THE highly contagious Covid-19 strain JN.1 has made its entrance into Malaysia during the festive season, said Universiti Malaysia Sarawak’s Institute of Health and Community Medicine director Dr David Perera.

Sixty-one samples collected in various parts of Sarawak on December 21 revealed the presence of two dominant Omicron sub-variants: JN.1 (49%) and HK.3 (26%).

“These samples were primarily identified in the Kuching/Samarahan areas, with a few cases in Sibu,” Perera said.

The World Health Organisation (WHO) on December 19 classified JN.1 as a Covid-19 variant of interest following its “rapidly increasing spread” around the globe.

According to virologist Prof Emeritus Dr Lam Sai Kit, the rapid spread of JN.1 in the last few months suggests its high transmissibility.

“It is probably better at evading our immune systems. JN.1 contains an additional mutation that affects the virus spike proteins which is essential for entry into host cells,” he told Bernama when contacted.

There has yet to be evidence that JN.1 poses an increased risk to public health relative to other circulating variants, he said.

However, it also does not mean that it presents less of a threat to those with poorer health.

“JN.1 infection presents primary symptoms similar to other Omicron variants. In elderly, immunocompromised individuals, and those with conditions like diabetes and heart diseases, sub-variants like JN.1 may lead to hospitalisation and, in severe cases, death.

“Even in young healthy individuals, it may result in long COVID,” said Dr Lam.

JN.1 was first detected in September 2023 in the US. By December 8, it made up about 15-29% of Covid-19 cases, according to the US Centers for Disease Control and Prevention.

Over 40 countries have already reported JN.1 including the UK, Denmark, Spain and Iceland.

Last week, China detected seven infections while India has just detected JN.1 by RT-PCR in its ongoing surveillance. Singapore, Thailand, Indonesia and Australia have also reported JN.1 in their respective countries.

The best defense remains getting vaccinated, masking up in crowded areas, and limiting exposure to people who have been infected, said Dr Lam.

“The good news is there are positive indications that existing vaccines, especially the bivalent and the updated monovalent ones, will generate antibodies that work against JN.1 and other currently circulating sub-variants.

“These antibodies may not block transmission or infections but should reduce the likelihood of severe disease and death,” he said.

However, he said, vaccinations are still necessary.

“Unvaccinated and uninfected people are ideal hosts for SARS-CoV-2 and ideal in generating new variants due to the absence of negative selection by antibodies, which makes it easier for the virus to replicate and produce new mutations,” he said.

Covid-19 would continue to mutate due to selection pressure, making it important for countries to continue monitoring antigenic changes and sharing the information with the rest of the world.

“JN.1 will not be the last sub-variant of the Omicron lineage,” said Dr Lam. – Bernama, December 22, 2023