ABSTRACT
Conflicting reports on the persistence of antibody levels in individuals recovered from COVID-19 infection, suggest that the immunity against COVID-19 may not be lasting for long. In India, by 30th June, 2021, not less than 30 million people were infected with COVID-19 and 0.39 million people were reported to have lost their life to the disease in India. I the current study we followed up with a subsample of our previous sero-survey participants to assess whether natural immunity against SARS-CoV-2 was associated with a reduced risk of re-infection. We conducted telephonic interview of a total of 3038 participants, out of which 2238 participants responded and 5 participants were found to be not alive, as conveyed by their close relatives. There was a non-response rate of 26.1%. Out of the 2238 participants, 1170 were sero-positive and 1068 were sero-negative for antibody against COVID-19. Our survey found that only 3 individuals in the sero-positive group got infected with COVID-19 whereas 127 individuals reported contracting the infection the sero-negative group. Interestingly, from the 127 sero-negative individuals who later contracted COVID-19 infection, 30 needed hospitalization, out of which 12 were on oxygen therapy, four in ICU and one was on ventilator. At the other hand, from the 3 sero-positives re-infected with COVID-19, one had hospitalization, but didnnot require oxygen support or critical care. These findings reinforce the strong plausibility that development of antibody following natural infection not only protects against re-infection by the virus to a great extent, but also safeguards against progression to severe COVID-19 disease.
ABSTRACT
BackgroundHealth care workers (HCWs) are the most susceptible group to get COVID-19 infection and this group always need special attention as they are the key human resource to contain this pandemic. ObjectiveTo track down the seroprevalence among a particular group of HCWs working in the anaesthesia department in hospital settings. Study designTwo rounds of serosurvey were done to track the dynamicity among the 128 and 164 HCWs participants in the first round and second round, respectively. 5 mL of blood was collected and anti-SARS-CoV-2 IgG antibody was tested in Abbott Architect i1000SR. ResultsThe seroprevalence found in the first and second round was 12.5% and 38.4%, respectively. A significant number (n=61, 77.21%) of seropositivity came from the asymptomatic HCWs group as found in both the survey. There was no significant association among different age, gender and RT-PCR tested groups. ConclusionRoutine diagnosis of COVID-19 should be referred among HCWs to identify and act upon unrecognized SARS-CoV-2 infection.
ABSTRACT
The SARS-CoV-2 antibody responses remain poorly understood and the clinical utility of serological testing is still unclear. As it is thought to confer some degree of immunity, this study is carried out to know the relationship between demographics and ct value of confirmed rt-PCR patients. A total of 384 serum samples were collected between 4-6 weeks after confirmed SARS-CoV-2 infection. IgG positivity was found to be 80.2% (95% CI, 76.2 - 84.2). The IgG positivity increased with the decrease in the ct value, with highest of 87.6% positivity in individuals with <20 ct value. The mean ({+/-} SD) ct value of IgG positives and og IgG negatives was 23.34 ({+/-} 6.09) and 26.72 ({+/-} 7.031) respectively. There was no significant difference found between the demographic characteristics such as age, sex, symptoms and antibody response. The current study is first of its kind wherein we have assessed the correlation of ct of RT-PCR with development of IgG against SARS-CoV-2. Our study showed that although Ct value might not have any relation with severity of the diseases but is associated with the antibody response among the SARS-CoV-2 infected individual.
ABSTRACT
BackgroundThere is always an uncertainty of epidemiological, serological infectivity and virulence of the emerging novel coronavirus. Antibody test can be used for assessing whether immunity has developed in the infected person after 5-7 days of illness and understand cumulative exposure levels to the infection, make inferences on the actual burden of infection, its geographical spread, effect on specific demographic/risk groups, gaps in testing and infection fatality rates. ObjectiveTo estimate and compare the sero-prevalence, hidden prevalence and determine the demographic risk factors associated with SARS-CoV-2 infection among adults in three largest cities of Odisha, India. MethodologyThis was a population based cross sectional serological survey carried out in August 2020 in the three largest cities of the state of Odisha. Sample size per city was estimated to be 1500 and participants were enrolled from the community using multi-stage random sampling from 25 clusters from each city. Data was collected using ODK based tools by household visits and 3-4 ml of blood samples were collected after informed consent. Samples were transported to testing lab where Serum was separated and tested for anti-SARS CoV-2 antibodies using automated CLIA platform. Statistical analysis was done using R-software packages. ResultsA total of 4146 participants from the 3 cities of Bhubaneswar (BBS), Berhampur (BAM) and Rourkela (RKL) participated. A total of 5635 households were approached and the average non response rate in the community was 17.4%. The gender weighted seroprevalence across the three cities was 20.78% (95% CI: 19.56%-22.05%). Seroprevalence was highest in BAM at 31.14% (95% CI: 28.69-33.66%) followed by 24.59% (95% CI: 22.39-26.88%) in RKL and 5.24% (95% CI: 4.10-6.58%) in BBS. While females reported a higher seroprevalence (22.8%) as compared to males (18.8%), there was no significant difference in seroprevalence across age groups. A majority of the seropositive participants were asymptomatic (93.87%). Among those who reported symptoms, the most common symptom was fever (68.89%) followed by cough (46.06%) and myalgia (32.67%). The case to infection ratio on the date of serosurvey was 1: 6.6 in BBS, 1:61 in BAM and 1:29.8 in RKL. ConclusionThe study found a high seroprevalence against COVID-19 in urban Odisha as well as high numbers of asymptomatic infections.
ABSTRACT
The whole world is battling against coronavirus disease-19 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Various strategies are taken to curb the spread of the virus and to move out from the enforced lockdown stage. Serological tests are the neediest diagnostic and surveillance tool to complement the gold standard molecular diagnostic method to track down the transmission rate of SARS-CoV-2. Automated chemiluminescent immunoassay (CLIA) based analyzers become highly demanding platforms both to clinicians and policy makers for the detection anti-SARS-CoV-2 antibodies. In this study, serum from 594 patients positive for COVID-19 and 100 samples from pre-COVID cases were tested by three automated platforms: Abbott architect i2000SR, Roche cobas e411 and Yhlo iFlash 1800 and their diagnostic accuracy were compared. All three platforms showed high specificity as claimed by manufacturer. Clinical sensitivities of the machines were calculated as 64.48% (58.67-70.3) for Abbott, 80.48% (76.62-84.34) for Roche and 76.94% (72.65-81.23) for Yhlo. The Cohens kappa value was determined from 0.69-0.89 when inter-rater agreements were calculated. The area under the curves (AUC) values demonstrated Roche Cobas e411 as the diagnostically most accurate platform among the three CLIA analyzers.
ABSTRACT
Background It is almost nine months, still there is no sign to stop the spreading of the COVID-19 pandemic. Rapid and early detection of the virus is the master key to cease the rapid spread and break the human transmission chain. There are very few studies in search of an alternate and convenient diagnostic tool which can substitute nasopharyngeal swab (NPS) specimen for detection of SARS-CoV-2. We aimed to analyse the comparison and agreement between the feasibility of using the saliva in comparison to NPS for diagnosis of SARS-CoV-2. Methods A total number of 74 patients were enrolled for this study. We analysed and compared the NPS and saliva specimen collected within 48 h after the symptom onset. We used real time quantitative polymerase chain reaction (RT-qPCR), gene sequencing for the detection and determination SARS-CoV-2 specific genes. Phylogenetic tree was constructed to establish the isolation of viral RNA from saliva. We use Bland-Altman model to identify the agreement between two sampling methods. Findings This study shows a lower CT mean value for the detection of SARS-CoV-2 ORF1 gene (27.07; 95% CI, 25.62 to 28.52) in saliva methods than that of NPS (28.24; 95% CI, 26.62 to 29.85) sampling method. Bland-Altman analysis produces relatively smaller bias and high agreement between these specimen tools. Phylogenetic analysis with the RdRp and Spike gene confirmed the presence of SARS-CoV-2 in the saliva samples. Interpretation: In conclusion, our study highlights that saliva represents a promising tool in COVID-19 diagnosis and would reduce the exposure risk of frontline health workers which is one of biggest concern in primary healthcare settings.
ABSTRACT
In infectious diseases, the routes of transmission play major roles in determining the rate and extent of disease spread. Though fomites and aerosol droplets are major sources of SARS-CoV-2 human to human transmission, studies have also reported possible involvement of other routes of transmission like fecal-oral. Multiple studies around the world have reported shedding of the SARS-CoV-2 viral genome in certain COVID-19 patient fecal samples. Hence, the major objective of this study was to get the experimental evidence whether in Indian COVID-19 patients fecal dissemination of the SARS-CoV-2 genome occurs or not. Information obtained from twelve number of patients from a COVID-19 hospital of Odisha has demonstrated that both symptomatic and asymptomatic Indian patients could be positive for the SARS-CoV-2 genome in their fecal component. The findings have also established a protocol to collect and extract viral RNA for SARS-CoV-2 detection in fecal samples. Together, the study supports the hypothesis of possible fecal-oral transmission of SARS-CoV-2 virus and provides a rationale to extend this study in a larger cohort of patient samples and correlate the significance of the SARS-CoV-2 virus genome detection in fecal samples with disease severity and transmission.
