ABSTRACT
BackgroundThe magnitude of protection conferred after recovery from COVID-19 or by vaccine administration, and the duration of protective immunity developed, remains ambiguous. MethodsWe investigated the factors associated with antibody decay in 519 individuals who received treatment for COVID-19-related illness or received COVID-19 vaccination with two commercial vaccines, viz., an adenoviral vector-based (AZD1222) and a whole-virion-based inactivated (BBV152) vaccine in Chennai, India from March 2021. Blood samples collected during regular follow-up post-infection/vaccination andwere examined for anti-SARS-CoV-2 IgG by a commercial automated chemiluminescent immunoassay (CLIA). ResultsAge and underlying comorbidities were the two variables that were independently associated with the development of breakthrough infection. Individuals who were >60 years of age with underlying comorbid conditions had a [~]15 times and [~]10 times greater risk for developing a breakthrough infection and hospitalization, respectively. The time elapsed since the first booster dose was associated with attrition in anti-SARS-CoV-2 IgG, where each month passed was associated with an ebb in the neutralizing antibody levels by a coefficient of -6 units. ConclusionsOur findings advocate that the elderly with underlying comorbidities require a second booster dose with AZD1222 and BBV152.
ABSTRACT
Emergence of Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2) Variants of Concern (VOC) possessing improved virulence, transmissibility and/or immune-escape capabilities has raised significant public health concerns. In order to identify VOCs, WHO recommends Whole-Genome Sequencing approach, which is costly and involves longer completion time. Hence, potential role of commercial multiplex RT-PCR kit to screen variants rapidly is being attempted in this study. A total of 1200 suspected COVID samples from different districts of Tamil Nadu State (India) were screened with Thermo TaqPath RT-PCR kit and Altonas Realstar RT-PCR Assay kit. Among 1200 screened, S-gene target failure (SGTF) phenomenon were identified in 112 samples while testing with TaqPath RT-PCR Kit. 100% concordant results were observed between SGTF phenomenon and whole-genome sequencing (WGS) results in detecting SARS-CoV-2 VOC B.1.1.7. TaqPath RT-PCR assay testing can be utilized by laboratories to screen rapidly the VOC B.1.1.7 variants, thus enabling early detection of B.1.1.7 variant infection and transmission in population. This in turn will pave way to implement suitable preventive measures by appropriate authorities to control the transmission of the viral variant.
ABSTRACT
Four rounds of serological surveys were conducted, spanning two COVID waves (October 2020 and April-May 2021), in Tamil Nadu (population 72 million) state in India. Each round included representative populations in each district of the state, totaling [≥]20,000 persons per round. State-level seroprevalence was 31.5% in round 1 (October-November 2020), after Indias first COVID wave. Seroprevalence fell to 22.9% in 2 (April 2021), consistent with waning of antibodies from natural infection. Seroprevalence rose to 67.1% by round 3 (June-July 2021), reflecting infections from the Delta-variant induced second COVID wave. Seroprevalence rose to 93.1% by round 4 (December 2021-January 2022), reflecting higher vaccination rates. Antibodies also appear to wane after vaccination. Seroprevalence in urban areas was higher than in rural areas, but the gap shrunk over time (35.7 v. 25.7% in round 1, 89.8% v. 91.4% in round 4) as the epidemic spread even in low-density rural areas. Article Summary LineAntibodies waned after Indias first COVID wave and both vaccination and infection contributed its roughly 90% seroprevalence after its second wave.
