The world’s first at-home Covid-19 test was approved (for emergency use) by the US Food and Drug Administration on Tuesday. Made by Lucira Health, this is a molecular test which is relatively inexpensive — according to the company’s website, it will cost under $50 — and quick (30 minutes). The company also claims that the product was 94% as accurate as the gold-standard RT-PCR test in identifying positive cases and 98% as accurate in identifying negative ones, which makes the home test fast, relatively cheap, and accurate.
On Wednesday, news reports said the Feluda test, developed by the Council for Scientific and Industrial Research’s Institute of Genomics and Integrative Biology, would be launched in Delhi, but only for use in laboratories. The test, which uses CRISPR (Dispatch 177 on October 8 wrote extensively about both the relevance of CRISPR at this time and on this test), can also be done at home, but it looks like a home version could take some time.
Also Read: Feluda test kit set to hit the market on Thursday
The Lucira test uses a technology called RT-LAMP or Reverse Transcription Loop Mediated Isothermal Amplification. Molecular tests respond to the genetic material of the virus, ribonucleic acid, or RNA. But before they do this, RNA has to be converted into complementary DNA, or cDNA, which is achieved using an enzyme called Reverse Transcriptase and a process called Reverse Transcription (it’s the reason many people use the terms interchangeably). LAMP then amplifies the cDNA, which is what shows up in the final result. In the case of the Lucira test, this is through a unit whose LED indicators change colour.
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Accurate, inexpensive, rapid tests hold the key to getting the pandemic under control. Accurate, inexpensive, rapid, home tests are even better. RT-LAMP tests aren’t based on some new breakthrough technology, though. They have been around for years. Back in May, India’s health minister, Harsh Vardhan, announced that a CSIR lab would work with an arm of India’s largest industrial conglomerate Reliance to commercialise its own rapid and inexpensive RT-LAMP tests for Covid. That hasn’t happened yet, though, in October, a Kochi-based company, Agappe Diagnostics, launched its own LAMP test for Covid-19, albeit for use in laboratories. Agappe’s test has been approved by the Indian Council of Medical Research.
It’s possible that the announcement of an approval for Lucira’s home test could open the floodgates; reliable home tests will remove a critical bottleneck in the current testing and diagnosis process, helping break the chain of infections. India’s health ministry and ICMR should work towards making accurate home tests available for those who need them (read that as those with symptoms, or those who have been exposed to an infected person; the FDA has said that Lucira’s home test will require a doctor’s prescription).
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PS: I usually avoid post scripts, but a recent paper (based on research) sheds more light on the immunity of those already infected by Covid-19 to reinfection, something Dispatch 204 on November 13 dealt with in the context of the findings of the latest round of Delhi’s sero survey. In the paper, uploaded on November 16 on pre-print server bioRXiv, researchers at the La Jolla Institute for Immunology, California, and others, claim (on the basis of a study of 185 Covid-19 patients) that many patients retain immune cells capable of recognising and fighting the disease even six months after infection. This adds to a growing volume of evidence that while infected people may show no trace of specific antibodies that fight the Sars-CoV-2 virus after some time, this does not mean a loss of immunity, with many possessing B-cells and T-cells that can remember and fight the virus. Theoretically, this means that vaccines should provide the same length of protection.