COVID-19 testing determines the presence of SARS-CoV-2 virus or antibodies developed after infection. Molecular tests detect viral components, diagnosing cases and enabling outbreak tracing. Antibody tests reveal past infection but are less reliable for current diagnoses as antibody development takes time. Antibody testing helps estimate disease prevalence and infection fatality rates.
In 2003, Drosten et al. highlighted that nasal and throat swabs might not be the most effective for COVID-19 diagnosis. They found that these samples contained less viral RNA compared to sputum, potentially leading to false negatives.
Korea's experience with the MERS outbreak in May 2015 influenced its preparedness for COVID-19, with established systems for isolation, testing, and treatment.
In 2016, then-President Park Geun-hye authorized Korean CDC-approved private sector testing for infectious diseases, contributing to the country's testing capacity.
In January 2020, a significant breakthrough occurred when scientists from China shared the first genetic sequences of SARS-CoV-2. This data enabled researchers worldwide to develop molecular tests, marking a crucial step in understanding and combating the virus.
In April 2020, Russia conducted mass COVID-19 testing, with 3 million people tested and 183,000 positive results. Findings showed 45% of those testing positive were asymptomatic, and family transmission was common. Antibody testing revealed 20% immunity among Moscow doctors.
In April 2020, discussions arose about the potential of antigen tests as a viable option for large-scale COVID-19 testing. Deborah Birx, head of the White House Coronavirus Task Force, acknowledged the limitations of PCR tests in terms of scalability and highlighted the potential of antigen tests to address this challenge.
In April 2020, economist Paul Romer suggested that the US had the capacity to significantly increase its daily COVID-19 testing capacity to 20 million tests. He highlighted single-molecule real-time sequencing and Ion Torrent Next-Generation Sequencing technologies as potential solutions.
In May 2020, a review of PCR-RT testing found that the median probability of a false-negative result was highest on day 1 of infection and decreased over time. The probability was 38% on the day of symptom onset and decreased to 20% three days later.
The Edmond J. Safra Center for Ethics estimated that the proposed increase in US testing capacity, as suggested by economist Paul Romer, could be achieved by late July 2020. This projection highlighted a potential timeline for expanding testing capabilities.
In July 2020, Dr. Anthony Fauci of the US NIH suggested that positive results from RT-PCR tests run at over 35 cycles were likely insignificant.
In a significant development in August 2020, the US FDA granted emergency use authorization for a saliva-based COVID-19 test developed by Yale University, offering a faster turnaround time for results.
In August 2020, the World Health Organization (WHO) acknowledged the potential value of wastewater surveillance as a tool to monitor the prevalence and trends of COVID-19 within communities. They highlighted its role as a potential early warning system, particularly as vaccination rates increase and traditional testing methods evolve.
In August 2020, reports emerged about varying cycle threshold limits for PCR tests and the CDC's consideration of these measures for policy decisions.
In October 2020, Slovakia conducted mass COVID-19 testing, covering 67% of the population. The government aimed to control the virus spread and avoid a lockdown, with potential for repeat testing.
Slovakia undertook a large-scale COVID-19 testing initiative in October 2020, aiming to test a significant portion of its population within a short period. While this initiative led to a decrease in observed prevalence, questions arose about the long-term impact and the potential for a false sense of security among those testing negative.
In 2020, Nevada received a donation of Chinese-made COVID-19 testing kits. However, the US Department of Homeland Security and State Department raised concerns about their use, citing potential issues with test accuracy, data privacy, and the involvement of the Chinese government.
A 2020 study revealed significant variations in the accuracy of the Innova SARS-CoV-2 Antigen Rapid Test depending on who administered it. The study found a higher accuracy rate when used by laboratory professionals compared to the general public, raising concerns about the test's reliability in different settings.
In January 2021, Denmark temporarily halted flights from the UAE due to concerns about potential irregularities in the COVID-19 testing process, raising doubts about the accuracy of negative test results.
In January 2021, the US FDA issued a warning about the accuracy of the Curative SARS-CoV-2 Assay real-time RT-PCR test, specifically highlighting the risk of false-negative results, raising concerns about the reliability of certain testing methods.
On January 4, 2021, the US FDA issued an alert highlighting the risk of inaccurate results, especially false negatives, with the Curative SARS-CoV-2 Assay real-time RT-PCR test.
The Innova SARS-CoV-2 Antigen Rapid Qualitative Test, widely distributed but unapproved for use in the United States, was recalled in April 2021. The FDA cited concerns about inadequate quality assurance and a higher rate of false results than claimed.
In May 2021, researchers explored innovative approaches to COVID-19 detection. A study by Dutch researchers revealed that trained bees could identify infected samples quickly, offering a potential solution for areas with limited testing resources. Separately, a French study indicated that dogs exhibited a higher accuracy rate than lateral flow tests in detecting the virus.
On July 21, 2021, the CDC recommended in their "Real-Time RT-PCR Diagnostic Pan: Instructions for Use" that test results be determined at 40 cycles.
Despite the recall in the US, the UK continued to use the Innova SARS-CoV-2 Antigen Rapid Test under exceptional authorization until at least August 2021, raising concerns among experts about its accuracy, particularly when used for screening asymptomatic individuals.
As of 2021, the reverse transcription polymerase chain reaction (RT-PCR) test was the most common molecular test used to detect the presence of the virus's RNA.
In March 2022, a study in Paris suggested that trained dogs could be highly effective in rapidly identifying SARS-CoV-2 in individuals, regardless of symptom presentation. The study indicated that dogs could accurately detect the virus by smelling sweat samples, even in asymptomatic cases, offering a potential non-invasive and quick testing method.
By 2023, home-based testing had become more prevalent, with Hong Kong implementing systems for individuals to receive and submit samples from home. The United States also conducted multiple rounds of distributing free at-home COVID-19 tests, including rapid antigen tests that did not require lab analysis, highlighting efforts to expand testing access.