Agrima Bhatt, Rajasthan University
In the surge of COVID-19 infection, the healthcare system has been put under immense pressure and the response has been nothing short of developing and innovative. While the rate of people diagnosed with infection has decreased exponentially, the testing remains constant. Effective testing at the time of the pandemic has been the key for scientists to gain an understanding of the virus, which later played a crucial role in vaccine development for COVID-19. However, in many developing countries, improper testing protocols have led to failure in containing the community spread of SARS-CoV-2 in many countries. Even with the development of effective vaccines against SARS-CoV-2, controlling the fast mutating pace of the virus has proven to be challenging due to slow vaccine rollouts, incomplete vaccine protection to the emerging variants, and hesitancy across the population to get vaccinated.
RT-PCR tests are currently the standard tests to detect the genetic material of viruses inside the human body. At present, over 392 million samples have been tested in India and above 400 million tests have been done in the USA. Currently, RT-PCR tests are only able to be performed in the central laboratory, which makes the testing process not only rigorous but also places workload and mental stress on the lab technicians. However, scientists are continuously working to develop effective strategies for frequent testing and ‘rapid’ tests with quick results. The development of home-based diagnosis using ‘rapid’ tests based on the detection of viral antigens from self-collected nasal swabs was a unique feature. The tests offered quick results but it was only able to detect 20,000 viral RNA copies per microliter.
WHotLAMP – An Inexpensive Rapid Diagnostic test
Recently, researchers from the USA were able to develop a specific molecular diagnostic test for the detection of SARS-CoV-2 in saliva. WHotLAMP is a cheap, rapid, sensitive molecular diagnostic test that can detect up to 3.6 viral RNA copies per microliter of saliva. Its application does not require the usage of any toxic chemical or any special machinery which makes it especially useful for point-of-care settings. In the future, it can also be adapted to home settings as well as to detect any other pathogen, in case of any more future pandemics. WHotLAMP can detect low levels of SARS-CoV-2 virus in saliva samples in under the duration of only 30 minutes. Its design is user-friendly with the single-tube format requiring no centrifugation of the sample.
WHotLAMP Primers highly specific to SARS-CoV-2
The researchers have created LAMP primer sets over the whole SARS-CoV-2 genome, focusing on the set with the lowest predicted probability for primer-dimer formation. They found SARS-CoV-2 RNA in the samples containing encapsulated SARS-CoV-2 RNA particles but not in any of the samples containing any other respiratory infections or their pathogens, demonstrating the primers SARS-CoV-2 specificity. This molecular diagnostic test kit is specifically developed at present for the SARS-CoV-2 pandemic which is infiltrating and has had an impact globally over the last 2 years, but it can also be used to detect other pathogens present in the saliva simply by substituting primers and thereby enhancing its broad prospects in future.
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References:
- Ng, D., Pinharanda, A., Vogt, M. c., Litwin-Kumar, A. et al. WHotLAMP: A Simple, Inexpensive, and Sensitive Molecular Test for the Detection of SARS-CoV-2 in Saliva. medRxiv (2021). doi:10.1101/2021.06.17.21259050.
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