COVID-19 diagnostic methods in developing countries

Abstract

COVID-19 has become one of the few leading causes of death and has evolved into a pandemic that disrupts everyone’s routine, and balanced way of life worldwide, and will continue to do so. To bring an end to this pandemic, scientists had put their all effort into discovering the vaccine for SARS-CoV-2 infection. For their dedication, now, we have a handful of COVID-19 vaccines. Worldwide, millions of people are at risk due to the current pandemic of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2). Despite the lack of clinically authorized antiviral medications and vaccines for COVID-19, clinical trials of many recognized antiviral agents, their combination, and vaccine development in patients with confirmed COVID-19 are still ongoing. This discovery gave us a chance to get immune to this disease worldwide and end the pandemic. However, the unexpected capacity of mutation of the SARS-CoV-2 virus makes it difficult, like the recent SAS-CoV-2 Omicron variant. Therefore, there is a great necessity to spread the vaccination programs and prevent the spread of this dreadful epidemic by identifying and isolating afflicted patients. Furthermore, several COVID-19 tests are thought to be expensive, time-consuming, and require the use of adequately qualified persons to be carried out efficiently. In addition, we also conversed about how the various COVID-19 testing methods can be implemented for the first time in a developing country and their cost-effectiveness, accuracy, human resources requirements, and laboratory facilities. Graphical abstract

The Potential of Nanobodies for COVID-19 Diagnostics and Therapeutics

“…The RT-PCR technique is an accurate assay regularly utilized for SARS-CoV-2 detection and diagnosis [ 8 , 22 ]. Currently, there are various COVID-19 RT-PCR kits commercially available that target various viral genes (RdRp, E, N, S, ORF1ab, ORF1a, and ORF1b or ORF8) for detection [ 8 , 20 , 23 ]. Notably, RT-PCR has been considered the gold standard but there are advantages and challenges.…”

“…Notably, RT-PCR has been considered the gold standard but there are advantages and challenges. RT-qPCR provides reliability, flexibility, high sensitivity and specificity, however the challenges include false negatives, a lengthy and complex procedure, requirement of expensive equipment and trained personnel, sample quantities for RNA isolation, sample integrity, low viral load samples, and delivery time of results to patients (> 24 h) [ 23 , 24 ]. Additionally, mutations in the target regions have the potential to effect RT-PCR accuracy, resulting in test failures and false-negatives [ 20 ].…”

“…It is a fast and cheap method that is highly specific due to the use of 6–8 specific primer sequences that detect eight different regions [ 20 ]. Additionally, it can identify SARS-CoV-2 from swabs or saliva without the requirement of RNA isolation [ 23 ]. The RT-LAMP method is inexpensive, fast, and highly specific, however sensitivity is dependent on viral load [ 24 ].…”

“…The RT-LAMP method is inexpensive, fast, and highly specific, however sensitivity is dependent on viral load [ 24 ]. Notably, proper primer design and use of specific primers are essential to maximize sensitivity [ 23 ].…”

“…The ELISA method is a cost-effective quantitative, qualitative, highly specific, sensitive, efficient and simple procedure [ 23 ]. ELISAs are reliable, commercially available kits that mostly detect the S and N proteins [ 20 ].…”