European Journal of Molecular & Clinical Medicine

Background: SARS CoV-2 infection took the whole world by storm in the final month of
2019.Different measures have been taken to reduce its spread by timely and accurate detection of
COVID 19(coronavirus disease 2019) infection in suspected patients and theircontacts.
Aim: This study was conducted to assess commercially available five Rt pcr (reverse
transcriptase polymerase chain reaction) kits from different manufacturers available in our center
for diagnostic testing ofSARS CoV-2 infection .94 oropharyngeal clinical samples,
previously confirmed as 64 positive and 30 negative for SARS CoV-2 were extracted and
amplified separately by each of the five Rt pcr kitsand the results compared.

Background: SARS CoV-2 infection took the whole world by storm in the final month of 2019.Different measures have been taken to reduce its spread by timely and accurate detection of COVID 19(coronavirus disease 2019) infection in  suspected    patients and theircontacts.
Aim: This study was conducted to assess commercially available five Rt pcr (reverse transcriptase polymerase chain reaction) kits from different manufacturers available in our center for diagnostic  testing  ofSARS CoV-2  infection  .94 oropharyngeal  clinical  samples, previously confirmed as 64 positive and 30 negative for  SARS CoV-2 were extracted and amplified separately by each of the five Rt pcr kitsand the results compared.
Results:The performance  of different kits was in  was satisfactory and above 90 percent in agreement with the  standard kit  for samples (n=47) with low Ct values  (Ct values<30) .  There was a significant variation in  performance among the five kits while  testing  high Ct values (Ct value >30) samples (n=17).Significant variation in Ct values of E gene ,RdRp  gene and N gene was observed in the Rt pcr kits results .
Conclusion:  We conclude that it is necessary to assess the diagnostic performance of different Rt pcr kits   for COVID 19 clinical samples from time to time to study the variation in Ct values, sensitivity of different gene targets  of SARS CoV2 virus, with proper co -ordination with other  laboratories , for development of reliable COVID 19 diagnostic centers at every level.

Background: SARS CoV-2 infection has become a major public health concern. India started Covid-19 vaccination from January 16, 2021, after the approval of two candidate vaccines namely COVISHIELD ™ and COVAXIN ™. The present study was conducted to see the neutralizing antibody response to trimeric S protein of SARS CoV-2 in health care workers (HCWs) with 2 doses of COVISHIELD vaccination in a tertiary care hospital.
Methodology: A prospective cohort study was conducted among 156 healthy adult health care workers in a tertiary care centre, vaccinated during January-March 2021. They were divided into two groups, the first group comprised of individuals who were previously RT-PCR positive (n=36) for SARS CoV-2, and second group comprised of those who were RT-PCR negative (n=120). Blood samples were collected from all participants, the first sample on the day of vaccination, second sample after 4 weeks of vaccination, and third after 8 weeks of vaccination to measure the IgG antibodies against the SARS CoV-2 ‘S’ protein using a chemiluminescent quantitative immunoassay.
Results: The spike protein-specific IgG antibody titre was demonstrated reactive cut-off in 98.3% of the participants after 2 doses of vaccine. The median antibody titre declined from 710.5 (IQR, 338.5-1577.5) to 266 (IQR, 116-557.75) in RT-PCR positive HCWs after 8 weeks of vaccination whereas it increased from 45.1 (IQR, 31.475-76.575) to 83.4 (IQR, 52.075-104) in RT-PCR negative HCWs.
Conclusion: We could demonstrate the development of an adequate spike protein-specific IgG titre against SARS CoV-2 following vaccination with 2 doses of COVISHIELD in HCWs.