Modified Covid-19 test kit to catch probable Delta cases more quickly

Public health director says new PCR test will allow ‘more actions’ to prevent spread

A modified Covid-19 PCR testing kit – the standard test used by the HSE to detect the virus – is due to be used shortly to help identify probable Delta variant cases more quickly.

The Delta variant is not detected in the currently available Covid-19 screening assays or tests. The B.1.617.2 variant, first detected in India, is now the dominant strain in England and is spreading in the State.

Each variant of the virus has markers, and until now the dominant Alpha variant, first identified in Kent, has been detected in the screening of the PCR tests by checking for particular indicators.

Manufacturers of PCR testing kits are modifying them to provide more targeted information on variants of concern as more information on the new strains emerge.


"The new version of the PCR test will become available which will give us a strong heads-up about the Delta variant," said Dr Anthony Breslin, director of public health for HSE North West.

Currently it can take a number of weeks for genome sequencing on positive PCR tests to determine whether the latest Delta variant of concern is behind a case.

“The new PCR test that is coming looks at more hidden markers. It won’t tell us 100 per cent if it is the Delta. It will tell us if we have a Delta or a Kappa (variant) and we won’t be waiting for weeks to think we are dealing with Delta. We will be able to take more actions,” said Dr Breslin.

The Kappa B.1.617.1 variant is another strain that first emerged in India.

Cillian De Gascun, director of the State's National Virus Reference Laboratory, said he expects the new test to be available in the coming days, but he could not provide specific timing because it will have to go through a quick verification process.

Chief medical officer Dr Tony Holohan estimated last week that the more transmissible Delta variant accounted for 20 per cent of cases reported in the previous seven days.

“Basically, new assays are providing more targeted identification of probable variants of concern,” said Niamh O’Beirne, the HSE’s national lead for testing and tracing.

Most new Covid-19 cases are being assessed on the basis that they could be Delta variant cases given that this strain is as much as 60 per cent more contagious that the previous dominant strain.

Matter of time

Dr Breslin said that no laboratory-confirmed Delta variant cases had yet been identified in the northwest region he monitors but he felt it was only “a matter of time” before it was found there.

He said that an outbreak in north Sligo could potentially be the Delta variant because of the clinical picture seen in its transmission, with more than 40 people becoming infected.

“If it comes back as a Delta variant I won’t be surprised but we don’t have any evidence,” he said, adding that the virus was spreading through social events and beyond this into the community.

“Once the virus gets into the community it gets around the community. It gets into homes, into schools, into workplaces.”

Dr Breslin said he was concerned about the virus spreading more in general, regardless of the variant, because the virus would continue to mutate and change all the time. “Whatever variant it is, it does spread easily; some spread a bit more easily than others, but it spreads in any sort of opportunity it gets.”

He advised people to continue following the public health guidelines to curb transmission.

Simon Carswell

Simon Carswell

Simon Carswell is News Editor of The Irish Times