In updated guidance on COVID-19 testing strategies, the World Health Organization (WHO) says it does not currently recommend widespread screening of people without symptoms, citing the cost of such a strategy and its ineffectiveness.
“Widespread testing of asymptomatic populations, including through self-testing, is not currently recommended, based on lack of evidence on impact and cost-effectiveness of such approaches and the concern that this approach risks diverting resources from higher priority testing indications,” the guidance stated.
However, “countries with the resources and desire to expand testing to the general public (regardless of symptoms) should demonstrate that they have the necessary public health infrastructure in place to respond to positive results and that resources are not being taken away from the testing of suspected cases, which is the top priority,” the WHO told The Epoch Times via email.
Testing should be directed “to where they are expected to have the biggest public health impact,” the WHO said, adding, “this means that all those who are suspected [as defined by the WHO] to have COVID-19 based on symptoms should be prioritized for testing,” irrespective of their vaccination status or disease history.
But in areas with ongoing community transmission, anyone who has come in contact with a probable or confirmed case should still quarantine for 14 days regardless if they are asymptomatic and have not been confirmed positive.
The Centers for Disease Control and Prevention (CDC) says in its most updated guidance that people who are asymptomatic and not vaccinated should be quarantined and tested if they were in close contact with a COVID-19 positive individual.
“Viral testing is recommended for unvaccinated individuals who are close contacts of persons with COVID-19,” the CDC said. “These individuals should be tested immediately after being identified, and if negative, tested again in 5-7 days after last exposure or immediately if symptoms develop during quarantine.”
Whereas, fully vaccinated individuals do not need to be quarantined, tested, “or be restricted from work” after being in close contact to individuals with suspected or confirmed COVID-19 if they do not have COVID-like symptoms, “as their risk of infection is low,” according to the CDC. However, they are recommended to self-monitor for symptoms of COVID-19 for 14 days after exposure.
The CDC says testing is still recommended for “fully vaccinated residents and employees of correctional and detention facilities and homeless shelters.”
People are considered fully vaccinated two weeks after their second dose of a messenger RNA vaccine or a single-dose Johnson & Johnson vaccine.
The WHO’s current guidance on prioritizing tests for people with symptoms is consistent with what the guidance had been prior to the pandemic in treating and diagnosing respiratory viral outbreaks—including the 2003 Severe Acute Respiratory Syndrome (SARS) outbreak and the 2012 Middle East Respiratory Syndrome (MERS) outbreak—which was to predominantly focus on symptomatic cases to stop the transmission of the disease.
Data has indicated that asymptomatic spread is not as prevalent as earlier studies claimed it to be and that the risk of transmission from asymptomatic patients is low.
COVID Cases May Be Confirmed with Antigen Test
Throughout the pandemic last year, the standard for diagnosing a CCP (Chinese Communist Party) virus infection was through a PCR (polymerase chain reaction) test with cycle threshold values of 40 cycles or higher. This raised concerns that there may be an overreliance on and a misuse of the test as a diagnostic tool since it can’t differentiate between a live infectious virus and an inactivated virus fragment that isn’t infectious.
Individuals who had a positive PCR test with or without symptoms of COVID-19 were considered a case and added to the daily COVID-19 case count.
The CCP virus causes the disease COVID-19.
The WHO then updated its guidance on the use of PCR tests on Jan. 20, 2021, cautioning lab experts and in vitro diagnostic medical devise users to not rely solely on the results of the PCR test to diagnose COVID-19. Rather, a patient’s health history and epidemiological risk factors should also be considered alongside the PCR test in diagnosis.
Now, verification of a COVID-19 case can be done through an antigen test, instead of through a nucleic acid amplification test (NAAT) such as the widely used PCR test.
In the updated recommendation, the WHO states that while “NAAT is considered as a reference standard for diagnosis of SARS-CoV-2 infection,” an antigen test can be used to diagnose a CCP infection “where NAAT is not available or where results will be delayed by more than 48 hours.”
Three scenarios where a nucleic acid amplification test is not required in addition to an antigen test result include:
- In symptomatic people in high prevalence settings, it is not necessary to confirm positive antigen test results by NAAT, while a negative antigen test result “may be confirmed by NAAT at clinical discretion.”
- In low prevalence settings, confirmation of negative antigen test results by NAAT is not necessary, whereas a positive antigen test result is up to the clinic to confirm it with NAAT.
- In asymptomatic people “that are contacts of confirmed cases or are frequently exposed, such as health care and long-term care facility workers,” an antigen test result is not necessary to be confirmed by NAAT.
Antigen tests are immunoassays that can detect if an individual has an active CCP virus infection in about 15 to 30 minutes and is less sensitive than a PCR test. According to the WHO, antigen tests are “sensitive only for detection of patients with a high viral load e.g. cycle threshold (Ct) values [of approximately] 25-30.”