear mixed effects models. Results: Among 170 unvaccinated participants with SARS-CoV-2 infection, 158 (93%) developed neutralizing antibodies (nAb) with a GMT of 1,003 (95% CI=766-1,315). Among 139 previously uninfected participants, 138 (99%) developed nAb after mRNA vaccine dose-2 with a GMT of 3,257 (95% CI = 2,596-4,052). GMT was higher among those receiving mRNA-1273 vaccine (GMT =4,698, 95%CI= 3,186-6,926) compared to BNT162b2 vaccine (GMT=2,309, 95%CI=1,825-2,919). Among 32 participants with prior SARS-CoV-2 infection, GMT was 21,655 (95%CI=14,766-31,756) after mRNA vaccine dose-1, without further increase after dose-2. Conclusions: A single dose of mRNA vaccine after SARS-CoV-2 infection resulted in the highest observed nAb response. Two doses of mRNA vaccine in previously uninfected participants resulted in higher nAb to SARS-CoV-2 than after one dose of vaccine or SARS-CoV-2 infection alone. Neutralizing antibody response also differed by mRNA vaccine product.

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Comparative immune responses of pups following modified live virus vaccinations against canine parvovirus

Veterinary World ◽

10.14202/vetworld.2019.1422-1427 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1422-1427

Author(s):

Jayalakshmi Vasu ◽

Mouttou Vivek Srinivas ◽

Prabhakar Xavier Antony ◽

Jacob Thanislass ◽

Vijayalakshmi Padmanaban ◽

...

Keyword(s):

Immune Responses ◽

Antibody Titer ◽

Neutralizing Antibodies ◽

Geometric Mean ◽

Booster Vaccination ◽

Primary Vaccination ◽

Canine Parvovirus ◽

Serum Samples ◽

Live Virus ◽

Antibody Titers

Background and Aim: Canine parvovirus (CPV) is the most important viral cause of enteritis and mortality in pups. Evaluation and monitoring of pre- and post-vaccine immune responses may help to determine the efficacy of the current vaccination schedule being followed in pups in India. This study aimed to evaluate and monitor the pre- and post-vaccine immune responses of CPV vaccinated pups using hemagglutination inhibition (HI) assay. The neutralizing antibody titer levels were also detected using serum neutralization test (SNT). Materials and Methods: The pups were categorized into two groups, the double booster and the single booster groups. In this study, serum samples were subjected to HI and SNT for measuring the CPV antibody titer at frequent intervals for up to 6 months from 27 healthy pups following primary and booster CPV vaccinations. Results: The antibody titers in double booster pups reached their peaks at the 21st day after the second booster vaccination with a geometric mean (GM) of 3.57. The antibody titers in single booster pups reached their peaks at the 21st day after the first booster vaccination with a lower GM of 3.18. Conclusion: The double booster pups maintained a higher immune response throughout the period of the study compared to single booster pups though the difference in titers was not statistically significant. SNT results indicated that the raised antibody titer was also able to yield virus-neutralizing antibodies. No interfering maternally derived antibodies were found in the pups at the age of primary vaccination (45th day) in our study. Therefore, the second booster vaccination may be useful in maintaining the protective titer for a prolonged period.

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Durability of Response to a Third BNT162b2 Vaccine in Adults ≥60 Years

10.1101/2021.12.25.21268336 ◽

2021 ◽

Author(s):

Noa Eliakim Raz ◽

Amos Stemmer ◽

Yaara Leibovici-Weissman ◽

Asaf Ness ◽

Muhammad Awwad ◽

...

Keyword(s):

Adverse Events ◽

Neutralizing Antibodies ◽

Multivariable Analysis ◽

Vaccine Dose ◽

Neutralizing Antibody ◽

Clinical Frailty Scale ◽

Younger Adults ◽

The Third ◽

Antibody Titers ◽

Level 2

BACKGROUND Age and frailty are strong predictors of COVID-19 mortality. After the second BNT162b2 dose, immunity wanes faster in older (≥65 years) versus younger adults. The durability of response after the third vaccine is unclear. METHODS This prospective cohort study included healthcare workers/family members ≥60 years who received a third BNT162b2 dose. Blood samples were drawn immediately before (T0), 10-19 (T1), and 74-103 (T2) days after the third dose. Antispike IgG titers were determined using a commercial assay, seropositivity was defined as ≥50 AU/mL. Neutralizing antibody titers were determined at T2. Adverse events, COVID-19 infections, and clinical frailty scale (CFS) levels were documented. RESULTS The analysis included 97 participants (median age, 70 years [IQR, 66-74], 61% women, 58% CFS level 2). IgG titers, which increased significantly from T0 to T1 (medians, 440 AU/mL [IQR, 294-923] and 25,429 [14,203-36,114] AU/mL, respectively; P<0.001), decreased significantly by T2, but all remained seropositive (median, 8,306 AU/mL [IQR, 4595-14,701], P<0.001 vs T1). In a multivariable analysis, only time from the first vaccine was significantly associated with lower IgG levels at T2 (P=0.004). At T2, 60 patients were evaluated for neutralizing antibodies; all were seropositive (median, 1,294 antibody titer [IQR, 848-2,072]). Neutralizing antibody and antispike IgG levels were correlated (R=0.6, P<0.001). No major adverse events or COVID-19 infections were reported. CONCLUSIONS Antispike IgG and neutralizing antibodies levels remain adequate 3 months after the third BNT162b2 vaccine in healthy adults ≥60 years, although the decline in IgG is concerning. A third vaccine dose in this population should be top priority.

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Can we predict antibody responses in SARS-CoV-2? A cohort analysis

10.1101/2021.03.15.21253267 ◽

2021 ◽

Author(s):

Mary Gaeddert ◽

Philip Kitchen ◽

Tobias Broger ◽

Stefan Weber ◽

Ralf Bartenschlager ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Severe Disease ◽

Cohort Analysis ◽

Antibody Responses ◽

High Antibody ◽

Igg Antibodies ◽

Rt Pcr ◽

Median Increase ◽

Antibody Titers

AbstractBackgroundAfter infection with severe acute respiratory syndrome coronavirus (SARS-CoV-2), Immunoglobulin G (IgG) antibodies and virus-specific neutralizing antibodies (nAbs) develop. This study describes antibody responses in a cohort of recovered COVID-19 patients to identify predictors.MethodsWe recruited patients with confirmed SARS-CoV-2 infection from Heidelberg, Germany. Blood samples were collected three weeks after COVID-19 symptoms ended. Participants with high antibody titers were invited for follow-up visits. IgG titers were measured by the Euroimmun Assay, and nAbs titers in a SARS-CoV-2 infection-based assay.Results281 participants were enrolled between April and August 2020 with IgG testing, 145 (51.6%) had nAbs, and 35 (12.5%) had follow-up. The median IgG optical density (OD) ratio was 3.1 (Interquartile range (IQR) 1.6-5.1), and 24.1% (35/145) had a nAb titer>1:80. Higher IgG titers were associated with increased age and more severe disease, and higher nAbs were associated with male gender and CT-value of 25-30 on RT-PCR at diagnosis. The median IgG OD ratio on follow-up was 3.7 (IQR 2.9-5.9), a median increase of 0.5 (IQR −0.3-1.7). Six participants with follow-up nAbs all had titers ≤ 1:80.ConclusionsWhile age and disease severity were correlated with IgG responses, predictive factors for nAbs in convalescent patients remain unclear.

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Seroprevalence of measles antibodies and factors associated with susceptibility: a national survey in Mexico using a plaque reduction neutralization test

Scientific Reports ◽

10.1038/s41598-020-73618-8 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

José Luis Díaz-Ortega ◽

Elizabeth Ferreira-Guerrero ◽

Luis Pablo Cruz-Hervert ◽

Guadalupe Delgado-Sánchez ◽

Leticia Ferreyra-Reyes ◽

...

Keyword(s):

National Survey ◽

Vaccine Dose ◽

Effective Vaccine ◽

Sample Population ◽

Serum Samples ◽

Nutrition Survey ◽

Factors Associated ◽

Measles Antibodies ◽

Antibody Titers ◽

Increased Susceptibility

Abstract Measles continues to be one of the leading causes of child mortality worldwide, even though a highly effective vaccine has existed for more than 40 years. We aimed to describe the seroprevalence of measles antibodies in Mexico in 2012 and the risk factors associated with susceptibility. A total of 7,785 serum samples were analyzed from the National Health and Nutrition Survey in Mexico. This national survey is representative of the general population, including noninstitutionalized adult, adolescent, and child populations. Antibody titers were classified into protective (> 120 mIU/mL) or susceptible (≤ 120 mIU/mL) levels. The weighted seroprevalence and susceptibility of the overall population were 99.37% (95% CI 99.07–99.58) and 0.63% (95% CI 0.42–0.93), respectively. Among 1-to-4-year-old children, 2.18% (95% CI 1.36–3.48) were susceptible to measles. Among adolescents and young adults, the prevalence of susceptibility was as follows: those 15–19 years of age had a prevalence of 0.22% (95% CI 0.09–0.57), and those 30–39 years of age had a prevalence of 1.17% (95% CI 0.47–2.85). Susceptibility was associated with young age, living in Mexico City, living in crowded households and unknown or nonvaccinated status among 1- to 5-year-old children. Although the overall sample population seroprevalence for measles is above 95%, increased susceptibility among younger children signals the importance of the timely administration of the first vaccine dose at 12 months of age. Furthermore, increased susceptibility among specific subgroups indicates the need to reinforce current vaccination policies, including the immunization of unvaccinated or incompletely vaccinated individuals from 10 to 39 years of age.

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