Simplified Covid-19 PCR test is less sensitive, says Hong Kong health expert, questions rationale for change

Simplified Covid-19 PCR test is less sensitive, says Hong Kong health expert, questions rationale for change

A respiratory disease expert has questioned the government’s plan to simplify covid-19 testing by removing the nasal swab element from testing to leave only the throat swab in some facilities, saying the throat swab alone is not as sensitive.

Covid-19 community testing center. File Photo: GovHK.

Starting Tuesday, free tests offered at community testing centers and the airport will adopt the simplest method to speed up sample collection and increase testing capacity, the government said. He said the accuracy of the tests will not be affected.

In the meantime, self-paid trial services will not be affected, unless otherwise requested.

lower sensitivity

Respiratory medicine specialist Leung Chi-chiu, speaking on an RTHK show on Monday, said he “couldn’t understand” the policy change, especially when it applied to people who had to undergo mandatory testing. The doctor cited studies abroad that say the sensitivity of a combination swab reached about 97 percent, while a throat swab was only about 68 percent.

“About a third of that sensitivity was lost,” Leung said. “With the government putting a lot of resources into this…if testing is mandatory, but a less sensitive method is adopted, it goes against the original intent of [safeguarding] public health.”

A mobile Covid-19 testing center at Maple Street Playground in Sham Shui Po during the city’s fifth wave. Photo: Hong Kong Government.

In announcing the policy change, the government said health authorities in mainland China have recommended throat swabbing for large-scale testing. But Leung said the situation in Hong Kong was different.

“The mainland does not have good herd immunity and tries to avoid cross-infection during testing, so procedures need to be streamlined,” he said.

As Hong Kong had started to return to normality and was protected with herd immunity, Leung said testing for Covid-19 could generally be scaled back and done only in a specific area if there was a risk of transmission.

Former health director admits to underestimating the fifth wave

In an interview with Ming Pao on Monday, former health chief Sophia Chan admitted authorities had underestimated the infection figures, but denied being unprepared.

At the height of the outbreak, which saw daily Covid cases spike to more than 76,000 in early March, public hospitals were overwhelmed and patients, including children and the elderly, were left to wait outside emergency rooms in the cold.

Hong Kong has registered more than 10,000 dead since the fifth wave It started on December 31 last year.

Sophia Chan. File photo: Kelly Ho/HKFP.

Chan told Ming Pao that “preparedness and response” was needed to handle an infectious disease outbreak, and at the time health authorities believed they were well prepared and ready to respond if the situation worsened.

“Just because problems arose in our response, that doesn’t mean [we] poorly prepared,” Chan told the newspaper.

But he admitted the government could have done better by making hospital beds available and more flexible in its arrangements.

When asked if the previous government should apologize to Hongkongers and the families of those who died, Chan was quoted as saying: “[t]here it makes no sense to look at this issue. [We should] expect.”

Hong Kong reported 4,988 cases on Sunday, bringing the total number of cases to 1.95 million and related deaths to 10,470.

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