CNA Explains: The FLiRT family of COVID-19 variants and what we know about the KP.2 strain – CNA

SHOULD WE BE WORRIED ABOUT KP.1 AND KP.2?

Globally there has not been a large number of hospitalisations. The mortality rate has also remained low.

Dr Leong said that there will be a minor uptick in cases in Singapore over the next few weeks due to the KP.1 and KP.2 variants.

He added, however, that this increase will be relatively minor compared to JN.1", as prior infection from JN.1 will confer significant protective benefit to KP.1 and KP.2.

The danger is that repeat infections could raise the risk of developing long-COVID, said Dr Fikadu Tafesse, a virologist at Oregon Health & Science University.

And there is no cure for long-COVID, Dr Leong noted. "It is a black hole of unknowns," he said, adding that people should get vaccinated to avoid the risk of long-term illness.

According to Dr Tambyah, MOH data suggests that COVID-19 numbers are already plateauing. "Things might change with the school holiday travel but I doubt it would change much," he said.

Against JN.1, the current vaccines designed around Omicron XBB.1.5 do generate some cross-reactive antibodies, said Professor Pekosz.

Studies have not been done with some of the newer variants, he noted, adding thatthose are likely to be "a little less cross-reactive".

Dr Leong provided a similar view.

We know that the XBB1.5 vaccine was about 50 per cent effective against the JN.1. We suspect that the current vaccine will be less effective in preventing infections with KP.1 and KP.2, he told CNA.

"The chief reason is the presence of the FLiRT mutations. The F amino acid became L and the R became a T. This allowed the virus to evade the existing immunity against COVID."

It has also been several months since many people received their last dose of the vaccine, and that immunity wanes over time.

Scientists say vaccination remains the best bet, especially against severe illness.

We firmly believe that it (the vaccine) is still effective against preventing severe disease such as hospitalisation and death, Dr Leong said.

Singapore's Health Ministry said that during the peak month of the previous JN.1 wave in December 2023, the incidence rate of COVID-19 hospitalisations and intensive care admissions among seniors aged 60 and above was 25 per cent higher in those who had not kept their vaccination updated compared to those who had.

The US CDC said the agency was continuing to monitor how vaccines perform against KP.2.

Governing bodies like the WHO and the US Food and Drug Administration are also expected to recommend a formulation for updated COVID-19 vaccines that will roll out in early fall.

New COVID-19 variants are likely to crop up after a decision is made, but Professor Pekosz said the goal remains to select a formulation that will match the circulating variants as closely as possible.

Dr Leong saidCOVID-19 test kits are able to detect the KP.1 and KP.2 variants.

"The COVID-19 test kit tests against the N protein. But the mutation of KP variants is mainly due to the spike protein," he explained.

"In fact, the N protein has been consistently stable with only minor mutations since the beginning."

Professor Pekosz said testing - whether at home or in a health care setting - will make sure people know what they are infected with, which can better guide a treatment plan.

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CNA Explains: The FLiRT family of COVID-19 variants and what we know about the KP.2 strain - CNA