Rapid Tests Play A Crucial Role Against COVID-19 Pandemic
With global attempts to return to some form of normalcy and the emergence of the Omicron variant, an individual’s risk of infection can now change from day to day and many people are left with uncertainty about attending events, activities, and gatherings. Together with vaccination, testing constitutes one of the most efficient ways to monitor and curb the spread of SARS-CoV-2. Taken as a step towards answering the peak of demand to testing, many countries authorized the use of COVID-19 rapid tests. Although less sensitive than PCR tests which constitute the gold standard of COVID-19 testing, rapid tests made testing more accessible, affordable, and convenient than ever. What benefits do rapid testing offer? Can the trade-off in accuracy be worth it? What are the long-term implications of rapid testing for the management of the pandemic? Here’s what to know about COVID-19 rapid testing.
Advantages of COVID-19 Rapid Testing
Instead of amplifying and identifying SARS-CoV-2 genome, rapid tests detect SARS-CoV-2- specific surface protein or antigen in the specimen by utilizing certain antibodies that recognize and bind to SARS-CoV-2 antigens. These kits are relatively inexpensive to produce, easy to administer, and they provide results within 15 to 30 minutes. As they do not require lab technology and personnel, they can be self-administered anywhere and as often as needed. All the components of the kit, along with storage guidelines and step-by-step instructions on how to perform the test are provided within the test kit. Moreover, the kits are easily available without a prescription online or at pharmacies and retail stores. However, although rapid antigen tests met certain standards regarding safety, performance, and accuracy, as the tests do not detect the SARS-CoV-2 genome and do not contain an amplifying process, they are relatively less sensitive than PCR tests in cases with low viral loads. Thus, especially in detection of SARS-CoV-2 in asymptomatic cases and in the early onset of the infection, PCR testing has significant accuracy. Altogether, despite their accessibility and affordability, rapid antigen tests do not replace PCR tests as the gold standard of COVID-19 testing and PCR tests are often required to confirm the results of rapid antigen tests.
Is the Trade-Off of Accuracy Worth the Benefits?
Antigen tests require a relatively high viral load to detect a SARS-CoV-2 infection. In cases where the virus has not had time to replicate enough after exposure, antigen tests may decline in accuracy. Still, recent research suggests that when it comes to public health and pandemic management, benefits of rapid antigen testing such as accessibility, frequent testing, immediate results, and rapid turnaround outweigh their relative deficiency in accuracy. Moreover, studies demonstrate that routine testing improves the overall accuracy of rapid antigen tests to a comparable level to that of PCR tests.
A study published in November 2020 aimed to determine whether test sensitivity, frequency or turnaround time is most important to curb the spread of COVID-19. The researchers examined the existing literature on changes in viral load and viral transmissibility. Then, they have used mathematical modeling to evaluate the impact of screening with different kinds of tests on three hypothetical scenarios concerning 10.000 individuals, a university-type setting of 20,000 people, and a city with a population of 8.4 million. Their findings indicate that frequency and turnaround time are much more important than test sensitivity regarding curbing viral transmission.
In each setting, given the amount of testing was the same, rapid testing reduced viral transmission better than the slower and more sensitive PCR testing. Since around two thirds of the cases are asymptomatic, many people continue to transmit the virus while they await their results. Contrary to PCR testing, rapid antigen tests enable self-testing and results in minutes which ensures immediate self-isolation.
Impact of Routine Testing
The study also points out to the impact of frequent testing in curbing the spread, shortening the pandemic, and saving lives. The researchers estimated that rapid testing three out of four people every three days could ultimately reduce the number of cases by 88% which could be enough to end the spread of the virus within six weeks. Indeed, recent studies show that routine antigen testing – typically two to three tests in a week – is as reliable as a PCR test. Indeed, data suggests that when testing was performed every three days, the sensitivity of both PCR tests and rapid antigen tests exceed 98%. However, when testing was performed once a week, while the sensitivity of PCR tests remained at 98%, the sensitivity of rapid antigen tests reduced to 80%. Data from Slovakia’s administration of population-wide serial rapid antigen testing in late 2020 also supports these findings. Together with some additional restrictions, observed prevalence decreased by 58% (95% confidence interval: 57 to 58%) within a week in the regions where two rounds of mass testing took place.
Several researchers also point out to the fact that rapid antigen tests are extremely effective in detecting SARS-CoV-2 when the viral load is high enough to infect other people. Even though, PCR tests are clearly superior in diagnosing a current infection, growing evidence suggests that rapid antigen tests may be more useful than PCR tests for determining infectiousness. In other words, while PCR testing might be too sensitive to specify infectious amounts of SARS-COV-2, rapid antigen tests only pick up on infections with high enough viral loads to infect other people. The concern that rapid antigen tests may miss cases in the early onset of infection is common, still, during that period, it is known that people are much less likely to transmit the disease. Many experts agree that the most practical way of curbing the spread of SARS-CoV-2 is the immediate detection and isolation of infectious people through frequent mass testing. In that case, a less sensitive test that results today might be a better option than a more sensitive option that results tomorrow.
Altogether, there is growing evidence that supports the prioritization of testing frequency and rapid turnaround. By assisting rapid risk assessment, ensuring immediate isolation, and facilitating mass screening, rapid antigen tests answer not only the growing demand for testing but allows us to test ourselves within our daily lives wherever and whenever the needed.
The New Normalcy and Us
As we adapt to a new normalcy, rapid antigen tests help as we return to a new normalcy, rapid antigen tests are crucial tools to prevent a return to a total lockdown. They present profound potential for performing mass screening and breaking the transmission chains while keeping the economy open. They can shorten the pandemic and simplify pandemic management. Indeed, even developed countries are struggling to answer to the demand for testing due to the cost of production and scarcity of resources. Unlike PCR, rapid antigen tests do not require laboratory technologies, expensive chemical supplies, or trained personnel. They can be easily stored and used in areas that lack advanced equipment such as remote regions and refugee camps. Therefore, these tests may help reduce the costs of testing, alleviate shortages, and improve healthcare equity. They can also reduce the overcrowding of hospitals and the exposure risk of healthcare professionals.
Overall, it is becoming clear that rapid antigen tests present extensive benefits for the pandemic response. By providing wider access and rapid results, rapid antigen tests allow everyone to test themselves wherever, whenever, and as often as needed. This ensures rapid risk assessment, immediate isolation, and access to healthcare. Recent studies and data support the prioritization of testing frequency and turnaround time and suggest that frequent mass testing by antigen tests could reduce the spread of SARS-CoV-2 to manageable levels in a matter of weeks. Finally, rapid antigen testing could contribute to equity of access and alleviate the pressure on resources, institutions, and the personnel.
In the light of this information, we offer you our RapidFor™ SARS-COV-2 Rapid Test Kits. Be a part of curbing the COVID-19 pandemic.
- James, A.S.; Alawneh, J.I. COVID-19 Infection Diagnosis: Potential Impact of Isothermal Amplification Technology to Reduce Community Transmission of SARS-CoV-2. Diagnostics2020, 10, 399. https://doi.org/10.3390/diagnostics10060399
- Crozier, A.; Rajan, S.; Buchan, I.; McKee, M. Put to The Test: Use of Rapid Testing Technologies for COVID-19. BMJ 2021, 372: n208. https://doi.org/10.1136/bmj.n208