Omicron strain Covid antigen rapid test: Is nasal swab enough?

Some scientists say people can transmit Omicron once it has infected their throat and saliva but before the virus has entered their nose, so swabbing your nose early in the infection will not detect virus.

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A small recent study from the United States supports that view. PCR testing of saliva from 29 people infected with Omicron detected the virus an average of three days before nasal samples tested positive for the antigen, also known as lateral flow testing.

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In general, rapid tests have lower sensitivity than laboratory-processed PCR tests, which means they produce more false negatives. But if you test positive, you almost certainly have COVID-19, making antigen tests a powerful tool to tackle the pandemic as demand for PCR tests driven by Omicron overwhelms labs. experience.

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As a result of recent studies, some experts in the United States now recommend that antigen test users swab their throat before swabbing their nose.

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All antigen tests with emergency use authorization from the US Food and Drug Administration use nasal samples, and it has expressed concerns about the safety of at-home throat swabs, and indicates that users should follow the manufacturer's instructions.

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In Israel, a top health official said people testing themselves for COVID-19 should swab their throat as well as their nose when using rapid antigen tests, even if it goes against the manufacturer's instructions.

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Several other countries, including the UK, have approved rapid antigen tests through both the throat and nose, or just the nose.

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In Germany, the Minister of Health said they will study the reliability of rapid antigen tests in detecting the Omicron variant and publish a list of the most accurate products.

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Written by: Linh Vũ

Source of translation: https://www.reuters.com/business/healthcare-pharmaceuticals/rapid-testing-omicron-is-nose-swab-enough-2022-01-10/