Post-vaccination Immune Response Research Articles

Robust Vaccine-Induced as Well as Hybrid B- and T-Cell Immunity across SARS-CoV-2 Vaccine Platforms in People with HIV.

Few studies have comprehensively compared severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine-induced and hybrid B- and T-cell responses in people with HIV (PWH) to those in comparable controls without HIV. We included 195 PWH and 246 comparable controls from the AGEhIV COVID-19 substudy. A positive nucleocapsid antibody (INgezim IgA/IgM/IgG) or self-reported PCR test defined prior SARS-CoV-2 infection. SARS-CoV-2 anti-spike (anti-S) IgG titers and anti-S IgG production by memory B cells were assessed. Neutralizing antibody titers were determined in a subset of participants. T-cell responses were assessed by gamma interferon (IFN-γ) release and activation-induced marker assay. We estimated mean differences in postvaccination immune responses (β) between levels of determinants. Anti-S IgG titers and anti-S IgG production by memory B cells were not different between PWH and controls. Prior SARS-CoV-2 infection (β = 0.77), receiving mRNA vaccine (β = 0.56), female sex (β = 0.24), fewer days between last vaccination and sampling (β = 0.07), and a CD4/CD8 ratio of <1.0 (β = -0.39) were independently associated with anti-S IgG titers, but HIV status was not. Neutralization titers against the ancestral and Delta and Omicron SARS-CoV-2 variants were not different between PWH and controls. IFN-γ release was higher in PWH. Prior SARS-CoV-2 infection (β = 2.39), HIV-positive status (β = 1.61), and fewer days between last vaccination and sampling (β = 0.23) were independently associated with higher IFN-γ release. The percentages of SARS-CoV-2-reactive CD4+ and CD8+ T cells, however, were not different between PWH and controls. Individuals with well-controlled HIV generally mount robust vaccine-induced as well as hybrid B- and T-cell immunity across SARS-CoV-2 vaccine platforms similar to controls. Determinants of a reduced vaccine response were likewise largely similar in both groups and included a lower CD4/CD8 ratio. IMPORTANCE Some studies have suggested that people with HIV may respond less well to vaccines against SARS-CoV-2. We comprehensively compared B- and T-cell responses to different COVID-19 vaccines in middle-aged persons with well-treated HIV and individuals of the same age without HIV, who were also highly comparable in terms of demographics and lifestyle, including those with prior SARS-CoV-2 infection. Individuals with HIV generally mounted equally robust immunity to the different vaccines. Even stronger immunity was observed in both groups after prior SARS-CoV-2 infection. These findings are reassuring with respect to the efficacy of SARS-Cov-2 vaccines for the sizable and increasing global population of people with HIV with access and a good response to HIV treatment.

INVESTIGATING THE SEROLOGICAL RESPONSE AND SAFETY OF BRUCELLA MELITENSIS REV.1 CONJUNCTIVAL VACCINE IN SMALL RUMINANTS

Mass vaccination, which is one of the main control policies, provides herd immunity against infectious diseases. This could contribute to the control of the disease and eventually its eradication. The purpose of this study was to investigate the safety and humoral immune response of Brucella melitensis Rev.1 vaccine before the start of mass vaccination. A total of 741 sheep and goats were vaccinated conjunctivally. No adverse effect was observed after the vaccination of the animals. No abortion was seen in pregnant animals. Vaccine strain was isolated from some milk samples taken from only lactating vaccinated goats. Excretion of the vaccine strain was not intense and long-termed. Post-vaccination immune response was evaluated by serological tests, namely, Rose Bengal Plate Test, Serum Agglutination Test and Complement Fixation Test. One month after vaccination, the immune response was high, and the decrease of antibody titers was the highest four to six months after vaccination by inversely correlated with the age of the vaccinated animals. In conclusion, we observed that Brucella melitensis Rev.1 vaccine, used conjunctivally, was safe enough for the animals, and vaccinated animals had high vaccine-induced immune response.

Study of Humoral Immunity against Coronavirus Infection COVID-19 in Vaccinated Individuals with Vaccines Available in the Republic of Belarus (Sputnik V (Gam-COVID-Vac), RF and Sinopharm (BBIBP-CorV), PRC)

Relevance. Many countries around the world are developing effective vaccines against SARS-CoV-2. The measure of the effectiveness of the vaccination process has traditionally been antibody production. The frequency and intensity of adverse reactions is also an important factor in making a decision regarding a vaccine. This study presents the results of the evaluation of the formation of humoral immunity and the occurrence of reactions in response to the administration of Sputnik V (Gam-COVID-Vac), RF, and Sinopharm (BBIBP-CorV), PRC. Aim. Analyze immunogenicity and reactogenicity of COVID-19 vaccines used in the Republic of Belarus (Sputnik V and Sinopharm). Materials and methods. Evaluation of postvaccination immune response by enzyme immunoassay and differential enzyme immunoassay for class G immunoglobulins to S- and N-proteins SARS-CoV-2. Blood plasma of the study participants was used as biological material. Blood sampling was performed 3 times: immediately before the first vaccine dose, on day 42, and 6 months after the first vaccine dose. To evaluate the frequency and intensity of postvaccination reactions, study participants were questioned. Results. At 42 days after administration of both vaccines, antibody levels are rising, with a significantly higher quantitative IgG count for the Sputnik V vaccine. This trend is also observed 6 months after the first dose of both vaccines, both among those previously infected with SARS-CoV-2 and those without a history of COVID-19. The comparison of Sputnik V and Sinopharm vaccine groups in terms of IgG (BAU/ml) levels to S- and N-proteins revealed a statistically significant difference in IgG levels to S-protein: the Sputnik V vaccine group had significantly higher IgG levels to S-protein than the Sinopharm vaccine group (p = 0.0000196). The incidence of adverse reactions in this study was 45%. All reactions noted were mild to moderate in severity. The most common were soreness and redness at the injection site, elevated body temperature, and a combination of several reactions. The increased body temperature after vaccination was more common among those vaccinated with the Sputnik V vaccine. Conclusion. Compared to Sinopharm, Sputnik V vaccine produces higher antibody level. Adverse reactions were observed in both vaccinated groups. However, significant statistical differences were found with regard to fever in the Sputnik V vaccine group, which occurred more frequently.

About Immunological Studies in “Sirius” University

This short report summarizes the results of recent immunological studies conducted at the new Sirius University of Science and Technology. The main area of work is dedicated to the study of the features of the post-vaccination immune response against SARS-CoV-2, as well as the search for potential agents to block that infection.

Waning immune response to CoronaVac in health care workers from different age groups.

The waning of serum antibodies against severe acute respiratory syndrome coronavirus 2 observed in several studies raises questions about long-term immunity. Lower antibody levels are associated with new cases of COVID-19 even postvaccination, leading to the administration of booster doses. To evaluate the postvaccination immune humoral response and the relationship between postvaccination seropositivity rates and demographic data among health care workers 6 months after CoronaVac vaccination. This was a cross-sectional study including health care workers vaccinated with two doses of CoronaVac after 6 months or more. The present study was conducted with the analysis of postvaccination serology test to assess the level of humoral response (anti-receptor binding domain IgG) after vaccination. A total of 325 participants were enrolled, of whom 76% were female, with a median age of 42 years (20-85; interquartile range 31-53). Overall, 18.8% (61) of the participants results were seropositive for anti-receptor binding domain IgG; 81.2% did not have sufficient quantitative titers. The IgG titers obtained from female health care workers did not differ from those obtained from seropositive male health care workers, regardless of age. A group of positive quantitative titers was identified in the serology test for IgG antibodies against severe acute respiratory syndrome coronavirus 2. Further studies are needed to determine the durability of postvaccination antibodies and how serology testing can be used to determine the ideal timing for booster doses of the vaccine.

Assessment of Post-Vaccination Immunologic Responses in Inactivated Virus COVID-19 Respondents.

The Indonesian Government's plan to contain the COVID-19 pandemic, aside from implementing health protocols, also involves vaccinating everyone with the inactivated SARS CoV2 vaccine until herd immunity is reached. The aim of this study was to assess the post-vaccination immune response to inactivated SARS CoV2 vaccine, namely Sinovac/Sinopharm, by measuring the antibodies (IgM and IgG) in subjects after their second dose of vaccination. The design of the study was a cohort study using simple random sampling with 51 respondents aged 18-56 years who had received two doses of inactivated SARS-CoV-2 vaccine. All respondents were screened for SARS-CoV-2 infection prior to inclusion. Serum IgM and IgG antibodies were detected using a specific and sensitive automated chemiluminescent immunoassay (CLIA). CLIA uses the Cut Off Point (COI) value of >1 AU/ml for IgM and the Reactive Value of >10 AU/ml for IgG. This study showed that the IgM levels using a reactive Cut Off Point (COI) >1 were 18% in the first month, 14% in the third month, and 10% in the sixth month. There was a constant decline in the third comparison. Meanwhile, compared to the first month, 59% of respondents had IgG levels with reactive values over 10 AU/ml, which after decreasing by 35% in the third month, the number increased by 47% in the sixth month. It has been evident that IgG and IgM antibody response could be induced by inactivated SARS-CoV-2 vaccine which can be influenced by age and detection time after the second dose of vaccination. Boosters, however, must be given after six months of the second dose, since antibody levels were seen to decrease after this period.

COVID-19 vaccination in patients with multiple sclerosis receiving disease-modifying therapies: pragmatic issues.

The SARS-COV-2 pandemic has been a global public health problem since 2019, with over 400 million reported cases, 6 million deaths, and significant economic and social damage. Overlapping SARS-CoV-2 infection in patients with chronic diseases, such as multiple sclerosis (MS), causes management problems, especially in patients treated with disease-modifying therapies. Studies investigating COVID-19 vaccination effectiveness have shown variability in postvaccination immune response that depends on the patient's background treatment, and special attention is required for anti-CD20 therapies. Existing data on the efficacy of COVID-19 vaccination in patients with MS undergoing disease-modifying treatment are summarized and critically evaluated in this article.

Features of post-vaccination humoral immune response in the persons who underwent COVID-19 of various severity

The studies on humoral immune response in the individuals who have undergone COVID-19 and vaccinated with anti-COVID vaccines allows us to assess the development of “hybrid” immunity, which contributes to understanding the mechanisms of its formation from the effector phase to the step of immunological memory. We assessed the relative and absolute contents of B cell populations and subpopulations, development of humoral immunity in the patients who suffered with COVID-19 of varying severity being thereafter vaccinated with “KoviVak” and “Sputnik V”. The study involved volunteers (age 47.3±14.5 years) who beared COVID-19 asymptomatically (n = 32), at moderate severity (n = 21), or had severe form of the disease (n = 12), then being vaccinated with “KoviVak” and “Sputnik V” 6-9 months after their recovery. The groups of vaccinated persons consisted of those who beared severe disease being vaccinated with “KoviVak” (n = 6) or “Sputnik V” (n = 6); moderate cases, vaccinated with “KoviVak” (n = 10) and “Sputnik V” (n = 11); asymptomatic cases vaccinated with “KoviVak” (n = 10) and “Sputnik V” (n = 22). We have determined relative and absolute numbers of B lymphocytes (CD45+CD19+), B1 lymphocytes (CD45+CD5+CD19-CD27-), B2 lymphocytes (CD45+CD19+CD5-CD27-), total population of memory B cells (CD45+CD19+CD5-CD27+), non-switched (CD45+CD19+IgD+CD27+), and switched (CD45+CD19+IgD-CD27+) memory B cells; mature naive B lymphocytes (CD45+CD19+CD27-IgD+), plasmoblasts (CD45+CD19+CD38+++IgD-CD27+), as well as presence of IgG to S(RBD)-SARS-CoV-2 protein.We have found that the humoral immunity among survivors of COVID-19 of varying severity is expressed for up to nine months. The largest number of volunteers who raised antibodies to SARS-CoV-2 S-protein was registered in the group of seriously ill patients. As soon as 1 month after “Sputnik V” vaccination and until the end of the observation, all the examined subjects in this group became seropositive. 4-5 months after injection of this vaccine, specific immunoglobulins were present in all patients who had asymptomatic or average-severity infection. All volunteers who received “KoviVak” had antibodies to the COVID-19 viral S protein from the beginning to the end of the study. Vaccination, especially with “KoviVak”, contributed to the highest increase, both in relative and absolute numbers of memory B lymphocytes in asymptomatic patients. Less pronounced changes in the content of B lymphocytes in COVID-19 patients who had severe and moderate clinical course may be associated with higher levels of these cells prior to injection of the vaccines. A positive correlation was found between the number of memory B cells and presence of immunoglobulins to the S protein SARS-CoV-2 in all examined patients.

Assessment of post-vaccination immune response to peste des petits ruminants virus in small ruminants in the central and western regions of India.

The online version contains supplementary material available at 10.1007/s13337-022-00796-6.

Evaluation of the analytical performance of three chemiluminescence serological assays for detecting anti-SARS-CoV-2 antibodies.

The serology surveillance of SARS-CoV-2 antibodies represents a useful tool for monitoring protective immunity in the population. We compared the performance of three SARS-CoV-2 antibody serological immunoassays in 600 vaccinated subjects after the BNT162b2 mRNA COVID-19 vaccine. All serum samples were evaluated by three different immunoassays for detecting anti-SARS-COV-2 antibodies. All SARS-CoV-2 antibody serological immunoassays could detect, when present, a post-vaccine humoral immune response. Median (interquartile range, IQR) anti-S-RBD IgG, Access SARS-CoV-2 IgG (1st IS) and Access SARS-CoV-2 IgG II levels of the subjects investigated were, respectively, 687 BAU/mL (131–2325), 419 IU/mL (58–1091) and 104 AU/mL (14–274). By studying a cohort of unvaccinated subjects, without previous COVID-19 infection, we found a high specificity for all methods. A high correlation was found between IgG titres. Considering the kinetics of subjects with multiple doses, we observed that percentage decreasing gradients were comparable across methods. Our results suggest that all the SARS-CoV-2 antibody serological immunoassays evaluated in this study are suitable for monitoring IgG titers over time. This study contributes to a better understanding of antibody response in vaccinated subjects using some currently available assays.

Evaluation of specific T cell immune response to SARS-CoV-2 in COVID-19 infection and following Gam-COVID-Vac vaccine prophylaxis

An aberrant immune response during SARS-CoV-2 infection has been shown to determine the clinical features, disease severity, and progression of COVID-19 infection. This work aimed for comprehensive assessment of the immune response by comparative evaluation of diagnostic significance of the antibodies to RBD domain of the SARS-CoV-2 spike protein, as well as detection of effector CD4+ and CD8+T cells specific to SARS-CoV-2 antigens. The study was performed in unvaccinated persons, healthy individuals vaccinated with Gam-COVID-Vac, and in the patients who have had COVID-19 infection. We have found that IgG antibodies to the RBD domain of the SARS-CoV-2 spike protein are detectable at a frequency of 73% to 92% of cases in vaccinated persons and COVID-19 reconvalescents. The numbers of effector CD4+ and CD8+T lymphocytes responding to stimulation with SARS-CoV-2 antigens by producing the IFN cytokine varied depending on the introduced antigen and tended to be higher in vaccinated individuals. In non-vaccinated healthy persons who contacted with COVID-19 patients, T cell response to the SARS-CoV-2 nucleoproteins was revealed. For adequate assessment of antiviral and post-vaccination immune response to COVID-19, it would be necessary to study not only humoral immune response by the presence of antibodies, but also functionally active specific T lymphocytes directed for SARS-CoV-2 protein antigens.

P-656 Effect of COVID-19 vaccination on clinical outcome in fully vaccinated infertile women undergoing IVF/ICSI cycles at tertiary care centre: prospective observational study

Study questionDoes immune response to COVID-19 vaccination affect the clinical outcome in fully vaccinated infertile women undergoing IVF/ICSI cycles?Summary answerCOVID-19 IgG antibodies are present in follicular fluid post vaccination and higher immune response increases duration of gonadotrophins required and negatively impacts the IVF outcome.What is known alreadyRecent studies assessed the influence of COVID-19 infection and mRNA COVID-19 vaccine on the stimulation cycle characteristics and embryological variables of patients undergoing IVF cycle and found no effect on the IVF outcome in their immediate IVF cycle after recovery, except for a decreased number of top quality embryos. One study reported infection or mRNA vaccine results in rapid formation of anti-COVID IgG which can be detected in follicular fluid. This immune response did not lead to any significant negative effect on ovarian follicular function. There is a possibility that COVID-19 infection might affect numerous fertility-linked proteins.Study design, size, durationProspective observational study, conducted at Division of Reproductive Medicine of tertiary care institute. After taking informed consent, 32 patients who satisfy the inclusion and exclusion criteria with history of receiving two doses of Covishield or Covaxin vaccine with at-least 2 weeks from last dose, were recruited for IVF/ICSI cycles from December 2021 to January 2022, for assessing COVID-19 IgG antibodies in their follicular fluid.Participants/materials, setting, methodsWomen of 21-40 years with normal ovarian reserve and normal uterine cavity were included, those with history of COVID infection were excluded. All patients underwent GnRH antagonist protocol. Follicular fluid was collected at time of oocyte retrieval. After collecting oocytes, 400 microlitre of follicular fluid was stored at -80 and later thawed and analysed for SARS-CoV-2 IgG antibodies (ADVIA Centaur COV2G assay, Germany) which are expressed in index value and reported as reactive (≥1 index).Main results and the role of chanceOut of 32, 21 (65.6%) of the participants had received COVISHIELD (V1)and 11 (34.3%) received COVAXIN (V2). The mean gap between vaccine and the IVF cycle was 84.94 ± 52.65 days. The mean COVID IgG antibody titres (Index) were significantly higher in V1, 28.77±33.50 (0.34 -100), than V2 2.28±3.74(0.05-13.23), p<0.001. Patients with higher antibody titres, required longer duration of ovarian stimulation, rho=0.42, p = 0.017. Patients with higher COVID IgG antibodies were negatively correlated with clinical pregnancy rate (20.9 0± 29.68 vs 4.60 ± 6.28, p = 0.153). The time gap from the last dose of vaccine to IVF cycle had moderate negative correlation with percentage of grade-I embryos out of the total embryos fertilised (%), rho= -0.33, p = 0.068. Furthermore, higher gonadotropins doses were required in patients with high antibody titres, rho=0.25, p = 0.160, and amongst V1 vs V2, total dose of gonadotropins required was 3802.38±742.92 vs 3422.73±564.52, respectively, p=0.115. COVID IgG antibody titres had weak negative correlation with number of grade-I embryos, rho= -0.16, p = 0.396. The time gap from the last dose of vaccine to IVF cycle had a weak negative correlation with number of grade-I embryos, rho=-0.28, p = 0.124.Limitations, reasons for cautionThe main limitation of this study is small sample size. However, the study is currently ongoing, and these are the interim results of the same. As prospective studies with larger sample size would be required to assess the effect of different COVID-19 vaccines in different populations on the IVF outcomes.Wider implications of the findingsThe present study confirms the presence of COVID IgG antibodies in follicular fluid in vaccinated women, and proves that COVISHIELD vaccinated patients had higher antibody titres. Higher antibody titres require longer duration of stimulation and result in poorer outcomes so a longer interval from vaccine to IVF should be recommended.Trial registration numberNA

The innate immune response following multivalent dengue vaccination and implications for protection against dengue challenge.

Understanding the immune response to dengue virus (DENV) is essential for developing a dengue vaccine that is protective against all 4 DENV serotypes. We evaluated the immune response after vaccination (live attenuated tetravalent dengue vaccine TV005 or trivalent admixture) and after challenge with DEN2Δ30 (Tonga/74) to better understand the importance of homotypic immunity in vaccine protection. Significant increases in IP-10 expression were observed following receipt of either the trivalent or tetravalent vaccine. After challenge, a large increase in IP-10 expression was observed in the placebo and trivalent admixture groups but not in the tetravalent vaccine group. MCP-1, IL-1RA, and MIP-1β exhibited a similar pattern as IP-10. These results demonstrate protective effects of trivalent and tetravalent vaccines against DENV and suggest that the tetravalent vaccine has a better protective effect compared with the trivalent admixture. We also explored the postvaccination and postchallenge immune response differences between Black and White participants. White participants responded to vaccine differently than Black participants; Black participants receiving trivalent and tetravalent vaccines responded strongly and White participants responded only transiently in trivalent group. In response to challenge, White participants elicited a stronger response than Black participants. These results may explain why White participants may have a more vigorous DENV immune response than Black participants, as reported in literature.

Evaluation of the epidemiological significance of molecular genetic factors in relation to the intensity of post-vaccination immunity against hepatitis B

Introduction. Hepatitis B retains the status of socially significant infection and remains a major health problem worldwide, including the Russian Federation. The improvement of the effectiveness of the current complex of preventive measures, especially vaccination, is an important task for public health. Although vaccination against hepatitis B is highly successful, 5% to 10% of individuals do not experience a response to vaccine with an adequate level of antibodies to hepatitis B surface antigen (anti-HBs). One of the key factors determining the absence or insufficiency of post-vaccination immunity against hepatitis B may be the single-nucleotide polymorphisms (SNPs) that change gene sequences, including those that determine the mechanism of immunogenesis. Such genetic changes may affect the signaling pathways and result in significant decrease in antibody response to hepatitis B vaccine. Assessment of epidemiological significance of such SNPs is an important task, considering its possible associations with failure to respond adequately to vaccination.The aim of the study was to determine the effect of SNPs of IL1B (rs1143634, rs1143627), IL1RN (rs4251961, rs419598), IL6 (rs1800795), IL10 (rs1800896), TULP1 (rs9380516), TLR4 (rs4986790), MERTK (rs4374383) genes on the formation of post-vaccination immunity against hepatitis B.Materials and methods. Healthcare workers (n = 271) of the Treatment and Rehabilitation Center of the Ministry of Health of the Russian Federation with known vaccination history, data on age, work experience and department of the medical institution were included in this research. The presence and levels of anti-HBs and anti-HBcore IgG antibodies were determined by the ELISA method using the DS-ELISA-ANTI-HBs and DS-ELISA-ANTI-HBc kits, according to the manufacturer’s instructions. Genotyping was performed by real time polymerase chain reaction. Statistical analysis of data was carried out using the "Statistica 6.0" software.Results. Statistically significant differences in the frequencies of CC (rs9380516) genotypes (p = 0.034; OR 0.497; 95% CI 0.261–0.949) and CT (p = 0.044; OR 1.967; 95% CI 1.015–3.812) of the TULP1 gene in the group of individuals with anti-HBs concentrations of 10–100 IU/l were found in association with the intensity of the post-vaccination response against hepatitis B. Also, for this group, differences were found in the structure of the TT/CT genotype pair of IL-10/TULP1 genes (rs1800896/rs9380516) (p = 0.003; OR = 5.39; 95% CI 1.7–17.4) and for the combination of AA/TT SNP MERTK/IL1RN genotypes (rs4374383/rs4251961) (p = 0.003; OR = 7.96; 95% CI 1.7–37.6).Conclusion. Our study revealed that above variants of genotypes could play a role in predicting an increased risk of low (or absence) post-vaccination immune response against hepatitis B. It seems appropriate to use the relationship between the gene polymorphisms and a low concentration of post-vaccination anti-HBs antibodies in assessing scenarios for the development of the epidemic process of hepatitis B, since the identified associations allow to quantify the risks of poor herd immunity against this infection.

MO1016: Features of the Formation of Post-Infectious and Post-Vaccinal Humoral Immune Response to SARS-COV-2 in Kidney Recipients

BACKGROUNDThis paper presents the results of studying the characteristics of the antibody response in kidney recipients who are at high risk of severe COVID-19.METHODThe study of features of the formation of post-infectious anti-SARS-CoV-2 IgG was carried out in the group of kidney recipients (n = 171) with PCR confirmed diagnosis of COVID-19. Studies of the characteristics of post-vaccination immunity were carried out in a group of vaccinated recipients (n = 49) with Sputnik V (Russia) or Vero Cell (China).ELISA was used to detect IgG to S and N proteins of the SARS-CoV-2.Comparative studies used a simple randomized selection of immunocompetent COVID-19 patients (n = 163).Statistical data processing was carried out using the χ2 and Wald's methods.RESULTSIt was found that 30 days after the onset of clinical symptoms of COVID-19 in kidney recipients, IgG to S and/or N proteins of SARS-CoV-2 were detected in 89.5% (83.9%–93.3%) of them. The detection rate of IgG to the S protein was higher than that to the N protein [87.7% (81.9%–91.9%) and 62.0% (54.5%–68.9%), respectively). At the same time, the seroprevalence to the pathogen varied by age: in the 18–34-year-old group it was 77.7% (59.9%–88.9%), in the 50–64-year-old group it was 96.7% (88.2%–99.8%) and in the group >64 years old it was 80.0% (66.8%–89.0%). This trend of antibody production in older recipients correlated with the highest frequency of registration in them of moderate and severe forms [66.7% (56.4%–75.6%)]. Differences due to the severity of the disease were noted both in the frequency of detectable antibodies [80.3% (69.5%–88.0%) in recipients with a mild form of COVID-19 and 96.0% in recipients with a severe form of infection (P < .001)] and in the intensity of the formed anti-SARS-CoV-2 immunity. Thus, high values of PC (positivity coefficient) (>12) to S protein were recorded in 52.7% (39.8%–65.3%) and 63.2% (53.1%–72.2%) patients with mild and severe forms of COVID-19, respectively, which indicated a direct dependence of the production of antiviral antibodies on the severity of the infection. It was found that in 62.6% (55.1%–69.5%) of recovered recipients anti-SARS-CoV-2 IgG persisted for a period of 3 months from the onset of infection. In a significant proportion of recipients [42.8% (35.5%–50.2%)], antibodies were detected for up to 15 months. In general, the post-infectious antibody response in kidney recipients and immunocompetent patients had similar patterns of development. Despite the general mechanism of antibody production, in immunocompetent patients, the frequency of detection of antiviral antibodies (to N protein: 82.9% and to S protein: 91.2%), tension indicators (high values of PC to N protein: 51.0% and to S protein: 75.5%) and the duration of retention (in 50.3% at 15 months of monitoring) were slightly higher than the same parameters in recipients with COVID-19.In kidney recipients after immunization with Sputnik V and Vero Cell (n = 34), a rather low detection rate of antiviral IgG [52.9% (36.7%–68.6%) compared with a similar parameter (P < .001) in vaccinated immunocompetent individuals [96.8% (94.8%–98.1%)] was found. The seroprevalence in the group of recipients with hybrid immunity (after illness and vaccination, n = 15) was 86.7% (60.9%–97.5%). In a comparative analysis of the intensity of post-vaccination immunity, high values of PC to S protein (>12) were recorded in 44.0% (26.7%–62.9%) of recipients vaccinated with Sputnik V and 50.0% (31.4%–68.6%) of recipients vaccinated with Vero Cell. The inverse relationship was observed in immunocompetent individuals: 64.7% (58.1%–70.7%) for Sputnik V and 44.2% (36.8%–51.8%] for Vero Cell.CONCLUSIONThe patterns of antibody response to the causative agent in recipients with COVID-19 are comparable to those in immunocompetent patients, while for vaccinated recipients, a low frequency of detection of antiviral antibodies was shown, which indicates the need to continue research on the humoral immunity in people with vulnerable immunity in order to select the best tactics for COVID-19 immunization.

Comparison of CLEIA and ELISA for SARS-CoV-2 Virus Antibodies after First and Second Dose Vaccinations with the BNT162b2 mRNA Vaccine.

The global severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has required rapid action to control its spread and vaccines are a fundamental solution to this pandemic. The development of rapid and reliable serological tests to monitor the antibody response to coronavirus disease vaccines is necessary for post-vaccination immune responses. Therefore, in this study, anti-SARS-CoV-2 antibody titers after the first and second doses were monitored using two different measurement systems, a highly sensitive analytical platform of chemiluminescent enzyme immunoassay (CLEIA) and an enzyme-linked immunosorbent assay (ELISA). Our study included 121 participants who received two doses of the BNT162b2 vaccine. Both methods show significant increase in anti-spike protein IgG antibody levels one week after the first vaccination, and then reached at a plateau at week five (week two after the second dose), with a 3.8 × 103-fold rise in CLEIA and a 22-fold rise in ELISA. CLEIA and ELISA showed a good correlation in the high titer range, >10 binding antibody unit (BAU)/mL. Both methods detected higher IgG antibody levels in females compared with male participants after the second vaccination, while CLEIA exhibits the sex difference after the first dose. Thus, our study showed better performance of CLEIA over ELISA in sensitivity, especially in the low concentration range, however ELISA was also useful in the high titer range (>10 BAU/mL) corresponding to the level seen several weeks after the first vaccination.

Fever after Vaccination against SARS-CoV-2 with mRNA-Based Vaccine Associated with Higher Antibody Levels during 6 Months Follow-Up.

Background: The effect of post-vaccination adverse events on immunogenicity is unknown. We aimed to explore relationship between post-vaccination adverse reactions and antibody levels during 6-month follow-up. Methods: Blood was serially drawn from healthcare workers after the second dose of BNT162b2 mRNA vaccine (Day 12, 30, 60, 90, 120, 150, and 180) and anti-SARS-CoV-2 spike IgG (S-IgG) levels were measured. Following each vaccine dose, volunteers completed a questionnaire regarding adverse reactions (symptomatic vs. asymptomatic groups). Results: A total of 395 subjects received the second dose of the vaccine. The main results were as follows: (i) fever after the 2nd dose was independently associated with the median S-IgG level at all follow-up time points; (ii) significantly higher S-IgG levels were observed in the symptomatic group of patients without prior COVID-19 infection throughout the entire follow-up period; (iii) prior COVID-19 positivity resulted in higher S-IgG levels only in the asymptomatic group from Day 90 of the follow-up period; (iv) both prior COVID-19 disease with asymptomatic status and symptomatic status without prior COVID-19 infection resulted in similar S-IgG antibody levels; (v) significantly lower serum S-IgG levels were observed in smokers. Conclusion: Fever may play an important role in the post-vaccination immune response in the long term.

Humoral and Cellular Immune Responses of Solid Organ Transplant Patients on Belatacept to Three Doses of mRNA-Based Anti-SARS-CoV-2 Vaccine.

Background: Two doses of anti-SARS-CoV-2 mRNA-based vaccines are poorly immunogenic in solid organ transplant recipients (SOT). Methods: In total, 68 belatacept-treated SOT recipients followed at the Toulouse University Hospital were investigated. They were given three injections of the BNT162b2 mRNA COVID-19 vaccine. Their humoral response was assessed by determining anti-spike antibodies and neutralizing antibodies. The T-cell responses were assessed using an enzyme-linked immunospot assay that measured the interferon-γ produced by specific SARS-CoV-2 T-cells in a subgroup of 17 patients. Results: Only 23.5% of these patients developed a detectable anti-spike response. Moreover, the cellular and the humoral responses were well correlated. Patients with no humoral response were also without a detectable cellular response. Those belatacept-treated patients who developed an Anti-SARS-CoV-2 humoral response were younger, had been transplanted for longer, and had a higher lymphocyte count and a better glomerular filtration rate than those with no response. Finally, patients on tacrolimus plus belatacept produced a lower immune response. Conclusions: Belatacept-treated SOT recipients have a reduced immune response to anti-SARS-CoV-2 mRNA vaccination. The vaccine should be given quite separately from the belatacept infusion to improve immunogenicity. Studies to assess whether switching to another immunosuppressive regimen can improve the post-vaccination immune response would be useful.

COVID-19 Vaccines: An Overview of Different Platforms

Vaccination is one of the key strategies to stop the COVID-19 pandemic. This review aims to evaluate the current state of vaccine development and to determine the issues that merit additional research. We conducted a literature review of the development of COVID-19 vaccines, their effectiveness, and their use in special patient groups. To date, 140 vaccines are in clinical development. Vector, RNA, subunit, and inactivated vaccines, as well as DNA vaccines, have been approved for human use. Vector vaccines have been well studied prior to the COVID-19 pandemic; however, their long-term efficacy and approaches to scaling up their production remain questionable. The main challenge for RNA vaccines is to improve their stability during production, storage, and transportation. For inactivated vaccines, the key issue is to improve their immunogenicity and effectiveness. To date, it has been shown that the immunogenicity of COVID-19 vaccines directly correlates with their clinical efficacy. In view of the constant mutation, the emerging new SARS-CoV-2 variants have been shown to be able to partially escape post-vaccination immune response; however, most vaccines remain sufficiently effective regardless of the variant of the virus. One of the promising strategies to improve the effectiveness of vaccination, which is being studied, is the use of different platforms within a single vaccination course. Despite significant progress in the development and study of COVID-19 vaccines, there are many issues that require further research.

Toward the calibration of serological assays using sera collected from cattle and sheep following a single dose of foot-and-mouth disease vaccine.

Background and Aim:Serological assays are widely used to monitor the performance of foot-and-mouth disease (FMD) vaccines to estimate vaccination coverage and to ensure that vaccinated animals generate adequate immune responses. This study aimed to measure the FMD virus (FMDV)-specific responses in cattle and sheep after a single dose of a trivalent FMD vaccine containing serotypes A, O, and Asia-1, and to use these sera to calibrate virus neutralization tests (VNTs) and serotype-specific serological enzyme-linked immunoassays (ELISAs) that can measure post-vaccination responses.Materials and Methods:Sera were collected from cattle (n=10) and sheep (n=10) on 0, 21, and 56 days after immunization with an imported aqueous formulated FMD vaccine. These samples were tested by VNT using field FMDV isolates that are representative of the epidemiological risks in Central Asia (A/ASIA/Iran-05, A/ASIA/GVII, O/ME-SA/Ind-2001, O/SEA/Mya-98, O/ME-SA/PanAsia, and Asia-1 Shamir). Heterologous VNT antibody responses were compared to those measured using commercial FMDV-specific ELISAs for serotypes O, A, and Asia 1.Results:Administration of the FMD vaccine increased FMDV-specific antibody titers for both species in sera collected on day 21, but these elevated titers were short-lived and were decreased by day 56.Conclusion:These results highlight the short duration of immunity with a single dose of this aqueous vaccine and motivate further studies to assess immune responses in cattle and small ruminants after a two-dose course vaccination schedule. Further comparative data for VNT and serotype-specific ELISAs are needed to define cutoffs that can be used to monitor post-vaccination immune responses in low-containment laboratories where it is not possible to handle live FMDVs.