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1.
Trials ; 23(1): 92, 2022 Jan 31.
Article in English | MEDLINE | ID: covidwho-1662422

ABSTRACT

The SARS-CoV-2 enters into the human body mainly through the nasal epithelial cells. Prevention of SARS-CoV-2 infection at the point of nasal entry is a novel strategy that has the potential to help contain the ongoing pandemic. BioBlock is a nasal spray of anti-SARS-CoV-2 preparation based on virus-neutralising antibodies prepared from colostrum from cows immunised with SARS-CoV-2 spike protein. This triple-blind placebo-controlled cluster randomised parallel trial seeks to evaluate the efficacy of a BioBlock spray in the prevention and treatment of SARS-CoV-2 infection. Laboratory-confirmed COVID-19 cases and their household members will be randomly allocated to each of either the intervention (BioBlock nasal spray) or the placebo (nasal spray) arms. The intervention is a 14-day course of nasal spray used by index case and household contacts. In most countries, those with confirmed or suspected infections are requisitioned to isolate at home, putting other members of their household at risk of infection. Therefore, in parallel to the need of household transmission prevention measures, households also present as a good model for infection transmission studies, allowing for the testing of several close contact transmission prevention study hypotheses. Our hope is that if the trial results are encouraging, this will provide new and additional COVID-19 prevention strategies. TRIAL REGISTRATION: ISRCTN48554326 Registered on June 14, 2021.


Subject(s)
COVID-19 , Animals , Cattle , Colostrum , Female , Humans , Pregnancy , Randomized Controlled Trials as Topic , SARS-CoV-2 , Spike Glycoprotein, Coronavirus
2.
Front Immunol ; 12: 709759, 2021.
Article in English | MEDLINE | ID: covidwho-1450807

ABSTRACT

The clinical features of SARS-CoV-2 infection range from asymptomatic to severe disease with life-threatening complications. Understanding the persistence of immune responses in asymptomatic individuals merit special attention because of their importance in controlling the spread of the infections. We here studied the antibody and T cell responses, and a wide range of inflammation markers, in 56 SARS-CoV-2 antibody-positive individuals, identified by a population screen after the first wave of SARS-CoV-2 infection. These, mostly asymptomatic individuals, were reanalyzed 7-8 months after their infection together with 115 age-matched seronegative controls. We found that 7-8 months after the infection their antibodies to SARS-CoV-2 Nucleocapsid (N) protein declined whereas we found no decrease in the antibodies to Spike receptor-binding domain (S-RBD) when compared to the findings at seropositivity identification. In contrast to antibodies to N protein, the antibodies to S-RBD correlated with the viral neutralization capacity and with CD4+ T cell responses as measured by antigen-specific upregulation of CD137 and CD69 markers. Unexpectedly we found the asymptomatic antibody-positive individuals to have increased serum levels of S100A12, TGF-alpha, IL18, and OSM, the markers of activated macrophages-monocytes, suggesting long-term persistent inflammatory effect associated with the viral infection in asymptomatic individuals. Our results support the evidence for the long-term persistence of the inflammation process and the need for post-infection clinical monitoring of SARS-CoV-2 infected asymptomatic individuals.


Subject(s)
Antibodies, Viral/blood , Asymptomatic Infections , CD4-Positive T-Lymphocytes/immunology , COVID-19/pathology , Inflammation Mediators/blood , SARS-CoV-2/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , CD4 Lymphocyte Count , Coronavirus Nucleocapsid Proteins/immunology , Humans , Inflammation/immunology , Interleukin-18/blood , Macrophages/immunology , Monocytes/immunology , Oncostatin M/blood , Phosphoproteins/immunology , Protein Domains/immunology , S100A12 Protein/blood , Spike Glycoprotein, Coronavirus/immunology , Transforming Growth Factor alpha/blood
3.
Infect Dis (Lond) ; 54(1): 63-71, 2022 01.
Article in English | MEDLINE | ID: covidwho-1406440

ABSTRACT

BACKGROUND: In a country-wide seroprevalence study of COVID-19 in Estonia, we aimed to determine the seroprevalence and the dynamics of IgG against SARS-CoV-2 after vaccination or positive PCR-test. METHODS: Leftover blood samples were selected between 8 February and 25 March 2021, by SYNLAB Estonia from all counties and age groups (0-9, 10-19, 20-59, 60-69, 70-79 and 80-100 years) proportionally to the whole Estonian population and tested for IgG against SARS-CoV-2 spike protein receptor-binding domain (anti-S-RBD IgG) using Abbott SARS-CoV-2 IgG II Quant assay. Antibody levels after positive PCR-test or vaccination were described by exponential increase-decrease models. RESULTS: According to total of 2517 samples, overall seroprevalence (95% confidence interval [CI]) was 20.1% (18.5-21.7%), similar in all age groups, but varied between counties. If individuals vaccinated with the first dose at least 14 d before antibody measurement were assumed to be seronegative, the overall seroprevalence was 15.8% (14.4-17.3%), 4.0-fold larger than the proportion of PCR-confirmed COVID-19 cases. Of seropositive individuals (n = 506) 194 (38.3%; 33.8-43.1%) had not had positive PCR-test or been vaccinated. According to exponential increase-decrease model, the peak of anti-S-RBD IgG in a 52-year-old (median age of PCR-positive and/or vaccinated individuals) was significantly higher after vaccination compared with positive PCR-test (22,082 (12,897-26,875) vs. 6732 (2321-8243) AU/mL), but half-life was similar (26.5 (6.9-46.1) vs. 38.3 (8.2-68.5) d). CONCLUSIONS: One year after the start of COVID-19 pandemic the actual prevalence of infection is still underestimated compared with PCR-confirmed COVID-19 cases. Older compared with younger individuals have lower anti-S-RBD IgG level after vaccination, but similar decline rate.


Subject(s)
Antibodies, Viral/blood , COVID-19 Vaccines/immunology , COVID-19 , Immunoglobulin G/blood , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/immunology , COVID-19/prevention & control , Child , Child, Preschool , Estonia , Humans , Infant , Infant, Newborn , Middle Aged , Pandemics , Seroepidemiologic Studies , Spike Glycoprotein, Coronavirus/immunology , Vaccination , Young Adult
4.
Vaccine ; 39(38): 5376-5384, 2021 09 07.
Article in English | MEDLINE | ID: covidwho-1340875

ABSTRACT

PURPOSE: In Estonia, during the first wave of COVID-19 total number of cases confirmed by PCR was 13.3/10,000, similar in most regions, including capital Tallinn, but in the hotspot of Estonian epidemic, an island Saaremaa, the cumulative incidence was 166.1/10,000. We aimed to determine the prevalence of SARS-CoV-2 IgG antibodies in these two regions, symptoms associated with infection and factors associated with antibody concentrations. METHODS: Participants were selected using stratified (formed by age decades) random sampling and recruited by general practitioners. IgG or neutralizing antibodies were determined from sera by four assays. Symptoms associated with seropositivity were analyzed by multiple correspondence analysis, antibody concentrations by multiple linear regression. RESULTS: Total of 3608 individual were invited and 1960 recruited from May 8 to July 31, 2020. Seroprevalence was 1.5% (95% confidence interval (CI) 0.9-2.5) and 6.3% (95% CI 5.0-7.9), infection fatality rate 0.1% (95% CI 0.0-0.2) and 1.3% (95% CI 0.4-2.1) in Tallinn and Saaremaa, respectively. Of seropositive subjects 19.2% (14/73) had acute respiratory illness. Fever, diarrhea and the absence of cough and runny nose were associated with seropositivity in individuals aged 50 or more years. IgG, but not neutralizing antibodies concentrations were higher if fever, difficulty breathing, shortness of breath, chest pain or diarrhea was present, or hospitalization required. CONCLUSION: Similarly to other European countries the seroprevalence of SARS-CoV-2 in Estonia was low even in the hotspot region Saaremaa suggesting that majority of population is susceptible to SARS-CoV-2. Focusing only on respiratory symptoms may delay accurate diagnosis of SARS-CoV-2 infection.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Estonia/epidemiology , Humans , Immunoglobulin G , Prevalence , Seroepidemiologic Studies
5.
PLoS One ; 15(10): e0237548, 2020.
Article in English | MEDLINE | ID: covidwho-892379

ABSTRACT

SARS-CoV-2 antibody tests are available in various formats, detecting different viral target proteins and antibody subclasses. The specificity and sensitivity of SARS-CoV-2 antibody tests are known to vary and very few studies have addressed the performance of these tests in COVID-19 patient groups at different time points. We here compared the sensitivity and specificity of seven commercial (SNIBE, Epitope, Euroimmun, Roche, Abbott, DiaSorin, Biosensor) and two in-house LIPS assays (LIPS N and LIPS S-RBD) IgG/total Ab tests in serum samples from 97 COVID-19 patients and 100 controls, and correlated the results with the patients' clinical data and the time-point the test was performed. We found a remarkable variation in the sensitivity of antibody tests with the following performance: LIPS N (91.8%), Epitope (85.6%), Abbott and in-house LIPS S-RBD (both 84.5%), Roche (83.5%), Euroimmun (82.5%), DiaSorin (81.4%), SNIBE (70.1%), and Biosensor (64.9%). The overall agreement between the tests was between 71-95%, whereas the specificity of all tests was within 98-100%. The correlation with patients' clinical symptoms score ranged from strongest in LIPS N (ρ = 0.41; p<0.001) to nonsignificant in LIPS S-RBD. Furthermore, the time of testing since symptom onset had an impact on the sensitivity of some tests. Our study highlights the importance to consider clinical symptoms, time of testing, and using more than one viral antigen in SARS-CoV-2 antibody testing. Our results suggest that some antibody tests are more sensitive for the detection of antibodies in early stage and asymptomatic patients, which may explain the contradictory results of previous studies and should be taken into consideration in clinical practice and epidemiological studies.


Subject(s)
Antibodies, Viral/blood , Betacoronavirus/immunology , Clinical Laboratory Techniques , Coronavirus Infections/immunology , Immunoglobulin G/blood , Pandemics , Pneumonia, Viral/immunology , Serologic Tests/methods , Adult , Age Factors , Aged , Aged, 80 and over , Antibody Specificity , Antigens, Viral/immunology , Asymptomatic Infections/epidemiology , COVID-19 , COVID-19 Testing , Coronavirus Infections/blood , Coronavirus Infections/diagnosis , Disease Progression , False Positive Reactions , Female , Humans , Male , Middle Aged , Pneumonia, Viral/blood , RNA, Viral/blood , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Sensitivity and Specificity , Symptom Assessment , Young Adult
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