Cross-country comparison of Covid-19 testing policy

Last Updated 18 January 2021. Cellspect Co., Ltd.

The Covid-19 pandemic continues to pose a major threat to public health. Currently, Covid-19 tests fall into two types and three main categories, viral tests, including PCR and antigen test and antibody test. Viral tests are to detect whether a person is currently infected and antibody tests are to detect whether a person had an infection in the past. At present, the Covid-19 test policy in various countries differ due to the supply, test capabilities and medical capacity.

 

PCR test (RT-PCR)

PCR tests is the gold standard for diagnosing active coronavirus infection and still the most widely used and accepted method at the present. Official known cases mostly come from PCR tests. So far, most countries have open public testing (e.g., “drive through” testing) available to asymptomatic people, including US, Germany, France, Russia, South Africa, Japan, South Korea, China, Taiwan and Malaysia etc. Some countries provide testing for people showing Covid-19 symptoms, including UK, Canada, Australia, Finland, Spain, India, the Philippines and Thailand. In countries with limited medical and testing resources, testing is provided for those who both symptoms and meet specific criteria (e.g. key workers, admitted to hospital, came into contact with a known case), including Brazil, Mexico, Indonesia, and most Africa countries.

For international travelers, some countries accept only a negative PCR test performed less than 72 hrs before the flight for all travelers, such as France, Germany, Australia, China and Taiwan. 

 

Antigen test

Antigen test is not as sensitive (accurate) as PCR test and may have higher false negative rate, however, as rapid antigen tests have been developed and optimized, more and more countries have started accepting antigen test results. The WHO published on 11 September 2020 interim guidance on the use of rapid antigen tests for COVID-19 and recommends the use of rapid antigen tests that meet the minimum performance requirements of > 80% sensitivity and > 97% specificity. Now, when the availability of PCR testing is temporarily restricted (such as at airport), antigen testing is used. In the US, antigen tests now serve equally to PCR tests and is available in hospitals and public test stations. For other countries, antigen tests are used mostly in the airports for boarder control.

As a general rule, Japan tests all immigrants in the airports for Covid-19 and from the end of last July, the test method was changed from PCR test to saliva antigen test. From last October, Singapore have begun the use of antigen rapid tests to more quickly detect Covid-19 among migrant workers who undergo rostered routine testing. Travelers into most Europe countries (UK, Italy, Norway, Austria etc.), New Zealand and Africa are required to undergo antigen testing at the airports if they don't have a negative Covid-19 viral test without 72-hour. Beginning Jan. 26, the US CDC also require all people who plan to enter the US to show proof of a negative Covid-19 viral test (either a PCR test or an antigen test) prior to boarding. Apparently, due to the advantages of rapid tests, more and more countries and are using antigen tests on transportation and routine tests.

 

Antibody test (serology test)

Antibody tests determine whether a person has infection in the past but not suited for diagnosis of new infections. Therefore, antibody tests are mostly used for research or monitoring and not suited particular regulation policy so far. While there is a lot of uncertainty with this new virus, it is also possible that, over time, broad use of antibody tests and clinical follow-up will provide the medical community with more information on whether or not, and how long, a person who has recovered from the virus is at lower risk of infection if they are exposed to the virus again. Antibody tests can play a critical role in the fight against Covid-19 by helping healthcare professionals identify individuals who have antibodies to SARS-CoV-2 virus and have developed an adaptive immune response. In the future, this may potentially be used to help determine, together with other clinical data, whether these individuals may be less susceptible to infection. At this time, it is unknown for how long antibodies persist following infection and if the presence of antibodies confers protective immunity.

 References:

  1. U.S. Food and drug administration: https://www.fda.gov/

  2. World Health Organization: WHO https://www.who.int/

  3. Centers for Disease Control and Prevention: https://www.cdc.gov/

  4. Our world in Data:https://ourworldindata.org/

  5. OECD Policy Responses to Coronavirus (COVID-19):http://www.oecd.org/coronavirus/en/

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