In the medical sphere, there is a probability that a body can carry a disease or an infection and exhibit no symptoms. Symptoms are basic features an individual exhibit which serves as an evidence for a particular disease or a disorder in the body. People who are carriers and yet exhibit no symptom of a disease or an infection are referred to as asymptomatic.
Post the declaration of COVID-19 as a global pandemic by the WHO on 11th March 2020, a Coronavirus disease 2019 (COVID-19) Situation Report 73 on 2nd April 2020 by the World Health Organization confirmed an asymptomatic COVID- 19 case. This affirms the fact that there are people who have COVID-19 and are living with the coronavirus unknowingly.
Therefore, the need to avoid crowded places and social distance among the safety precautions. Approximately 59% of all COVID transmissions came from asymptomatic transmissions.
This includes 35% from people who infect others before they show symptoms and 24% from people who never develop any symptoms. It can therefore be deduced that there is a considerable probability of existing asymptomatic cases and everyone is at risk. “The bottom line is controlling the covid-19 pandemic really is going to require controlling the silent pandemic of transmission from persons without symptoms.”- Jay C. Butler, CDC Deputy Director for Infectious Diseases.
Currently, 3 main COVID- 19 testing methods are available. These are the PCR test, Antigen test and the Serology test. The Polymerase Chain Reaction (PCR) testing and the Antigen testing detect if there is an active infection in the body. The Serology or the antibody test detects whether the individual has been infected in the past. The PCR test uses the genetic material of the virus in the nose, throat or around the respiratory tract to detect if there is an active infection.
The Antigen test looks for the proteins which is basically the structure of the virus to determine if an individual has an active infection. The Serology or the Antibody test finds the presence of antibodies in the blood to detect if the person has been infected in the past. The PCR test involves a swab that reaches the back of the throat through the nose. The antibody test, which is relatively comfortable, involves the taking of blood from a patient which can be done through the pricking of the finger.
Just like the PCR test, the antigen test also involves the nasal pharyngeal swab. The good news is unlike the PCR test, the antigen test can be done with a Rapid test and results would be available within 5 to 30 mins. This method of testing is faster than a blood sample being sent to a lab for testing. Antigen tests require little expertise. Antigen tests is the cheapest way to test for COVID.
“The U.S. Food and Drug Administration has issued the first emergency use authorization (EUA) for a COVID-19 antigen test, a new category of tests for use in the ongoing pandemic. These diagnostic tests quickly detect fragments of proteins found on or within the virus by testing samples collected from the nasal cavity using swabs.
This latest FDA authorization is for an antigen test, which is a new type of diagnostic test designed for rapid detection of the virus that causes COVID-19…One of the main advantages of an antigen test is the speed of the test, which can provide results in minutes.”- FDA Statement, Coronavirus (COVID-19) Update: FDA Authorizes First Antigen Test to Help in the Rapid Detection of the Virus that Causes COVID-19 in Patients.
Looking at the standing information on antigens provided by the science community, the use of antigen test kits is highly potent, roughly 78% effective in the detection of coronavirus.
A research by the North Dakota Health on 8th March 2021 which was adapted from the Texas Department of State Health Services reads that the PCR only helps determine whether a person has an active infection at the time of testing. It does not help determine who had an infection in the past. It also does not help determine which people who have been exposed to COVID-19 will develop active infection during the 2 weeks after exposure.
It adds that in some people, the virus can only be found by PCR for a few days at the beginning of the infection, so the test might not find the virus if the swab is taken more than a few days after the illness starts and in others, the virus can be found by PCR in the nose and throat for several weeks, longer than the time that they are contagious to other people.
The research furthers the fact that even with the serology or antibody test, results may be negative if it is used too close to the beginning of an infection and this disqualifies the serology test from being potent in detecting active COVID- 19 infections.
It states explicitly that some antibody tests may cross-react with other coronaviruses that are not SARS-CoV-2 thus leading to false test results and some antibody tests have low sensitivity and specificity and so, may not produce reliable results. We must bear in mind that research has not confirmed the protection level an already infected individual has which would prevent him or her from getting infected again.
Per the standing disadvantages of other testing methods and the research provided by the able science community, Kandifo Institute acknowledges the potency of antigen test kits. Currently, the advantages and disadvantages of antigen test kits outweigh that of the Polymerase Chain Reaction (PCR) testing and the Serology test.