WHO U.S. EU recommendation: How to use COVID-19 antigen test?

WHO U.S. EU recommendation: How to use COVID-19 antigen test? The WHO and the US and European CDC recommendation.  Rapid antigen testing can help improve overall COVID-19 detection capabilities.

As of February 2021, there have been more than 100 million people infected with COVID-19 globally. Among them, the number of confirmed cases in the United States has exceeded 27 million, and the number of confirmed cases in Russia and the United Kingdom has exceeded 3.8 million. In response to the development trend of the epidemic, WHO, disease control and other international organizations are constantly updating It is worth noting that many countries in the world (the United States, the European Union, Japan, etc.) have recognized the value of antigens in the early diagnosis of COVID-19 infection.

At present, the World Health Organization (WHO) has included 22 COVID-19 testing reagents in the emergency use list, including 2 antigen testing products. Let’s see how various organizations recommend the application of antigens…

World Health Organization

Rapid antigen testing can play an important role in guiding patient management, public health prevention and control decision-making, and COVID-19 surveillance, especially for grassroots areas that may hinder clinical diagnosis, treatment and prevention and control due to lack of nucleic acid testing capabilities or long testing time. value. A rapid antigen test should be performed 5-7 days after the onset of symptoms. According to WHO recommendations, based on the high specificity of the antigen test, a positive result indicates a new coronavirus infection. The WHO recommendations for the application of rapid antigen testing are as follows:

Responding to suspected COVID-19 outbreaks in remote areas, institutions and semi-closed communities where nucleic acid testing cannot be immediately obtained. The positive antigens of multiple suspected patients strongly indicate an outbreak, and infection control measures can be implemented as soon as possible accordingly;

Support epidemic investigations (for example, in closed or semi-closed groups, including schools, nursing homes, cruise ships, prisons, workplaces and dormitories, etc.). In the COVID-19 epidemic confirmed by nucleic acid testing, antigen testing can be used to screen high-risk individuals, and antigen-negative samples will be given priority to nucleic acid testing for confirmation;

Monitor the incidence trend in the community, especially during the epidemic or in areas where the community spreads widely (the positive predictive value and negative predictive value of the Ag-RDT result are sufficient to initiate effective infection control measures) incidence trends among basic staff and health workers ；

In areas with widespread community spread, rapid antigen testing can be used to detect and isolate positive cases early in health facilities, COVID-19 testing centers/sites, nursing homes, prisons, schools, frontline and health care workers, and to trace contacts. For antigen-negative patients, repeat antigen testing or preferably confirmatory nucleic acid testing should be performed as much as possible, especially in patients with symptoms;

Even if rapid antigen testing is not specifically authorized to test contacts of asymptomatic cases, this use can be considered.

European Center for Disease Control and Prevention

Rapid antigen detection helps to improve the overall COVID-19 detection capability, and has advantages in shortening the turnaround time and reducing costs, especially when the RT-PCR detection capability is limited. Rapid antigen detection can play a value in auxiliary screening of suspected patients, screening of asymptomatic high-risk groups, and regular monitoring. It is appropriate to use rapid antigen testing in high-prevalence situations, because a positive result may indicate a real infection, and rapid antigen testing in low-prevalence situations can quickly identify highly infectious cases.

Rapid antigen detection can be valuable for epidemic prevention and control in the following aspects:

Promote the clinical management of suspected patients admitted to the hospital;

Spread control: early detection of cases, tracing of contacts, and whole population testing;

Mitigating the impact of COVID-19 in the medical and social care environment: triage, early detection and isolation upon admission

Identify outbreaks in specific environments: early detection and isolation.

U.S. Centers for Disease Control and Prevention

The cost of antigen testing is low and most of the results can be reported in 15 minutes. In addition to the auxiliary diagnosis of suspected patients, for the rapid identification of infected persons and timely patient prevention and control measures, although the sensitivity of antigen testing may be lower than nucleic acid testing, antigen testing applications Still has important value.

Public Health Agency of Canada

New coronavirus antigen detection can be of value in the following (but not limited to) example scenarios:

Test selected symptomatic individuals within 5 days after the onset of symptoms (if positive, then perform confirmation testing);

Perform repeated tests on workers in remote work areas to prevent the introduction of the virus or minimize the chance of spreading in the workplace;

Proactively test workers in high-risk environments, including workers in large processing plants (such as meat processing plants), long-term care facility workers, and offshore/ocean workers;

In the case of an outbreak, if faster presumptions help inform public health actions, multiple symptomatic patients can be quickly detected on the spot;

Repeated tests were performed on prisoners who entered the correctional facility, who had gone out to visit the prison or had just arrived in the correctional facility.

Pan American Health Organization (PAHO)

In the first few days (approximately 1-5 days) after symptoms appear, viral proteins (antigens) are produced and can be tested by different methods (such as ELISA, immunofluorescence, and even rapid diagnostic testing). Generally speaking, antigen detection assays have acceptable specificity (depending on the assay method), so they can be used as confirmation criteria (combined with case definition, clinical and epidemiological history) and used to make public health decisions (such as isolation) .

South African Ministry of Health

In some cases, rapid antigen testing is of considerable value, especially considering the expected risk of re-epidemics. If implemented correctly, rapid antigen testing can improve health outcomes, improve contact tracing, and help control the spread of the virus.

“Japan’s New coronavirus Pathogen Detection Guidelines Third Edition”

For patients within 9 days of onset, antigen testing can be used as a confirmatory test. Especially for the extensive screening of medical institution staff, hospitalized patients, and in-and-out people in epidemic areas, antigen testing can be used as an important screening method when nucleic acid testing cannot be effectively implemented.

As of January 30, 2021, these international organizations and regions have compiled guidelines and recommendations for rapid detection of COVID-19 antigens, including WHO, ECDC, US CDC, Health Canada, South Africa Ministry of Health, Nepal Ministry of Health, Pakistan Health Ministry of Health, Ministry of Health of Malaysia, Ministry of Health of Japan, PAHO, etc., it can be seen that the application value of antigens in the world is affirmed.

WHO U.S. EU recommendation: How to use COVID-19 antigen test

(source:internet, reference only)

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